The structure of scientific inferenceProbability, gradual consensus, incremental evidenceBayesian epistemologyInference to the best explanation, and bayesianismIntuicionismo HumeInductivismo (desde Bacon a Newton…)Hypotheses non fingo, I frame no hiphotesis, I feign no hiphotesis…Hipótesis: "Suposición de una cosa para inferir una consecuencia".Tesis: "Conclusión que se mantiene con razonamientos" (en maths: teorema? Vs axiomas y postulados no razonados..)Creación de enunciadosCálculo de enunciados y proposicionesA logical calculus of the ideas inmanent in nervous activity El problema de la creacion de hipótesisEl problema de la inducciónEmergenciaSupervenience (emerge de, se deriva de, se apoya y esta incluida en…)Teoria de sistemas, sistemas complejos, ciberneticaIntelecto agente, posibleIntellectus agensActive intellectEspontaneidad intelectualLa imaginación de thought-experiments y “mágica cognitiva”Los experimentos mentales, el modelado y simulación de fenómenos y procesos, los esquemas conceptuales, la caracterización, la extracción de parámetros, el análisis de sensibilidad, la observación de simulaciones y comportamientos, la optimización.El contexto de “descubrimiento (de una hipótesis, de una teoría, de una ley)” vs el contexto de “justificación” (de hipótesis o presuntas leyes puestas quasi arbitrariamente y con el fin de buscar su justificación)Induccionismo fisicoCausalidadCinematicaOrbitalesConjetura-refutacionCiencia normal de KuhnAnomalíasParadigma-“exemplar” de KuhnModelos y analogíasPopper-Feyerabend-Kuhn-LakatosAgainst Method de Feyerabend, esto es lo que hay, no todo es avance, imposición de ciencia=imposición de fe…etcLa estructura de las revoluciones cientificas de Kuhn, ciencia normal en un paradigma establecido vs revolución del edificio teórico, posiblemente inspirada desde hindsight y promise and aesthetical appeal Lakatos methodologies of research programmes MRP, methodologies of scientific reserach programmes SRP, tendencies degenerativas o confirmativas de un RP, cambio de modelo teorico poco a poco, assessment gradual mediante hipótesis auxiliares…Las Teorías no son bruscamente refutables o falsables en el sentido de Popper. Lakatos o qué se puede retener de Feyerabend, Kuhn y Popper

Lakatos progressive problem-shifts involves novel predictions developed in accordance with positive and negative heuristicsPerspectiva meta-metodologica (sobre analisis historico de metodologías dadas como hechos) de LakatosConjeturas y refutaciones de PopperConsensoMetodo especulativo en el progreso del consensoEvidencia en Descartes y Balmes y CanalsBerkeley y las ideasHipótesis=modelo perfecto en Platón, Galileo como platónicoOckham//ScotoPlausibleVerosimilExplicación cientificaExplicación causal vs explicación funcionalToda explicación debe ser causalEstimaciónPrior probabilitiesPlausibility constraintsPoperianos contra inductivistasDialogo y hermeneutica en el consenso cientificoDemarcacion poperiana de lo que es conocimiento cientifico (falsable) de lo que no lo esEmpiricismo constructivista (Van Fraassen) vs realismo: teorias empíricamente adecuadas para salvar las apariencias de los fenómenos y datos de observacion, no tanto para saber que son “verdad” o encontrar la verdadUnderdetermination of theories by dataIBE inference to the best explanation vs deductive-nomic model D-N vs hipotetico-deductivoPrediccion de resultados desde una teoria vs acomodacion y encaje de datos en el proceso de construccion de una teoríaDescubrimiento de fenomenos y sus causas vs inferencia de comportamiento de dispositivos y sistemas artificiales y su relativamente rápida caducidad en su interés Observación y calculo, pero toda observación esta “cargada” de teoría…Theorical pre-conceptions en toda inferencia de hipótesis: contra el inductivismo puro de Bacon, donde bastan los datos para obtener induccionesLos datos son selectivos, seleccionados siempreEl problema de elegir los experimentos, diseño de experimentos, siempre desde hipótesis o teorias a explorar, cargados o presididos por teorias…Ontología, Lógica y Epistemología subyacentesProposicionEs un enunciado o juicio el cual solo puede originar uno y solo uno de los términos verdadero o falso.Las proposiciones más comunes que se utilizan son: axiomas, postulados, teoremas y corolarios.AxiomasEs una verdad que no requiere demostración y se la cumple en todas las ciencias del conocimiento.Postulados

Es una proposición aceptada como verdadera. A diferencia de los axiomas, estos se los emplea generalmente en geometría, los mismos que no se han constituido al azar, sino que han sido escogidos cuidadosamente para desarrollar la geometríaTeoremaEs la proposición cuya verdad necesita ser demostrada: una vez que el teorema se ha probado se lo puede utilizar para la demostración de otros teoremas, junto con axiomas y postulados.Un teorema consta de: hipótesis y tesis: Hipótesis: son las condiciones o datos del problemaTesis: es la propiedad a demostrarse.CorolarioEs la consecuencia de un teorema demostrado.Los problemas son hoy complejos, más difícil inducción y más difícil deducción, al menos cadenas más largas de argumentación y más lejanas de la observación inmediata, más indirectos, menos claros y concretos (o igual de concretos)Imposibilidad de certeza, pero imposibilidad igualmente de refutar por los complejos condicionantes en los que se observa y aserta una refutación (inseguridad de tener el control), no clara la “drastica falsabilidad” de Popper

Teoría (cualitativa) de confirmaciones // Razonamiento Bayesiano

http://vms.cc.wmich.edu/~mcgrew/confirm.htm

http://www.filosoficas.unam.mx/~posgrado/prog_maest.html

http://www.filosoficas.unam.mx/~posgrado/prog_maest.html

F. PROGRAMA DE CURSOS PROPEDEUTICOS Y DE LOS CURSOS OBLIGATORIOS DE LA MAESTRIA

1. Cursos propedéuticos

1.1 Curso propedéutico de filosofía de la ciencia

Objetivo General:

Identificar los principales temas y problemas de la filosofía de la ciencia contemporánea, comprender las principales posiciones y respuestas al respecto y evaluar críticamente su desarrollo en el presente siglo.

1. Introducción.

El concepto tradicional de ciencia; sus supuestos ontológicos, lógicos y epistemológicos fundamentales. Breve crítica a cada uno de ellos desde el estado actual de las ciencias y de la epistemología.

2. La concepción stándard de las ciencias:

a) El positivismo lógico y sus propuestas sobre la estructura, método, criterio de demarcación y objetivos del conocimiento científico. Problemas con cada una de ellas.

•b) La supuesta reacción popperiana al positivismo: las coincidencias y divergencias con el mismo. El rechazo de la dicotomía teórico-observacional, el método deductivo de contrastación, la falsabilidad como criterio de demarcación, el carácter progresivo de las explicaciones científicas satisfactorias y el sobredimensionamiento del progreso científico como aumento del grado de verosimilitud de las hipótesis. Crítica a cada una de dichas propuestas.

3. La concepción no-estandard de las ciencias:

•a) Las notas distintivas de tal nueva concepción: la historización de la filosofía de las ciencia, el rol constitutivo de las teorías y/o paradigmas, el abandono de la distinción de contextos y de la búsqueda de criterios de demarcación, el énfasis en la actividad productora de la ciencia sobre el producto, la re-introducción del sujeto cognoscente, la incidencia de valores extra-científicos, y la nueva elucidación de la objetividad y racionalidad científica.

•b) La ejemplificación de tales cambios en la concepción de Thomas Kuhn. Paradigmas, ciencia normal y revoluciones científicas. Problemas y cambios en la posición de Kuhn al respecto.

•c) Los programas de investigación (I. Lakatos): núcleo tenaz y heurística positiva. La reconstrucción raciofnal de la historia de las ciencias. Problemas con los remanentes popperianos en dicha propuesta.

•d) Paul Feyerabend y su anarquismo epistemológico. Las relaciones fundamentales entre sus propuestas centrales: todo vale, pluralismo teórico, contrainducción, teoría pragmática de la explicación y postura heterodoxa acerca del progreso y la racionalidad científica.

•e) Tesis y cambios en el enfoque de solución de problemas de Larry Laudan: (i) la aplicación inicial del mismo al proyecto científico (1977), (ii) el modelo de reticulado en su nueva teoría de la racionalidad científica (1984) y (iii) la epistemología normativa-naturalista (1987).

f) Breve evaluación de las dificultades más importantes en cada uno de ellos.

4. Bas van Fraassen, la reacción y después

•a) El empirismo constructivo y su crítica al realismo científico. Respuesta a tales críticas y la explosión de realismos disminuídos.

b) Tendencias actuales en filosofía de las ciencias: problemas dominantes y enfoques relevantes para su tratamiento.

Evaluación: A través de exámenes escritos (parciales y final).

BIBLIOGRAFIA

Carnap, R. (1959). "The Elimination of Metaphysics Through the Logical Analysis of Language", en A. Ayer, ed., Logical Positivism. New York: The Free Press, pp. 60-82.

Chalmers, A. (1982). "The Logic of Discovery: An Analysis of Three Approaches", Ibid., pp. 417-430.

Feyerabend, P. (1972). Against Method. London: Verso. Caps. 1-5 y 18.

-----(1975). "Consuelos pare el especialista", en I. Lakatos y A. Musgrave, eds., La Crítica y el Desarrollo del Conocimiento. Barcelona-Buenos Aires-México: Grijalbo, pp. 345-390.

-----(1989). `How to Be a Good Empiricist", en B. Brody y R. Grandy Readings in the Philosophy of Science, op. cit., pp. 104-122.

Giere, R. (1988). Explaining Science. Chicago: University of hicago Press.

Giere, R. (1989). "Philosophy of Science Naturalized", en B. Brody y R. Grandy, eds., Readings in the Philosophy of Science, op. cit., pp. 379-397.

Goodman, N. (1989). "The New Riddle of Induction", en B. Brody y R. Grandy, eds., Readings in the Philosophy of Science, op. cit., pp. 309-312.

Hacking, I. (1981). "Lakatos´s Philosophy of Science", en I. Hacking, ed., Scientific Revolutions, op. cit., pp. 128-143.

-----(1984). Representing and Intervening. Cambridge: Cambridge University Press.

Hanson, N. (1967). "Observation and Interpretation", en S. Morgenbesser, ed., Philosophy of Science Today. New York- London: Basic Books, pp. 89-110.

Hempel, C. (1959). "The Empiricist Criterion of Meaning", en A. Ayer, ed., Logical Positivism, op. cit., pp. 108-132.

-----(1965). "Science and Human Values", en Aspects of Scientific Explanation. New York: The Free Press, pp. 81-98.

-----(1965). "The Theoretician´s Dilemma: A Study in the Logical of Theory Construction", Ibid., pp. 173-228.

Hempel, C. (1966). Philosophy of Natural Science. Englewood Cliffs, New Jersey: Prentice Hall. Caps. 3, 4 y 6.

-----(1967). "Scientific Explanation", en S. Morgenbesser, ed., Philosophy of Science Today, op. cit., pp. 78-89.

Kuhn, Th. (1972). La Estructura de las Revoluciones Científicas. México: Fondo de Cultura Económica.

-----(1975). "Lógica del Descubrimiento o Psicología de la Investigación?", en I. Lakatos y A. Musgrave, eds., La Crítica y el Desarrollo del Conocimiento, op. cit., pp. 81-114.

-----(1990). "The Road Since Structure", en A. Fine, M. Forbes y L. Wessels, eds., PSA 1990, vol. 2. East Lansing, Michigan: Philosophy of Science Association, pp. 3-13.

Lakatos, I. (1975). "La falsación y la metodología de los programas de investigación", en I. Lakatos y A. Musgrave, eds., La Crítica y el Desarrollo del Conocimiento, op. cit., pp. 203-342.

-----(1975). "Historia de la ciencia y sus reconstrucciones racionales", Ibid., pp. 455-510.

Laudan, L. (1977). Progress and Its Problems. Los Angeles-Berkeley: University of California Press.

-----(1990). Science and Relativism. Chicago-London: University of Chicago Press.

Nagel, E. (1979). The Structure of Science. New York: Harcourt, Bruce and World, Inc. Caps. 3-4.

Popper, K. (1962). La lógica de la investigación científica, Madrid: Tecnos.

-----(1965). "Conjectures and Refutations", en Conjectures and Refutations. The Growth of Scientific Knowledge. New York: Harper Torchbooks, pp. 33-65.

Putnam, H. (1981). "The Corroboration of Theories", en I. Hacking, ed., Scientific Progress, op. cit., pp. 80-105.

Quine, W. (1974). "Two Dogmas of Empiricism", en From a Logical Point of View. Cambridge, Mass.: Harvard University Press, pp. 20-46.

van Fraassen, B. (1980). The Scientific Image. Oxford: Oxford University Press.

1.2 Curso propedeutico de teoría del conocimiento

En este curso se examinarán las corrientes filosóficas más sobresalientes que han surgido en el área de la teoría del conocimiento en el siglo presente, teniendo como objetivos: (1) entender correctamente las teorías bajo escrutinio, sus diferencias y semejanzas y (2) evaluarlas críticamente; y (3) establecer una comparación de sus ventajas y dificultades teóricas. Los temas que consideraremos: El fundamentalismo

epistemológico, teorías de la coherencia, teorías externalistas y causales, epistemología naturalizada, escepticismo y el problema de la inducción.

Temas:

1.- Fundamentalismo (clásico y contemporáneo) 2.- Coherentismo. Justificación internalista; holismo; falibilismo. 3.- Teorías Externas y Naturalismo. 4.- Escepticismo. Escepticismo clásico y contemporáneo; Escepticismo metódico y como sistema.

BIBLIOGRAFÍA

Jonathan Dancy, Introducción a la epistemología contemporánea. (Madrid: Tecnos, 1993), págs. 71-80.

Nelson Goodman, "Sense and Certainty", en Empirical Knowledge, ed. por Chisholm y Swartz, (Prentice Hall, 1973).

Laurence Bonjour, "Can Empirical Knowledge have a Foundation?" en American Philosophical Quarterly 15 (1978), 1-13.

L. Bonjour, "The Coherence Theory of Empirical Knowledge" en Philosophical Studies, 30 (1976) pp. 281-312.

Richard Fumerton, "A Critique of Coherentism" en The Theory of Knowledge, antología por Louis Pojman (Wadsworth, Inc. 1993).

Alvin I. Golman, "The internalist Conception of Justification", en Midwest Studies in Philosophy, ed. por Peter A. French (Minneapolis: University of Minnesota Press, 1980).

Alvin I. Golman, "A Causal Theory of Knowing" en The Journal of Philosophy 64, 12 (1967), pp. 355-372.

Laurence Bonjour, "Externalist Theories of Empirical Knowledge", en Midwest Studies in Philosophy.

W. V. Quine, "Epistemology Naturalized" en su libro Ontological Relativity and Other Essays (New York: Columbia U. P., 1969) pp. 68-90.

Thomson Clarke, "The Legacy of Skepticism" (copia)

Barry Stroud, "The Significance of Scepticism" en Transcendental Arguments and Science antología por P. Bieri, Horstman, y L. Kruger, D. Reidel Pub. Co. (Dordrecht, Holland: 1979).

1.3 Curso propedeutico de lógica

Objetivos Generales: Al final del semestre los alumnos tendrán los rudimentos de lógica necesarios para empezar a construir sus propios análisis de proposiciones científicas que no involucren nociones modales o cuantificación de orden superior.

Introducción al razonamiento crítico

Se estudiará cuándo es adecuado o incluso necesario ofrecer razones con énfasis en Filosofía de la Ciencia. Los temas serán tomados de los libros de Barker, Barry, Bedau, Browne & Keeley, Engel, Fogelin, Johnson & Blair, Missimer, Moore & Parker, Ruggiero, Runkle, Russow & Curd, Seech y Thomas.

Conceptos Básicos:

• Lógica y razonamiento • Oraciones, proposiciones y aseveraciones • Lenguajes naturales y lenguajes formales • Forma lógica • Validez y verdad • Definiciones • Lenguaje emotivo, metáforas, ambigüedad, vaguedad y eufemismos

Argumentos:

• Relaciones causales, temporales y retóricas entre las partes de un argumento • Tipos de argumentos: • Deductivos, inductivos, abductivos, por analogía, probabilísticos y estadísticos.

Estructura de argumentos:

• Partículas indicadoras de premisas y conclusiones • Diagramas

Evaluación de argumentos:

• Falacias formales y falacias materiales • Contraejemplos

Introducción a la lógica formal de primer orden

Silogismos y diagramas de Venn: usos y limitaciones

Estilos lógicos: deducción natural, método axiomático y lógica algebráica

Lógica proposicional:

• Funciones veritativo-funcionales y tablas de verdad • Tautologías, contradicciones proposicionales, contingencias proposicionales • Formas normales y conjuntos adecuados de conectivas • Diferencias entre la simbolización lógica y los lenguajes naturales: • Errores de traducción: doble negaciones, disyunciones exclusivas, etc. • Diferencias entre el condicional material y la implicación lógica. • Qué se puede probar mediante simbolización y qué no se puede probar. • Reductivo y prueba condicional.

Lógica de predicados de primer orden:

• Cuantificadores • Substitución y oraciones libres • Validez

Evaluación: Examenes escritos.

BIBLIOGRAFÍA

Se utilizarán libros de Introducción a la Lógica como:

• Copi I. Introducción a la Lógica, Eudeba.

• Enderton, H. B. Una Introducción Matemática a la Lógica, IIF/UNAM, 1987 México.

• Ferrater, Mora Introducción a la Lógica Matemática, FCE, 1973.

2. Cursos obligatorios de la maestría

2.1 Filosofía de la ciencia I

•Se revisarán algunos de los problemas más importantes que ha abordado la filosofía de la ciencia del siglo XX, en relación con aspectos sincrónicos -lógicos, epistemológicos y metodológico s- de la ciencia, procurando en todos los aspectos analizar diferentes corrientes y perspectivas en la forma de plantear y pretender resolver los problemas. El

profesor se asegurará que por medio del análisis de los problemas y de las corrientes, el estudiante tenga claridad acerca de la naturaleza y de los objetivos de la filosofía de la ciencia.

•El profesor tendrá la responsabilidad de que el alumno estudie algunos de los textos fundamentales en la filosofía de la ciencia de este siglo, algunos de los cuales se mencionan en la bibliografía anexa.

Algunos de los problemas que se deberán abordar serán los siguientes:

1. RACIONALIDAD DE LA CIENCIA • La racionalidad científica como problema fundamental de la Filosofía de la Ciencia. Enfoques normativistas y descriptivistas (naturalistas).

2. PROBLEMAS DE EXPLICACION • Naturaleza de la explicación científica. • Tipos de explicación científica. • Explicación y predicción.

3. EL CONCEPTO DE LEY CIENTIFICA • Caracterización de las leyes científicas. • Tipos de Leyes. • Criterios de legalidad.

4. EL CONCEPTO DE TEORIA CIENTIFICA • Tipología, lógica y semántica de conceptos. • Naturaleza y estructura de las teorías científicas: diversas concepciones. • Interpretaciones y modelos. • Relaciones interteóricas. El problema de la reducción de teorías.

5. PROBLEMAS DE CONTRASTACION Y CONFIRMACION • Sintaxis de la confirmación. • Paradojas de la confirmación. • El problema de la inducción y de la contrastación del conocimiento científico. • La metodología falsacionista. • Diversas concepciones sobre la base empírica y su dependencia de otras teorías. • La epistemología anarquista: contra el método y contra la ciencia. • Confirmación y probabilidad.

6. TEORIAS Y MODELOS • Tipología de Modelos. • El papel de los modelos en la investigación científica. • Modelos y metáforas en la investigación científica.

7. TEORIA Y OBSERVACION • La dicotomía teoría-observación. • Caracterización de los términos empíricos. • Términos teóricos y términos observacionales.

• Eliminabilidad de los conceptos teóricos. • Intentos reduccionistas. • Entidades teóricas y entidades no-observables. • Carga teórica de la observación. • La evolución del concepto de observación.

Evaluación: Exámenes parciales y un examen final escrito.

BIBLIOGRAFIA que se sugiere:

Achinstein, Concepts of Science, John Hopkins University Press, Baltimore, 1968.

Bachelard, G., La Formación del Espíritu Científico, Siglo XXI, Buenos Aires, 1972.

Boyd, R., Gasper P., y Trout, J. D., The Philosophy of Science, Cambridge Mass., The MIT Press, 1991.

Brown, H. I., Perception, Theory and Commitment. The New Philosophy of Science, The University of Chicago Press, Chicago and London, 1977.

Bunge, M., La Investigación Científica, Ariel, Barcelona, 1969.

Carnap, R., Fundamentación Lógica de la Física, Sudamericana, Buenos Aires.

Chalmers, A. F., ¿Qué es esa cosa llamada ciencia?, Siglo XXI Editores, Madrid, 1983.

Duhem, P., "Physical Theory and Experiment", en Feigl y Brodbeck 1953, 1906.

Feigl, H. y Brodbeck, M. (eds.), Readings in the Philosophy of Science, Appleton-Century-Crofts, Nueva York, 1953.

van Fraassen, Laws and Symmetry, Oxford University Press, Oxford, 1989.

Goodman, N., Fact, Fiction, and Forecast, Bobbs-Merril, New Yord, 1965. (la. ed. de Harvard University Press, 1955).

Hacking, I. (ed.), Scientific Revolutions, Oxford University Press, Oxford, 1981.

Hacking, I., Representing and Intervening, Cambridge Press, Cambridge, 1983.

Hanson, N. R., Patterns of Discovery, Cambridge University Press, Cambridge, 1958.

Harré, R., The Principles of Scientific Thinking, University of Chicago Press, Chicago, 1970.

Hempel, C. G., Aspects of Scientific Explanation and Other Enssays in the Philosophy of Science, The Free Press, New York, 1965. Traducción al español: La Explicación Científica, Paidós, Buenos Aires, 1965.

Hempel, C. G., "On the Standard Conception of Scientific Theories", en Minnesota Studies in the Philosophy of Science, Vol. 4, M. Radner y S. Winokur (eds.), University of Minnesota Press, Minneapolis, 1970.

Hempel, C. G., Filosofía de la Ciencia Natural, Alianza Universidad, Madrid, 1983.

Hesse, M., The Structure of Scientific Inference, University of California Press, 1974.

Kitcher, P. y Salmon, W., Scientific Explanation, vol. XIII, Minnesota Studies in the Philosophy of Science, Minneapolis, University of Minnesota Press, 1989.

Martínez, S., "Qué es una ley irreductiblemente estadística?": El caso de la mecánica cuántica", Diánoia 37, 1991.

Moulines, C. U., Exploraciones Metacientíficas. Estructura, desarrollo y contenido de la ciencia, Alianza Universidad, Madrid, 1982.

Nagel, E., La Estructura de la Ciencia, Buenos Aires, Paidós, 1978.

Nidditch (comp.), The Philosophy of Science, Oxford University Press, Oxford, 1968.

Olivé, L. y Pérez Ransanz,A.R. (eds.), Filosofía de la ciencia: teoría y observación, Siglo XXI Editores/UNAM, México, 1989.

Otero, M., La filosofía de la ciencia hoy: dos aproximaciones, UNAM, México, 1977.

Pérez Ransanz, A.R., "Azar y explicación: algunas observaciones", en Crítica No. 66, diciembre de 1990 pp. 39-54, 1990.

Popper, K. R., The Logic of Scientific Discovery, Hutchinson, Londres, 1a. ed. en inglés 1959, 1935.

Popper, K. R., Conjetures and Refutations, Harper & Row, Nueva York, 1963.

Popper, K. R., Objetive Knowledge: an evolutionary approach, Oxford: Clarendon Press, 1972.

Putnam, H., "What Theories are not", en Logic, Methodology and Philosophy of Science, E. Nagel, P. Suppes y A. Tarski (eds.), Stanford University Press, 1962. (Trad. en Olivé y Pérez Ransanz 1989, pp. 312-329), 1960.

Railton, P., "Probability, Explanation and Information", Synthese, vol. 48, pp. 233-56, 1981.

Reichenbach, H., Experience and Prediction, University of Chicago Press, Chicago, Ill, 1938.

Rescher, N., Scientific Explantion, The Free Press, Nueva York, 1970.

Rolleri, J. L. (ed.), Estructura y Desarrollo de las teorías Científicas, IIF/UNAM, México, 1986.

Salmon, W., Four Decades of Scientific Explanation, in Kitcher and Salmon, pp. 3-219, 1989.

Salmon, W., "Scientific Explanation: Causation and Unification", en Crítica No. 66, pp. 3-23, Diciembre de 1990.

Shapere, D., Reason and the Search for Knowledge, Reidel Publishing Co., Dordrecht, Holland, 1984.

Stegmüller, W., Estructura y Dinámica de Teorías, Segundo tomo de Teoría y Experiencia, 1983. (Edición del original alemán: Springer Verlag, Heidelberg, 1973).

Suppe, F. (ed.), The Structure of Scientific Theories, University of Illinois Press, Urbana-Chicago-London, 2nd. ed., 1977.

von Wright, G. H., Explicación y Comprensión, Alianza Editorial, Madrid, 1979.

2.2 Lógica I

• Se estudiarán elementos de la teoría de conjuntos, y las nociones de lenguaje y de sistema formal. Se trabajará con cálculos de deducción natural y axiomáticos, y se estudiarán en detalle el cálculo de enunciados. Se estudiarán pruebas de consistencia, corrección y completud.

Se estudiará el cálculo de predicados, analizando los problemas de consistencia, completud y decidibilidad.

Se analizará el problema de la verdad y los modelos, y de los modelos e interpretaciones de teorías.

El procedimiento de evaluación será el de la presentación de tareas por escrito y de exámenes parciales y finales.

Evaluación: Examenes parciales y un examen final escrito.

SUGERENCIAS BIBLIOGRÁFICAS PARA LÓGICA I

Enderton, H. B., Una Introducción Matemática a la Lógica, IIF/UNAM, México, 1987.

van Fraassen, B., Semántica Formal y Lógica, IIF/UNAM, México, 1987.

Fraenkel, A., Teoría de los Conjuntos y Lógica, IIF/UNAM, México, 1976.

Mendelson, E., Introduction to Mathematical Logic, Nueva York, van Nostrand, 1979.

2.3 Teoria del conocimiento I

Se analizarán diversas concepciones sobre los conceptos de creencia y de conocimiento. Se discutirán diversas concepciones sobre la caracterización, justificación y aceptación del conocimiento. Se examinará el problema del conocimiento del mundo externo, así como el problema de la certeza. Se discutirá la noción de racionalidad, en relación con las razones para creer y el problema de la justificación de las creencias y del conocimiento. Se abordará el problema de si existen diversos tipos de conocimiento y el concepto de comunidades epistémicas.

La naturaleza y amplitud del tratamiento de estos problemas a lo largo de la historia de la filosofía y en la reflexión contemporánea, hace imposible establecer una bibliografía básica. A manera de ilustración, se propone la siguiente bibliografía.

Evaluación: Exámenes parciales y un examen final.

BIBLIOGRAFÍA

Ayer, A. (ed.), El Positivismo Lógico, Fondo de Cultura Económica, México, 1965.

Descartes, Rene, Meditaciones Metafísicas, (varias ediciones).

Foley, R., The Theory of Epistemic Rationality, Harvard University Press, Cambridge, Mass., y Londres, 1987.

Hume, David, Tratado sobre la Naturaleza Humana, (varias ediciones) Investigaciones sobre el Conocimiento Humano, (varias ediciones).

Kant, Immanuel, Crítica de la Razón Pura, (varias ediciones).

Kornblith, H., Naturalizing Epistemology, The MIT Press, Cambridge Mass., y Londres, 1985.

Leherer, K., Knowledge, Clarendon Press, Oxford, 1974.

Platón, Teeteto, (diversas ediciones).

Moser, P., Empirical Justification, Reidel, Dordrecht, 1985.

Polanyi, M., Personal Knowledge, University of Chicago Press, Chicago, Ill, 1958.

Russell, B., The Problems of Philosophy, 1912, reimpreso por Oxford University Press, Oxford, 1974.

Russell, B., Human Knowledge, Its Scope and Limits, Simon and Schuster, Nueva York, 1948.

Scheffler, I., Las Condiciones del Conocimiento, IIF/UNAM, México, 1973.

Sosa, E., Conocimiento y Virtud Intelectual, IIF/UNAM-FCE, México, 1992.

Villoro, L., Creer, Saber, Conocer, Siglo XXI Editores, México, 1982.

2.4 Historia de la ciencia I

Se estudiarán críticamente los aspectos más sobresalientes de la relación entre filosofía e historia de las ciencias, así como las principales historiografías contemporáneas de la ciencia. Se analizarán tendencias y casos de estudio de la ciencia en el renacimiento, la revolución científica y el surgimiento y la complejidad de la materia. El profesor deberá seleccionar cuidadosamente los episodios científicos y las ideas científicas y filosóficas que se analicen. Entre otras, se discutirán algunas de las ideas centrales de Bacon, Vesalio, Copérnico, Kepler, Galileo, Harvey, Newton, Lagrange, Buffon, Lavoisier, Priestley, Cavendish, Coulomb, Boyle, Hooke y la revolución darwiniana.

Los cursos en historia de la ciencia utilizarán fuentes primarias. Se harán accesibles a los estudiantes las reproducciones de (las partes de) los trabajos originales que se estudiarán en el curso.

Algunos títulos de fuentes secundarias que podrían utilizarse en los cursos en historia de la ciencia son los siguientes (por supuesto la bibliografía posible es enorme, los títulos que se señalan a continuación son meramente indicativos de la bibliografía secundaria que podrían estudiar los alumnos):

Evaluación: Examenes parciales y un examen final escrito.

BIBLIOGRAFÍA

Bell, A., Newtonian Science, Londres, E. Arnold Ltd, 1961.

Boas, M., The Scientific Renaissance, 1450-1630. Harper and Brothers, New York, 1962.

Buchdahl, G., Metaphysics and the philosophy of Science: the Classical Origins. Descartes to Kant, Oxford, Blackwell, 1969.

Bullough, V. L., The Scientific Revolution, Nueva York, Holt, Rinehart and Winston, 1970.

Butterfield, H., Los orígenes de la ciencia moderna, México, CONACYT, 1981.

Cohen, I. B., The Newtonian Revolution, Cambridge University Press, 1980.

Cohe, I. B., Revolutions in Science, Cambridge, Harvard University, 1985.

Crombie, A. C., Historia de la Ciencia: de San Agustín a Galileo, Alianza Editorial, Madrid, (2 vols.), 1959.

Dampier, W. C., A History of Science and Its Relations with Philosophy and Religion. Cambridge University Press, Cambridge, (4a. ed.), 1961.

Dampier, W. C., A Shorter History of Science, Meridian Books, Cleveland Press, 1966.

Drake, S., Galileo at Work. His Scientific Biography, The University of Chicago Press, 1978.

Farrington, B., The Philosophy of Francis Bacon. An Essay on its Development from 1603 to 1609, Liverpool University Press, 1964.

Gavroglu, K., Trends in the historiography of science, Kluwer, 1994.

Giere, "History and philosophy of science", British Journal for the philosophy of science, 1973.

Hall, A. R. y Hall, M. B., A Brief History of Science. New York, Signet Books, 1964.

Hall, A. R., From Galileo to Newton. 1630-1720. New York, Harper and Row, 1963.

Hall, A. R., The Scientific Revolution, 1500-1800. Boston, The Beacon Press, 1956.

Knigth, D., Sources for the History of Science. The Sources of History Ltd., Londres, 1975.

Koyré, A., Estudios de Historia del Pensamiento Científico, México, Siglo XXI, 1978.

Koyré, A., Newtonian Studies, Londres, 1965.

Laudan, L., Beyond positivism and relativism, 1995.

Manuel F. E., A Portrait of Isaac Newton´s Scientific Carrer, Cambridge, Mass.

Olhy, et. al., Companion to the history of modern science, The University of Chicago, 1990.

Shapere, D., Galileo, A Philosophical Study, The University of Chicago Press, 1974.

Schaffer, Gooding y Pineda (eds.), The uses of experiment, 1989.

Singer, C., The Discovery of the Circulation of the Blood, Londres, Dowson and Sons, 1956.

Taton, R. (editor), Historia General de las Ciencias: vol. II La Ciencia Moderna (de 1450 a 1800), Orbis, Barcelona, 1988.

Yates Frances, Giordano Bruno and the Hermetic Tradition, The University of Chicago Press, 1964.

Westfall, R. S., Never at Rest: A Biography of Isaac Newton, Cambridge University Press, 1980.

2.5 Filosofía de la ciencia II

En este curso se abordarán problemas de la dinámica de la ciencia, en especial el problema del cambio conceptual y del desarrollo científico. Se discutirán diversos modelos de desarrollo científico y la noción de racionalidad aplicada a estos modelos. Se discutirá también el problema del progreso en la ciencia y en la tecnología, así como la producción social del conocimiento científico.

Por la naturaleza del tema no es conveniente fijar una bibliografía, pero el profesor se asegurará que el alumno conozca y discuta los modelos de Popper, Kuhn y Lakatos, así como las principales críticas que se les han hecho desde diferentes perspectivas, especialmente las de Paul Feyerabend, Larry Laudan, Dudley Shapere y Wolfgang Stegmüller.

Evaluación: Examenes escritos (parciales y final).

BIBLIOGRAFÍA que se sugiere:

Agassi, J. y Jarvie, I. C. (eds.), Rationality: The Critical View, Martinus Nijhoff Publishers, Dordrecht, Holanda, 1987.

Campbell, D., "Evolutionary Epistemology", en Schilpp 1974, pp. 413-463.

Fayerabend, P., Contra el Método, Ariel, Barcelona, 1974.

Fayerabend, P., "Consuelos para el especialista", en Lakatos y Musgrave 1970.

Fayerabend, P., Límites de la Ciencia, Paidós, Barcelona, 1989.

Garber, D., "Learning from the past: reflections on the role of history in the philosophy of science", en Synthese 67, pp. 91-114, 1986.

Hacking, I. (ed.), Scientific Revolutions, Oxford University Press, Oxford, 1981.

Hesse, M., Revolutions and Reconstructions in the Philosophy of Science, Harvester Press, Brighton, 1980.

Hull, D., Science as a Process, The University of Chicago Press, Chicago y Londres, 1988.

Kuhn, T., The Structure of Scientific Revolutions, 2a. ed. aumentada, The University of Chicago Press, Chicago, 1970. (La Estructura de las Revoluciones Científicas, F.C.E., México, la. ed. 1971), 1962.

Kuhn, T., "¿Lógica del descubrimiento o psicología de la investigación?, en Lakatos y Musgrave 1970 a.

Kuhn, T., "Consideración en torno a mis críticos", en Lakatos y Musgrave, 1970 b.

Kuhn, T., "Notas sobre Lakatos", en Lakatos y Musgrave, 1970 c.

Kuhn, T., The Essential Tension, The University of Chicago Press, Chicago, 1977. (La tensión Esencial, CONACYT/FCE, México, 1a. ed. 1982)

Kuhn, T., "Second Thoughts on Paradigms", en Suppe 1977 a, pp. 459-499.

Kuhn, T., What are Scientific Revolutions?, Massachusetts Institute of Technology, Cambridge y Londres, 1987. (¿Qué son las revoluciones científicas?, Paidós/ICE de la Universidad Autónoma de Barcelona, Barcelona- Buenos Aires-México, 1989).

Lakatos, I. y Musgrave, A. (eds.), La Crítica y el Desarrollo del Conocimiento, Trad. de Francisco Hernán de la 2a. ed. inglesa y aumentada con Lakatos 1971 y Kuhn 1970c, Grijalbo, Barcelona-Buenos Aires-México, 1975. (Criticism and the Growth of Knowledge, 2a. ed., Cambridge University Press, Londres, 1972).

Lakatos, I., "La falsación y la metodología de los programas de investigación científica", en Lakatos y Musgrave 1970.

Lakatos, I., "La historia de la ciencia y sus reconstrucciones racionales", en Lakatos y Musgrave 1970. (la. ed. del original en inglés, Boston Studies in Philosophy of Science, Vol. VIII, Dordrecht 1971, pp. 91-136.

Laudan, L., Progress and its Problems, University of California Press, Berkeley and Los Angeles, 1977.

Laudan, L., Science and Values, University of California Press, Berkeley, 1984.

Laudan, L., "Some problems facing intuitionist meta-methodologies", en Synthese 67, 1986, pp. 115-129, 1986.

Laudan, L., "Progress or rationality? The prospects for normative naturalism", en American Philosophical Quarterly, Vol. 24, No. 1, 1987, pp. 19-31.

Martínez, S., "Método, evolución y progreso en la ciencia" en Crítica, 25 (73), 1993.

Olivé, L. (comp.), La Explicación Social del Conocimiento, IIF/UNAM, México, 1985.

Popper, K., "La ciencia normal y sus peligros", en Lakatos y Musgrave, 1970.

Pérez Ransanz, A. R., "Modelos del cambio científico" en U. Moulines (coord.), Enciclopedia Iberoamericana de Filosofía, Trotta, Madrid, 1994.

Sarkar, H., "Imre Lakatos, meta-methodology: an appraisal", en Philosophy of the Social Sciences 10, 1980, pp. 397-416.

Schilpp, P. (ed.), The Philosophy of Karl Popper, Open Court, La Salle, Ill, 1974.

Shapere, D., Reason and the Search for Knowledge, Reidel Publishing Co., Dordrecht, 1984.

Shapere, D., "Objectivity, Rationality and Scientific Change", en P. Kitcher y P. Asquith (eds.), PSA 84, Vol. II, 1986.

Toulmin, S., "La distinción entre ciencia normal y ciencia revolucionaria ¿resiste un examen?", en Lakatos y Musgrave, 1970.

Toulmin, S., Human Understanding, Princeton University Press, Princeton, New Jersey. (Trad. La Comprensión Humana, Alianza Universidad, Madrid, 1977).

Wykstra, S., "Toward a Historical Meta-Method for Assessing Normative Methodologies: Rationality, Serendipity and the Robinson Crisoe Fallacy", en PSA 1980, Vol. 1, pp. 211-222.

2.6 Lógica II

Se estudiarán temas y problemas fundamentales de la lógica inductiva y se centrará en dos temáticas: lógica de la probabilidad (especialmente bayesiana) y la estructura de argumentos estadísticos).

Evaluación: Examenes escritos (parciales y final).

BIBLIOGRAFÍA

Campbel, D., Experimental and Quasi-Experimental Designs for Research, Boston, Houghton, Mifflin, 1996.

Earman, John., Inference, explanation, and other Philosophical Frustations: Essays in the Philosophy of Science, Berkeley, Univ. of California Press, 1992.

Hacking, I., Logic of statistic Inference, Cambridge Univ. Press, 1965.

Hesse, M., Structure of Scientific Inference, London, McMillan, 1974.

Howson, Colin and Peter Urbach, Scientific Reasoning. The Bayesian Approach, Chicago, Open Court, 1993.

Jeffrey, Richard, Probability and the Art of Judgment, Cambridge Univ. Press, 1992.

Salmon, W., Foundation of Scientific inference, Univ. of Pittsburgh Press, 1967.

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Universidad Nacional Autónoma de MéxicoFacultad de Filosofía y LetrasInstituto de Investigaciones FilosóficasPosgrado en Filosofía de la CienciaCiudad Universitaria, Coyoacán, México, D.F.

London Centre for the History of Science, Medicine and TechnologyMSc in History of Science, Medicine and Technology

OPTION: PHILOSOPHY OF SCIENCESecond and third terms, 2003-04Thursdays 10.30am-12.30pmSeminar Rooms 1 & 2, second floor, Euston House (Wellcome Trust Centre)

Dr Hasok ChangDept of Science and Technology StudiesUniversity College LondonGower Street, London WC1E 6BT

Office: 22 Gordon Square, room 3.2Telephone: 7679-1324 (office), 8341-6710 (home)E-mail: h.chang@ucl.ac.ukOffice hours: to be announced.

AIMS OF THE COURSEThis course addresses some fundamental questions about the nature and development of scientific knowledge, including the following:

• What differentiates science from other systems of thought and ways of engaging with the natural world? Is there a "scientific method" that guarantees the superiority and reliability of scientific knowledge? • Is there progress in science, or merely change from one worldview to another, each maintained by social agreement? Do scientists choose between competing theories in a rational way? • What is the relationship between observation, experimentation and theory? • Does science give us an objectively true description of an independent physical reality, or useful tools of thought, or both?

This course is an introduction to the philosophy of science specifically designed for historians. All of the philosophical questions will be addressed through concrete episodes from the actual development of science. Historiographical issues will also continually arise from these philosophical debates. In both of those ways, connections will be made with the content of the rest of the MSc programme.

The work in this course is also designed to get you into the general habit of thinking and writing clearly and precisely about any issues you consider.

ASSESSMENTAssessment is by two essays of 5,000 words each, and a written exam at the end of the course. I will make suggestions on essay topics, but the crafting of the question is ultimately your own task. Common essay deadlines will apply, with standard penalties for lateness (2 points per day). Further guidance will be provided on the exam in due course.

LOCATION OF READING MATERIALS

Most reading materials needed for this course are available in the UCL Libraries. Please note that the philosophy of science materials are split between the Science Library (mostly under History of Science) and the Main Library (mostly under Philosophy). Many heavily used books can be found in the Science Library Short Loan Collection, and some photocopied materials in the Teaching Collection (request these at the Issue Desk). Many of the important texts are also available in the Science Museum Library, the Wellcome Trust Library and the Senate House (University of London) Library. A number of sources, particularly journal articles, are also available electronically through the UCL Library.

Location Code for Reading Materials (see the end of each item below):SL: Some or all copies of a book in the Science Library Short Loan Collection

(3-hour loan or 2-day loan).TC: Photocopy in the Science Library Teaching Collection (3-hour loan);

request at the Issue Desk, quoting the four-digit reference number given in the catalogue (eUCLid).

ELEC: Electronically available; further details about access will be given.HC: Not easily available; consult the tutor in case of difficulty.If no indication is given, the book or periodical is easily available on standard

loan from the UCL Libraries.

SCHEDULE OF SESSIONS AND READINGS** Lists of further recommended readings are available separately for individual topics.

The Structure of the Sessions: At the end of each session, I will give a brief lecture introducing the topic designated for the following week. Then you should do the assigned reading for that topic before the next session, at which we will examine it in more depth, in a discussion format as much as possible. Therefore it is essential that you do the reading listed under each session before coming to class.

As a backup text that gives an accessible introduction to many of the key issues we will be discussing, I recommend Alan F. Chalmers, What Is This Thing Called Science?, 3rd ed. (Buckingham: Open University Press, 1999); the second edition can also be used. Also recommended is Martin Curd and J. A. Cover, Philosophy of Science: The Central Issues (New York and London: Norton, 1998), an anthology containing a number of classic readings and some helpful commentary on them; several of the readings below are contained in Curd and Cover, in which case an indication is given. Both books are available for purchase in major bookshops, and there are multiple copies of each, including some on short loan, in the UCL Libraries.

PART A. INTRODUCTION: THE NATURE OF SCIENTIFIC KNOWLEDGE

1. What is science? Popper vs. the inductivists (22 January 2004)• Karl Popper, Conjectures and Refutations, 3rd ed. (London: Routledge, 1969), pp. 33-41 (sections 1.i-1.iii); you may use other editions. Read the rest of chapter 1 if possible. Also reprinted in Curd and Cover, pp. 3-10. SL

Also recommended:• A. F. Chalmers, What Is This Thing Called Science?, 3rd ed. (Buckingham: Open University Press, 1999), chs. 1, 4, 5.• Paul Arthur Schilpp, ed., The Philosophy of Karl Popper (La Salle: Open Court, 1974).

2. Paradigms and revolutions (29 January 2004)• Thomas S. Kuhn, The Structure of Scientific Revolutions, 2nd ed. (Chicago: University of Chicago Press, 1970), pp. 10-51, 92-135 (chs. 2-5, 9-10); do not use the first edition (1962); the third edition is essentially the same as the second. SL• Paul Feyerabend, "How to Defend Society Against Science", Radical Philosophy, no. 11 (1975), pp. 3-8; reprinted in E. D. Klemke, Robert Hollinger, and A. David Kline, eds., Introductory Readings in the Philosophy of Science, revised ed. (Buffalo: Prometheus Books, 1988), pp. 34-44. SL (Klemke et al.), TC (photocopy)Also recommended:• Thomas S. Kuhn, "Objectivity, Value Judgment, and Theory Choice", in The Essential Tension (Chicago: University of Chicago Press, 1977), pp. 320-339.• Imre Lakatos and Alan Musgrave, eds., Criticism and the Growth of Knowledge (Cambridge: Cambridge University Press, 1970).

3. Progress and rationality (5 February 2004)• Imre Lakatos, "Science and Pseudoscience", in Philosophical Papers, vol. 1 (Cambridge: Cambridge University Press, 1977), pp. 1-7. Also reprinted in Curd and Cover, pp. 20-26.• Paul Thagard, "Why Astrology Is a Pseudoscience", in P. Asquith and I. Hacking, eds., Proceedings of the Philosophy of Science Association 1978, vol. 1 (East Lansing, Mich.: Philosophy of Science Association, 1978), pp. 223-234. Also reprinted in Curd and Cover, pp. 27-37. ELEC, SLAlso recommended:• Brendan Larvor, Lakatos: An Introduction (London: Routledge, 1998).• Imre Lakatos, "Criticism and the Methodology of Scientific Research Programmes", Proceedings of the Aristotelian Society, vol. 69 (1968-69), pp. 149-186. TC.• C. Howson, ed., Method and Appraisal in the Physical Sciences (Cambridge: Cambridge University Press, 1976). This is a collection of historical case studies carried out in the Lakatosian framework, including Musgrave's paper on oxygen and phlogiston.

PART B. THE CHALLENGE OF SCIENTIFIC OBSERVATION

4. Reality, appearance, and artifacts (12 February 2004)• Nicolas Rasmussen, "Facts, Artifacts, and Mesosomes: Practicing Epistemology with the Electron Microscope", Studies in the History and Philosophy of Science, vol. 24 (1993), pp. 227-265.Also recommended:• Alan Chalmers, "The Theory-Dependence of the Use of Instruments in Science", Philosophy of Science, vol. 70 (2003), pp. 493-509.• James Bogen and James Woodward, "Saving the Phenomena", Philosophical Review, vol. 97 (1988), 302-352.

UCL Reading Week (16-20 February 2004): There will be no lecture on 19 February; start working on the first essay.

5. Inference and observation (26 February 2004)• Dudley Shapere, "The Concept of Observation in Science and Philosophy", Philosophy of Science, vol. 49 (1982), pp. 485-525. ELEC

Also recommended:• Trevor Pinch, Confronting Nature: The Sociology of Solar-Neutrino Detection (Dordrecht: Reidel, 1986).• Peter Kosso, "Dimensions of Observability", British Journal for the Philosophy of Science, vol. 39 (1988), pp. 449-467.

6. Operationalism (4 March 2004)• Percy W. Bridgman, The Logic of Modern Physics (New York: Macmillan, 1927), pp. 1-32 (ch. 1). HC• Carl Hempel, Philosophy of Natural Science (Englewood Cliffs: Prentice-Hall, 1966), pp. 85-100 (ch. 7). SLAlso recommended:• Philipp G. Frank, ed., The Validation of Scientific Theories (New York: Collier Books, 1961), pp. 45-92 (ch. 2). • Maila L. Walter, Science and Cultural Crisis: An Intellectual Biography of Percy Williams Bridgman 1882-1961 (Stanford: Stanford University Press, 1990).

7. Measurement and convention (11 March 2004)• Henri Poincaré, "The Measure of Time", in The Foundations of Science, trans. by G. B. Halsted (Lancaster, Pa.: The Science Press, 1946), pp. 223-234. Also reprinted in A. B. Arons and A. M. Bork, eds., Science and Ideas (Englewood Cliffs, N.J.: Prentice-Hall, 1964), pp. 37-48. Also in Henri Poincaré, The Value of Science (New York: Dover, 1958). HCAlso recommended:• David Landes, Revolution in Time: Clocks and the Making of the Modern World (Cambridge: Harvard University Press, 1983).• Peter Galison, Einstein's Clocks, Poincaré's Maps: Empires of Time (New York: Norton, 2003), ch. 4.

PART C. THE ACTIVE VIEW OF KNOWLEDGE

8. Representation vs. intervention (18 March 2004)• Ian Hacking, Representing and Intervening (Cambridge: Cambridge University Press, 1983), pp. 149-209 (ch. 9, 10, 11). SLAlso recommended:• Paul M. Churchland and Clifford A. Hooker, eds., Images of Science, pp. 297-300 (reply from Bas van Fraassen on Hacking's paper on microscopes).• David B. Resnik, "Hacking's Experimental Realism", Canadian Journal of Philosophy, vol. 24 (1994), pp. 395-412.• Dudley Shapere, "Astronomy and Anti-Realism", Philosophy of Science, vol. 60 (1993), 134-150.

• Allan Franklin, "Experiment in Physics", 24pp, in the Stanford Encyclopedia of Philosophy, online at http://plato.stanford.edu• David Gooding, Trevor PInch, and Simon Schaffer, eds., The Uses of experiment: Studies in the Natural Sciences (Cambridge: Cambridge University Press, 1989).

9. Skills and rule-following (25 March 2004)• Michael Polanyi, Personal Knowledge: Towards a Post-Critical Philosophy (Chicago: University of Chicago Press, 1958), pp. 49-65 (ch. 4).• Ludwig Wittgenstein, Philosophical Investigations, 3rd ed., trans. by G. E. M. Anscombe (New York: Macmillan, 1968[?]), §§66-87 and §§142-255 (pp. 31-41, 56-61).Also recommended:• Harry Collins, Changing Order: Induction and Replication in Scientific Practice (London: Sage, 1985).• J. N. Findlay, Wittgenstein: a Critique (London: Routledge & Kegan Paul, 1984), esp. ch. 7.• Thomas A. Langford and William H. Poteat, Intellect and Hope: Essays in the Thought of Michael Polanyi (Durham, N.C.: Duke University Press, 1968). Senate House; HC.• Stafania Jha, Reconsidering Michael Polanyi's Philosophy (Pittsburgh, Pa.: University of Pittsburgh Press, 2002).• Richard Gelwick, The Way of Discovery: An Introduction to the Thought of Michael Polanyi (New York: Oxford University Press, 1977).

FIRST ESSAY due on Friday 26 March 2004

EASTER BREAK: 29 March to 26 April 2004

PART D. ONTOLOGY, EXPLANATION, AND EPISTEMOLOGY

10. The vitalism debate: mechanism vs. teleology (29 April 2004)• Hans Driesch, "Experimental Morphogenesis", in The Science and Philosophy of the Organism (London: Adam and Charles Black, 1908), pp. 56-70. TC=SCIENCE 4288.• Hans Driesch, "The Empirical Proofs of Vitalism", in The History and Theory of Vitalism, trans. by C. K. Ogden and revised for the author for the English edition (London: Macmillan, 1914), pp. 207-215. TC=SCIENCE 4286.• Henri Bergson, "Evolution of Life-mechanism and Teleology", in Creative Evolution, trans. by Arthur Mitchell (London: Macmillan, 1911), pp. 64-102. TC=SCIENCE 4301.Also recommended:• Ernest Nagel, The Structure of Science (New York: Harcourt, Brace and World, 1961), pp. 398-446 (ch. 12).• Frederick Burwick and Paul Douglass, eds., The Crisis in Modernism: Bergson and the Vitalist Controversy (Cambridge: Cambridge University Press, 1992).• Anne Harrington, Reenchanted Science: Holism in German Culture from Wilhelm II to Hitler (Princeton: Princeton University Press, 1996).

• Moritz Schlick, Philosophy of Nature, trans. by Amethe von Zeppelin (New York: Philosophical Library, 1949), Ch. 14-16.• Timothy O. Lipman, "Vitalism and Reductionism in Liebig's Physiological Thought", ISIS, Vol. 58 (1967), pp. 167-185.

11. Truth, explanation, and the aims of science (6 May 2004)• Nancy Cartwright, How the Laws of Physics Lie (Oxford: Clarendon Press, 1983), pp. 54-73 (ch. 3). • Nancy Cartwright, The Dappled World: A Study of the Boundaries of Science (Cambridge: Cambridge University Press, 1999), pp. 1-34 (introduction and ch. 1).Also recommended:• Michael Friedman, "Explanation and Scientific Understanding", Journal of Philosophy, vol. 71 (1974), pp. 5-19.• Philip Kitcher, "Explanatory Unification", Philosophy of Science, vol. 48 (1981), 507-531.

PART E. THE DYNAMICS OF BELIEF

12. The rejection of successful ideas (13 May 2004)• Carl Hempel, Philosophy of Natural Science (Englewood Cliffs: Prentice-Hall, 1966), pp. 3-18 (ch. 2). SL• Donald Gillies, "Hempelian and Kuhnian Approaches in the Philosophy of Medicine" (unpublished manuscript). HC• NOTE: Donald Gillies will be giving a public lecture on this subject at UCL on Monday 10 May at 5pm.Also recommended:• Naomi Oreskes, "The Rejection of Continental Drift", Historical Studies in the Physical Sciences, vol. 18, no. 2 (1988), pp. 311-348.• Larry Laudan, "A Confutation of Convergent Realism", Philosophy of Science, vol. 48 (1981), pp. 19-49, esp. sections 1, 2, 5, and 8. Also reprinted in Curd and Cover, pp. 1114-1135 ELEC, SL

13. The virtue of tenacity (20 May 2004)• Paul Feyerabend, Against Method (London: New Left Book, 1975), pp. 55-108 (chs. 5-9). Later editions may be used, but chapter numbers vary from edition to edition; look for chapters that discuss the case of Galileo's defence of Copernicanism. HCAlso recommended:• Gerald Holton, "Subelectrons, Presuppositions, and the Millikan-Ehrenhaft Dispute", Historical Studies in the Physical Sciences, vol. 9 (1978), pp. 161-224. HC• Greg Bamford, "Popper and His Commentators on the Discovery of Neptune : A Close Shave for the Law of Gravitation?", Studies in History and Philosophy of Science, vol. 27 (1996), pp. 207-232.• Norwood Russell Hanson, "Leverrier: The Zenith and Nadir of Newtonian Mechanics", Isis, vol. 53 (1962), pp. 359-378.

14. Believing what one cannot observe (27 May 2004)• Michael Gardner, "Realism and Instrumentalism in 19th-Century Atomism", Philosophy of Science, vol. 46 (1979), pp. 1-34. ELEC

Also recommended:• Mary Jo Nye, Molecular Reality: A Perspective on the Scientific Work of Jean Perrin (London: Macdonald, 1972), esp. Ch. 1 (pp. 1-50). TC.• Allan Franklin, "Millikan's Published and Unpublished Data on Oil Drops." Historical Studies in the Physical Sciences, vol. 11 (1981), pp. 185-201.• Mary Hesse, The Structure of Scientific Inference (London: Macmillan, 1974), pp. 9-44 (Ch. 1).• A. F. Chalmers, What Is This Thing Called Science?, 3rd ed. (Buckingham: Open University Press, 1999), ch. 15; in the second edition, see ch. 13

SECOND ESSAY due on Monday 31 May 2004

PART F. SUMMARY AND METHODOLOGICAL REFLECTIONS

15. Philosophy, history, and historiography (3 June 2004)• Stephen Brush, "Should the History of Science be Rated X?", Science, vol. 183 (1974), pp. 1164-1172. ELEC• Thomas Kuhn, "The Trouble with the Historical Philosophy of Science", in The Road Since Structure, ed. by James Conant and John Haugeland (Chicago: University of Chicago Press, 2000), pp. 105-120. HCAlso recommended:• Roger H. Stuewer, ed., Historical and Philosophical Perspectives of Science (Minneapolis: University of Minnesota Press, 1970).• John Losee, Philosophy of Science and Historical Enquiry (Oxford: Clarendon Press, 1987).

Part of session 15 will also serve as a revision session for the exam.Exam week: 14-18 June

SOURCES FOR BACKGROUND AND GENERAL REFERENCE

Introductory Textbooks• A. F. Chalmers, What Is This Thing Called Science?, 3rd ed. (Buckingham: Open University Press, 1999), or 2nd ed. (St Lucia: University of Queensland Press, 1982). • Nicholas Everitt and Alec Fisher, Modern Epistemology: A New Introduction (New York: McGraw-Hill, 1995). • Rom Harré, The Philosophies of Science (Oxford: Oxford University Press, 1972). • Carl G. Hempel, Philosophy of Natural Science (Englewood Cliffs: Prentice-Hall, 1966). • Peter Kosso, Reading the Book of Nature (Cambridge: Cambridge University Press, 1992). • John Losee, A Historical Introduction to the Philosophy of Science, 3rd ed. (Oxford: Oxford University Press, 1993).• Alan Musgrave, Common Sense, Science and Scepticism: A Historical Introduction to the Theory of Knowledge (Cambridge: Cambridge University Press, 1993).

• Anthony O’Hear, An Introduction to the Philosophy of Science (Oxford: Clarendon Press, 1989). • Samir Okasha, Philosophy of Science: A Very Short Introduction (Oxford: Oxford University Press, 2002).

More Advanced General Texts in the Philosophy of Science• George Couvalis, The Philosophy of Science: Science and Objectivity (London: Sage, 1977). • Donald Gillies, Philosophy of Science in the Twentieth Century (Oxford: Blackwell, 1993). • Ernest Nagel, The Structure of Science (New York: Harcourt, Brace and World, 1961).• W. H. Newton-Smith, The Rationality of Science (London and New York: Routledge, 1981).• Alex Rosenberg, Philosophy of Science: A Contemporary Introduction (London: Routledge, 2000).

Useful Anthologies• Richard Boyd, Philip Gasper, and J. D. Trout, eds., The Philosophy of Science (Cambridge, Mass.: The MIT Press, 1991).• Martin Curd and J. A. Cover, eds., Philosophy of Science: The Central Issues (New York and London: Norton, 1998).• Arthur Danto and Sidney Morgenbesser, eds., Philosophy of Science (Cleveland: The World Publishing Company, 1960). • Herbert Feigl and Grover Maxwell, eds., Current Issues in the Philosophy of Science (New York: Holt, Rinehart and Winston, 1961).• E. D. Klemke, Robert Hollinger, and A. David Kline, eds., Introductory Readings in the Philosophy of Science, revised ed. (Buffalo: Prometheus Books, 1988). • Joseph J. Kockelmans, ed., Philosophy of Science: The Historical Background (New York: The Free Press, 1968).• Jarrett Leplin, ed., Scientific Realism (Berkeley and Los Angeles: University of California Press, 1984).• Robert Nola and Howard Sankey, eds., After Popper, Kuhn and Feyerabend: Recent Issues in Theories of Scientific Method (Dordrecht: Kluwer, 2000).• William R. Shea, ed., Revolutions in Science: Their Meaning and Relevance (Canton, Mass.: Science History Publications, 1988).• Roger H. Stuewer, ed., Historical and Philosophical Perspectives of Science (Minneapolis: University of Minnesota Press, 1970).• Ryan Tweeney, Michael Doherty and Clifford Mynatt, eds., On Scientific Thinking (New York: Columbia University Press, 1981).• Philip P. Wiener, ed., Readings in Philosophy of Science (New York: Charles Scribner's Sons, 1953). • Arthur Zucker, ed., Introduction to the Philosophy of Science (Upper Saddle River, N.J.: Prentice Hall, 1996).

Reference works• A Companion to the Philosophy of Science, ed. by W. H. Newton-Smith (Oxford: Blackwell, 2000).• Encyclopedia of Philosophy, ed. by Paul Edwards (New York and London: Macmillan and the Free Press, 1967).

• The Oxford Companion to Philosophy, ed. by Ted Honderich (Oxford: Oxford University Press, 1995). • The Pimlico History of Western Philosophy, ed. by Richard H. Popkin (London: Pimlico, 1999). First published as The Columbia History of Western Philosophy (New York: Columbia University Press, 1998). • Routledge Encyclopedia of Philosophy, ed. by Edward Craig (London: Routledge, 1998).

Bayesian Nets, Jon Williamsonhttp://personal.lse.ac.uk/willia11/jw.htm#philprob

INDUCTIVISM AND ITS DEFECTS

http://www.shef.ac.uk/~phil/courses/312/01inductiv.htm

George Botterill

Main Theme: Inductivism has been to modern philosophy of science as dualism is to the philosophy of mind — the mistaken picture we need to escape from.

Inductivism

Inductivism may sound, like all –isms, a rather grand and unfamiliar thing. But the term is intended as a label for a popular (or perhaps: once popular) conception of what scientific method consists in. The basic idea of inductivism is that scientific progress results from close, careful and accurate observation of the facts. That process of observation reveals (we hope, if we are lucky) certain regularities in natural phenomena. The scientist then moves by a process of inductive generalization from the observed regularities to the formulation of laws and theories. The laws and theories just are generalizations of the observed regularities. To make an inductive generalization is to move from the evidence that a certain sequence or pattern has been observed in many cases to the conclusion that the same pattern will hold for all similar cases.

It has been suggested that this account of scientific practice is both familiar and widely accepted, among scientists and non-scientists alike. Here, for example, are quotations from two philosophers of science, who are both setting up inductivism as a critical target. Chalmers’ book What Is This Thing Called Science? begins with the following passage:

“Scientific knowledge is proven knowledge. Scientific theories are derived in some rigorous way from the facts of experience acquired by observation and experiment. Science is based on what we can see and hear and touch, etc. Personal opinion or preference and speculative imaginings have no place in science. Science is objective. Scientific knowledge is reliable knowledge because it is objectively proven knowledge.”

Chalmers AF [1976], What Is This Thing Called Science?, p.1

And here is Errol Harris, outlining a perhaps slightly less crude inductivism:

"The popular conception of science, its methods, the reason for and the nature of its advance are somewhat as follows. Whereas other types of human speculation are based upon mere opinion, science pursues and sticks to the facts. These facts are ascertained by direct observation – by sense-perception – and they supply the scientist with his data. He collects as large a mass of data as he can, classifies them and proposes hypotheses to explain their nature and occurrence, which can then be tested by further observation and by experiments devised to render specific observations more precise, more selective and more easily obtainable. The outcome of this method is a body of scientific laws, systematically related to one another, by reference to which the phenomena investigated can be explained."

Harris E [1970], Hypothesis and Perception, p.19

Such is the thinking that underlies the inductivist view of science. True, these two quotations are taken from writers who then go on to attack the inductivist view. But that is understandable, since it is widely believed (in particular as a result of the influence of Popper’s work) that inductivism has been exposed to a devastating critique in the philosophy of science. Before going on to outline that critique, it would be as well to see what the main credentials of this theory of science are. How influential has inductivism been? And what were the reasons for its appeal?

There is not much doubt that inductivism, in some form or another, has been very influential, at least from the time of Isaac Newton. Newton himself wrote that ‘the whole business of natural philosophy is to reason from the phenomena’, and since by ‘to reason’ he seemed to mean ‘to reason inductively’ this appeared to represent an inductivist doctrine. Newton was not the first to advocate inductivism. The philosopher and politician Francis Bacon had done so early in the 17th century. But naturally Newton’s views carried the greatest authority with men of science. Where the great Newton led, others were bound to follow, and that influence was lasting, both in actual scientific practice and in the philosophical and common-sense conceptions of science.

For example, Charles Darwin published his epoch-making book The Origin of Species in 1859. But he had worked out the basic argument in favour of his theory of evolution by natural selection some twenty years before. In the meantime he had accumulated a tremendous amount of empirical evidence in favour of his theory. In this he was certainly prompted by the idea that inductive support was required to make his theory respectable. He would have liked to have been able to present the theory as a conclusion derived inductively from the evidence. But that is not the way in which he actually arrived at his theory, and this is one instance in which the desire to accumulate inductive support could certainly have hampered scientific progress. (There were, admittedly,

other factors at work. For one thing, Darwin was apprehensive of the notoriety that publication would bring. In the end he published in something of a rush, because in the meantime Alfred Wallace had independently arrived at the theory of natural selection.)

The familiarity of the inductivist image of science is in itself testimony to the profound impact that it has had on common sense and the popular image of science. In the meantime philosophers have been greatly perturbed by ‘the Problem of Induction’. This is the problem of justifying the process of generalization by which, according to the inductivist, the scientist reasons from what has been observed to be the case both to what will be the case and also to what is always, invariably the case. The problem of induction was first posed by David Hume in the 18th century, and to this day no fully satisfactory solution to the problem has been found. To some this seemed a very serious matter. For science has been regarded as the supreme achievement of human reason. On the inductivist model science was entirely based upon inductive reasoning. So if inductive reasoning could not be rationally justified, it seemed that the very nerve-centre of human reason was tainted with irrationality. This reflection caused something like despair in certain thinkers. (The situation for empiricists in relation to the problem of induction was rather like that in which the followers of Pythagoras, those devotees of mathematical understanding, found themselves in with regard to that awkward number, the square root of 2.) This attitude is, for example, prominent in the epistemological work of Bertrand Russell. He was too resilient a spirit to be reduced to despair for long, but he did hold that a purely empiricist philosophy could not be fully satisfactory, because our empirical knowledge of the world was founded upon an inductive principle which could not itself be derived from experience.

Of the reasons for the appeal of inductivism, perhaps the principal one was that it was thought the great flowering of science in the 17th century was due to the adoption of an inductive approach. Perhaps you have heard the Italian philosopher–scientist Galileo Galilei, one of the main movers of the scientific revolution, portrayed as a man who appealed to direct observation of the facts, as against the wild and fanciful theories that had been prevalent in the past (thanks to the stultifying influence of the bad old Aristotelian philosophy). That, at least, used to be the “nutshell account”.

But it really is a travesty of how Galileo himself actually argued and debated. For instance, there is a story that Galileo demonstrated his law of falling bodies by dropping different sorts of objects from the top of a tower, thus ‘proving’ that the acceleration of a falling body due to gravity was independent of its constitution. But it is very doubtful whether Galileo ever carried out such an experiment: we have no firm historical evidence that he did. On the other hand, this is certain: if he had done so, then he would have learnt nothing of any use from it at all. Indeed, since the law of falling bodies only strictly holds in a vacuum, naive experiments are more likely to seem to count against it, than to confirm it. When astronauts finally reached the moon, they were able to conduct the experiment and confirm the law – a feather and a steel hammer really did fall at the same rate!

What Galileo himself actually said, in several places in the Dialogue Concerning the Two Chief World Systems, is that he did not need to conduct such tests, because he knew in advance, by mathematical reasoning, what their results must be. And in fact, as we shall see later in the course in discussing thought-experiments, Galileo actually argued that the rate at which unsupported objects fall is independent of their ‘heaviness’ by constructing a thought-experiment. (So much for relying on direct observational experience! It is interesting to compare his attempt to determine the round-trip velocity of light, an experiment he really did conduct, by unveiling lanterns on distant mountain tops.)

However, there are areas in which the inductive approach could be fruitful, even if mistaken as a general model of scientific method. Inductivism relies upon an appeal to the authority of the facts. Historically, there was a time when scientists needed the support of such a high authority as the facts, as nature itself. Remember that Galileo was forced by the Inquisition to recant his astronomical views because, according to the theologians of the day (1632), they were inconsistent with Holy Scripture. At that time science was very much subordinate to theology, so that from an historical perspective a strident inductivism can be seen as part of a drive towards intellectual independence on the part of scientists.

Then again, there are phases in scientific investigation in which what is required is a sort of preliminary spade-work, involving surveying, collecting specimens, and classifying the phenomena. This was surely the case in the biological sciences in the 17th and 18th centuries, for example; the more particularly in view of the multitude of new flora and fauna discovered in parts of the world that were then being explored by Europeans for the first time. Before Darwin it was necessary that there should first come the Swedish classifier and taxonomist Linnaeus (Carl Linné).

Before proceeding to the case against inductivism, there are a couple of important notes or warnings that need to be inserted. The first is that there is a danger of thinking that science is just one great movement that progresses like a vehicle travelling towards its destination. This is not the way things are, even though some (notably Auguste Comte and certain logical positivists) have seen it as an objective – the objective of unified science, in which all scientific subjects would be united by being integrated within a hierarchy in which subordinate laws were reduced to a small set of absolutely fundamental natural laws. In practice, however, some sciences are more theoretical, others more experimental, others mainly observational and collative. Why should we assume that there can be a single philosophy of science, a single theory of scientific rationality that will cover all these different areas and disparate concerns? Is it really plausible that there should be such a thing as the scientific method, equally applicable to the practicalities of soil science and the speculations of cosmology? Perhaps there are

some areas of science that inductivism fits, and others that it does not. [Philosophers of science have been almost exclusively interested in the most theoretical reaches of science – frontiers of physics, chemistry and cosmology. They tend not to pay so much attention to (say) meteorology or geology.]

The second point is that the nature of inductivism depends upon what one takes induction, as a method of reasoning, to consist in. Standard critiques of inductivism take the induction involved to be induction by simple enumeration. It certainly is pretty clear that this pattern of reasoning on its own is too impoverished to constitute the main process of scientific thinking. Not everyone thinks of induction as consisting solely in the pattern of inference by enumerative induction. Not surprisingly, the more relaxed one is about what can count as inductive reasoning, the more plausible inductivism becomes. More plausible, but also less distinctive as a methodological position. Some writers have suggested that we should call any inference to the best explanation an induction. If we do that, then I suppose we are all inductivists. But it is questionable whether we should allow that degree of latitude to inductive inference. Since there is quite widespread disagreement over what the criteria for a good explanation are, there is a danger that taking inductive inference to be inference-to-the-best-explanation may only result in making it unclear what is and what is not a warranted inductive inference.

To summarise, we can at any rate say that inductivism does have a certain appeal. It stresses that we should base our theories very firmly upon observations; indeed, upon a large number of carefully and accurately made observations, and upon observations that have been made in as wide a variety of conditions as possible. Now, what is wrong with that as an account of scientific method? You might think that it is a pretty unexciting and vague account, and could be improved by refinement and added detail. But surely it could not be very badly wrong? And yet, in the view of a number of highly influential philosophers of science, inductivism is totally incorrect and completely misleading. To the Popperians, and others who have been impressed by Popper’s writings, inductivism is absolute anathema. So let us turn now to what have been seen as the defects of inductivism.

THE DEFECTS OF INDUCTIVISM

· The Problem of Induction

The philosophical problem of induction is the problem of explaining why it is that inductive inference is a rational procedure. Why should the fact that certain sequences of events have always followed each other in our past experience provide a reason for believing that the same sequences will occur again in the future? Or in all similar circumstances – past, present and future, here and everywhere else in the universe? Since inductivism relies upon inductive generalization (from particular instances to

general laws) as the main process of scientific reasoning, it is clear that if we are inductivists about scientific method we will have to take the problem of induction seriously.

**Note well: However, although this is a popular objection, I doubt whether this can fairly be described as a defect of inductivism. After all, perhaps we do have to take the problem of induction seriously anyway, whether we are inductivists or not. Attempts to dispense with inductive inference altogether are, as we shall see, pretty implausible. Taking Hume’s Problem of Induction as the main problem for inductivism is, what’s more, quite definitely a big mistake. To see this, consider an analogy with vegetarianism. Now vegetarianism may well be inadequate as a diet, just as inductivism seems inadequate as a method of theory-formation. But what’s wrong with vegetarianism isn’t that it involves eating vegetables! And the best way of reforming vegetarianism (assuming it’s in need of any reform) isn’t to give up eating vegetables altogether — even though Popper seems to advocate something very like this!**

· Inductivism’s Incorrect View of Observation

According to inductivism scientific progress is a movement from observation, via inductive generalization, to general law-like principles. There are two main objections to this idea:

(i) It suggests that scientific observation can begin in a sort of pre-theoretical vacuum. But without some theoretical questions to be resolved how can a scientist tell what is worth observing? [Note Darwin’s dictum: ‘every important observation is either for or against some theory’.]

(ii) It presupposes that observation gives us direct access to the facts in a way that does not involve any prior theorizing. Against this it has been argued by a number of philosophers of science (e.g., Hanson, Kuhn, Feyerabend) that ‘all observation is theory-laden’. Perhaps they overstate their case (surely some observations carry a heavier theoretical load than others). But certainly many observational results will presuppose theories – e.g., as to how various instruments work, how various forces and quantities can be measured.

· Inductivism’s Incorrect Account of History of Science

No simple summary is possible under this heading beyond remarking that a common refrain in recent history and philosophy of science has been to take some episode in the

history of science and show that it cannot be adequately understood as an instance of inductivist methodology at work

· Inductivism’s Incorrect Account of Theorizing

The point is that inductive generalization may enable one to discover regularities or general connection between phenomena, but it simply does not have the resources to produce genuinely explanatory theories. This is a consequence of the fact that in enumerative induction you cannot have predications in the conclusion that do not appear in the premises (observational data). Consider, for example, the experimentally discoverable connections between the pressure, volume and temperature of a gas, or the observed phenomenon of industrial melanism, and theoretical explanations of why gases behave in this way, why species change their colour.

[**This seems to me the single most serious defect of inductivism – far more damaging than the problem of justifying inductive inference (which is arguably a problem for everybody).**]

· The Context of Discovery v the Context of Justification

The objection under this heading is that inductivism is proposing the wrong sort of scientific method – a sort of recipe for arriving at laws and theories. Against this it has been urged (particularly forcefully by Popper) that how a particular hypothesis or theory comes to be considered is not really relevant to its scientific status. That is part of the context of discovery. As such, it may be of historical or psychological interest, like the incident of an apple (supposedly) falling on Newton’s head. But such episodes which prompt or inspire theoretical thought are not really of any methodological significance. What matters is the way in which a hypothesis or theory is tested and assessed after it has been proposed (the context of justification).

· The Superiority of Hypothetico-Deductivism

Finally, inductivism seems less satisfactory than a hypothetico-deductive model of science, according to which testable consequences are deduced from theoretical hypotheses – if only because any proposed illustration of inductivism at work can equally be taken as an instance of hypothetico-deductivism. In that case it does not seem to matter very much whether we say that the hypotheses have been arrived at by a process of inductive generalization (inference from the phenomena) or that the hypotheses have been suggested by an observed regularity (with the dea that there is a law being prompted by observation). Either way, the proposed law or theory will have to stand up to further testing of its consequences. So hypothetico-deductivism seems to trump inductivism. Any scientific development inductivism can account for, hypothetico-deductivism can also account for — but not vice versa!

Suggested Reading

Chalmers, AF What Is This Thing Called Science, chs.1-3

Hanson, NR Patterns of Discovery, ch.4, pp.70-92

Harman, G ‘The inference to the best explanation’, Philosophical Review LXXIV, 1965, pp.88-95

Harré, HR The Philosophies of Science, ch.2, pp.34-61

Popper, KR ‘Conjectural knowledge: my solution to the problem of induction’ in his Objective Knowledge

Popper, KR The Logic of Scientific Discovery, ch.X, pp.251-81

DEPARTMENT OF PHILOSOPHY Level 3 Module

PHI 312 : PHILOSOPHY OF SCIENCE

MODULE SYLLABUS

Timetable: Monday 3-4 in 11.1; Thursday 12-1 and 2-3 in 11.31

LECTURER: George Botterill Office Hours Wed 1-2, Fri 1-2; external tel: 222 0580; email: g.botterill@sheffield.ac.uk

OUTLINE

This course will deal with general issues in the philosophy of science, with particular emphasis on the rationality of theory-change, explanation, the status of scientific laws, observation, and the structure of scientific theories. Most of the course will be devoted to the methodology of natural science; but some topics in the philosophy of the social sciences will also be discussed.

Natural Science:

The issues presented revolve around two major debates in the philosophy of science:

(1) the dispute between Kuhn and Popper about theory change

(2) disagreements between positivist and realist conceptions of science.

Modern philosophy of science has become closely linked with the history of science, and the course will reflect this by considering how well major developments in the history of science accord with methodological rules about how scientists ought to proceed. The Copernican Revolution in astronomy will be used as a specific case-study.

Social Science:

Here the most important general question is whether the methods and mode of explanation used in the natural sciences can also be applied to the study of society. This is sometimes referred to as the issue of naturalism: pro-naturalists maintaining (following in this John Stuart Mill in Book VI of his A System of Logic) that the study of society — social science — can be scientific in much the same way that the natural sciences are, whereas anti-naturalists offer various reasons why this can’t be so.

During this semester’s course we will only have time to fit in careful discussion of one major topic in the philosophy of the social sciences, namely:

• Popper’s Critique of Historicism

However, for those with a particular interest in social science, and in particular in the objectivity of social theory, a further topic — namely:

• Weber’s Doctrine of Wertfreiheit —

is available as an essay subject. (See the Coursework Summary for further details.)

AIMS AND OBJECTIVES

The main aims of the module PHI312 Philosophy of Science are:

· to introduce students to the debate about theory-change in science, deriving from the work of Popper, Kuhn, Feyerabend and Lakatos

· to help students acquire an understanding of some important problems in the philosophy of science (concerning such topics as: explanation, observation, scientific realism, and the nature of laws)

· to encourage students to enter into serious engagement with some of the major problems in the philosophy of science.

There is a great deal of material to be covered in this course. But then the philosophy of science is a large area, and one with many specialist brances (e.g. philosophy of biology, philosophy of physics, probability and confirmation theory) — some of which we must omit or discuss only in a limited way. But, most importantly, there are some difficult and unresolved problems (such as: How to judge the outcome of the Popper-Kuhn-Lakatos debate? or: Can we provide a general account of explanation? or: Is there an acceptable form of scientific realism?) that pose challenges which should stimulate students to active philosophical engagement in their own work.

GENERAL READING

Philosophy of science books are shelved in the Main Library in sections 140-143. There are two leading periodicals that you will probably wish to consult: Philosophy of Science and the British Journal for the Philosophy of Science (both to be found in Stack 4 at PER 105).

· Two of the best general guides through the philosophy of science are:

Chalmers, A.F. 3rd edn. 1999. What Is This Thing Called Science?. Open UP.

Newton-Smith, W.H. 1981. The Rationality of Science. Routledge.

· Two good survey articles, both written by David Papineau, are:

‘Methodology: The elements of the philosophy of science’, ch.3 in A.C. Grayling ed, Philosophy: a guide through the subject, Oxford UP: 1995

‘Philosophy of Science’, ch. 9 in N. Bunnin and E.P. Tsui-James ed, The Blackwell Companion to Philosophy, Blackwell: 1996.

· A short and lively introduction to the thinking of one of the most influential figures in 20th century philosophy of science:

Magee, B. 1973. Popper. Fontana.

· Modern classics:

Feyerabend, P.K. 1975. Against Method. New Left Books.

Kuhn, T.S. 1962. The Structure of Scientific Revolutions. Univ. of Chicago Press.

Popper, K.R. 1963; 5th edn.1989. Conjectures and Refutations. Routledge.

· Useful anthologies:

Boyd, R., Gasper, P. and Trout, J.D. 1991. The Philosophy of Science. Cambridge, Mass.: MIT Press. [Boyd et al. 1991] at 142(P)

Hacking, I. Scientific Revolutions. Oxford readings in philosophy. Oxford University Press.

Papineau, D. 1996. The Philosophy of Science. Oxford readings in philosophy. Oxford University Press. [Papineau 1996] at 142(P)

Ruben, D-H. 1993. Explanation. Oxford readings in philosophy. Oxford University Press. [Ruben 1993 —a very good collection, but sadly it has already been allowed to go out of print.]

Newton-Smith, W.H. ed. 2000. A Companion to the Philosophy of Science. Oxford: Blackwell. Comprehensive and so somewhat encyclopaedic in treatment, but useful for purposes of reference. [Newton-Smith 2000] at 501 (C)

ASSESSMENT

Two methods of assessment are available for the course, standard assessment and assessment by long essay (mini-dissertation).

1——Standard Assessment

Standard assessment is by a combination of coursework and examination, 50% of the final grade being derived from an end of semester essay and 50% from a two hour examination paper.

Coursework

Deadline: The essay must be submitted by 4pm on Monday of week 12, i.e.:

4pm on Monday 17 December 2001.

For essay titles and further details concerning coursework consult the Coursework Summary.

Examination

Students will be allowed two hours in which to answer two questions.

The questions on the examination paper will be pre-released.

2——Assessment By Long Essay (Undergraduate Dissertation)

Students can also exercise an option to be assessed by dissertation/long essay (in one module per semester for Single Philosophy, and in one module during the year for Dual Honours) . Some topics in the philosophy of science would certainly be suitable for students wishing to take this option. But you should only undertake the dissertation for positive reasons — i.e., because there is a topic you have ideas about and wish to investigate more deeply. Being assessed in this way will almost inevitably involve more work than assessment by a combination of essay + exam. Those intending to submit a long essay must notify the Departmental Office by Monday of week 8 (19 November), by providing an A4 outline signed as having been discussed with and approved by the lecturer (i.e., George Botterill in this case).

Deadline:

The deadline for submission of long essays is

4pm on Tuesday 29 January 2002.

For suggested titles and further details concerning the long essay/dissertation, consult the Coursework Summary.

Advisory Tutorials:

All students should attend an advisory tutorial on coursework, for which they will need to submit an essay plan in advance. Students intending to be assessed by long essay will need two meetings: a short initial meeting before the end of week 7 to obtain approval for their title and plan, and a subsequent meeting to discuss a draft. Submission of drafts by email attachment is a useful and efficient procedure, both for standard assessment and long essays.

CLASSES

I hope it won’t be necessary to distinguish between lectures and seminars. In other words, not only will I pause to take questions but do interrupt me any time you want to! In previous sessions this procedure has worked well. In general, at least a third of the class-time should be spent in discussion.

***** Something to note: Lecturers are asked to write comments on record cards at the end of the semester about attendance and contributions to discussion. These cards are kept in store, largely so we have some information from which to give references in future years, after students have graduated. It is therefore very much in your own interests (e.g., with future career prospects in mind) to enable us to vouch for such qualities as reliability, punctuality, and articulateness.*****

TOPICS AND READING

The following list gives topics for discussion, plus recommended associated reading. We will be going through them in much this order on the course, starting from some general methodological issues about how scientific theories are developed and assessed; looking at a particular seminal, historical period in the development of science (the

Copernican Revolution); then taking up accounts of explanation and laws of nature; a selected topic in social theory; and finally concluding with one or two special topics (prediction v accommodation, thought-experiments).

#1 Inductivism and the Problem of Induction

It’s important to realise that whether inductive reasoning provides the basic method of scientific theory-formation and whether induction can be rationally justified are distinct, albeit interrelated, issues. For it seems that Inductivism is an inadequate methodological view — because it confuses discovery and justification, and cannot do justice to the creativity involved in theorizing — but that we do nonetheless need to rely on some forms of inductive reasoning. Probably the main task in justifying induction is to give a good description of what inductive inferences are to be justified. Many philosophers think of induction as Induction by Simple Enumeration. This has the advantage of being a well-defined formal process, but is definitely too simplistic as an account of our actual inductive practices. See also the sections on Goodman’s Paradox and Inference to the Best Explanation for further attempts to characterise defensible forms of inductive inference.

Further Reading

Russell B .1912 The Problems of Philosophy, 33-8. Reprinted in Swinburne R ed, The Justification of Induction, 19-25. A classic statement.

Chalmers AF What Is This Thing Called Science?, ch 2, 12-19.

Will FL.1947 Will the future be like the past?. Mind LVI, 332-47.

Edwards P.1949 Russell’s doubts about induction. Mind LXVIII, 141-63. Reprinted in Swinburne R ed, The Justification of Induction, 26-47.

Strawson PF. 1952 Introduction to Logical Theory, ch 9.II The "justification" of induction, 248-63.

Ayer AJ Probability and Evidence, ch 1 The legacy of Hume

Popper KR.1963 Conjectures and Refutations, paper 10

Popper KR. 1972 Objective Knowledge, ch 1

Blackburn S Reason and Prediction, ch 1. (against Strawson and Edwards!)

Stove DC. 1986 The Rationality of Induction

#2 Popper’s Falsificationism

According to Popper, a theory is only scientific if it is falsifiable. This is his famous Demarcation Criterion, which is intended to differentiate genuine science from both metaphysics and “pseudo-science”. Popperian falsificationism has several important merits: it accounts for the emphasis on testability in scientific inquiry; it offers a plausible diagnosis of what’s wrong with certain theories; it promises an account of the rational and progressive nature of science; and it spares us many of the problems and intricacies of confirmation theory.

There are, however, several serious objections to Popper’s position. A particularly important one concerns the role of auxiliary hypotheses in scientific theorizing. I shall refer to it as the Duhemian point (although it is more often — and quite inaccurately — called “the Duhem-Quine Thesis”), after Pierre Duhem. Note that this objection seems to have been independently discovered by Lakatos and Putnam.

Further Reading

Popper KR. 1963 Conjectures and Refutations, first paper

Popper KR. 1972 Objective Knowledge, ch 1

Putnam H. 1974 The ‘corroboration’ of theories. In Schilpp PA ed, The Philosophy of Karl Popper Vol I, 221-40. Reprinted in Hacking I ed, Scientific Revolutions, 60-79; and in Putnam H, Mathematics, Matter and Method, 250-69; and in Boyd et al. 1991, 121-37.

Watkins J. Popper. In Newton-Smith 2000, pp.343-8

Duhem P 1906; trans. 1954 The Aim and Structure of Physical Theory, ch VI, 180-90.

Lakatos I 1974 Popper on demarcation and induction. In Schilpp PA ed, The Philosophy of Karl Popper, 241-73. Reprinted in Lakatos I, The Methodology of Scientific Research Programmes, Philosophical Papers Vol 1, 139-67.

#3 Kuhn on Normal and Revolutionary Science

‘Thomas Kuhn invites us to think of scientific progress as exercises in imitation interrupted by changes in fashion.’ (Sylvain Bromberger)

Kuhn himself characterizes the general objective of his work:

‘as an attempt to show that existing theories of rationality are not quite right and that we must readjust or change them to explain why science works as it does. To suppose, instead, that we possess criteria of rationality which are independent of our understanding of the essentials of the scientific process is to open the door to cloud-cuckoo land.’ (Criticism and the Growth of Knowledge, p.264)

Kuhn divides scientific activity into two mutually interdependent but quite distinct categories: normal science and revolutionary science. Normal science is ‘research firmly based upon one or more past scientific achievements’. It consists mainly in ‘puzzle-solving’ within a particular theoretical framework – within a particular paradigm, in Kuhn's terminology. It’s a gradual, somewhat derivative activity, filling in the details, elaborating on themes already conceived. Revolutionary science, by contrast, is a period of discontinuity, one edifice being overthrown and another theoretical structure raised up in its place. What strikes Kuhn's critics as particularly alarming is that he does not think that in scientific revolutions new theories triumph over old because of crucial experiments. On the contrary Kuhn maintains that experiments are only thought of as crucial with hindsight, and moreover if theories were only assessed on hard factual criteria (rather than on such factors as promise and aesthetic appeal) there would be hardly any revolutionary changes in science.

While normal science proceeds through a series of struggles to eliminate anomalies (apparent counterinstances), a revolutionary phase sets in when the weight of anomalies encountered within that particular tradition grows too great for the scientific community to bear. Such a situation makes scientists more receptive to novel theories – in particular, novel theories that can deal with anomalies which a lavish expenditure of scientific ingenuity has failed to reconcile with the old theory. Thus the ability to explain previously anomalous phenomena is regarded as strongly confirming the new theory:

‘Probably the single most prevalent claim advanced by the proponents of a new paradigm is that they can solve the problems that have led the old one to a crisis. When it can legitimately be made, this claim is often the most effective one possible...’ The Structure of Scientific Revolutions, p.153

Further Reading

T.S. Kuhn.1962. The Structure of Scientific Revolutions[especially ch.III The Nature of Normal Science, ch.X Revolutions as Changes of World View, and ch.XII The Resolution of Revolutions]

Rorty R. Kuhn. In Newton-Smith 2000, pp.203-6

K.R. Popper Objective Knowledge, pp.13-21

I. Lakatos & A. Musgrave, eds.1970. Criticism and the Growth of Knowledge [most of the papers are relevant, but particularly J.W.N. Watkins: ‘Against normal science’, pp.25-37; K.R. Popper: ‘Normal science and its dangers’, pp.51-8; and T.S. Kuhn on ‘Irrationality and theory-choice’, pp.259-66 — in which Kuhn denies that he is an irrationalist.]

A.F. Chalmers What Is This Thing Called Science? ch.8

#4 The Copernican Revolution

We take the history of astronomy as our case-study (to see whether it fits any of the methodological moulds provided by Popper, Kuhn, and Lakatos) because it is a widely accessible subject, because the Copernican revolution was of such great historical significance in the development of modern science, and because it is a well studied area in the history of science, frequently cited in philosophical debates. A little study of the history of planetary astronomy should also disabuse us of several popular misconceptions. Thus, Greek astronomers realised as early as the 5th century BC that the earth was spherical, not flat — why else would Eratosthenes go on to calculate its circumference? The device of the epicycle, as used by Ptolemy, was not such a horribly ad hoc and overcomplicated resource — and, besides, Copernicus used epicycles too. It is of particular interest that heliocentrism — the ‘Copernican theory’ that the planets revolve around the sun — had already been proposed by Aristarchus of Samos. As Ptolemy (c.150AD) explains in The Almagest, however, it was regarded as refuted by empirical observation, viz. 1) the absence of any observed stellar parallax, and 2) none of the effects in the terrestrial environment that might be supposed to result from the earth’s rotation.

Further Reading

Kuhn TS. 1957 The Copernican Revolution, chs 5-6

Dreyer JLE [1906/1953] A History of Astronomy from Thales to Kepler, chs XIII-XV

Koestler A The Sleepwalkers, Pt I & Pt III

Feyerabend PK. 1975 Against Method, chs 6-11

Lakatos I & Zahar EG. 1976 Why did Copernicus’s programme supersede Ptolemy’s?. In Westman R ed, The Copernican Achievement, 354-83. Reprinted in Lakatos I, The Methodology of Scientific Research Programmes, Philosophical Papers Vol 1, 168-92.

**** Library Guide to further reading: Solar system astronomy is shelved at 520 in the Main Library; history of astronomy is at 520.9; and works on Copernicus and Galileo in particular are at 520.92. ****

#5 Lakatos’ Methodology of Research Programmes

Lakatos’s MRP, although originally proposed as a sophisticated version of Popperian falsificationism, looks to be a synthesis that combines what ought to be retained in the views of Popper and Kuhn. Lakatos proposes that research programmes are to be appraised over a period of time, according to whether they are progressive or degenerative. He thus avoids the relativism of Kuhn, while allowing a theory to prove its mettle by introducing modifications in the ‘protective belt’ of auxiliary hypotheses.

“Neither the logician’s proof of inconsistency nor the experimental scientist’s verdict of anomaly can defeat a research programme in one blow. One can be ‘wise’ only after the event.” [Lakatos, 1971]

The main point — against ‘naive falsificationism’ (Popper) — is that theories of a certain sort (of a mature science / in the ‘hard core’ / of a high level of theoreticity / framework theories) are not sharply falsifiable. They can be cumulatively disconfirmed by exhibiting ‘degenerating problem-shift’, but they can’t be decisively refuted or knocked out by a single crucial experiment. This has further consequences — notably, that Popper’s Demarcation Criterion cannot be upheld. Lakatos went on to suggest (see ‘History of science and its rational reconstructions’ in the Howson volume) that methodologies can be checked out by the degree to which they accord with the history of science.

One can only be wise after the event. But when is that? Feyerabend (1971) objected that Lakatos’ criteria for rational theory change in science were bogus because it was not possible to specify any particular time at which assessment for progress or degeneration of a research programme should be carried out. A theory had to be given a chance ‘to prove its mettle’. But it is always possible that a previously degenerating research programme might be on the brink – after the next modification of auxiliaries – of a period of glorious progress.

Further Reading

Kuhn TS. 1962 The Structure of Scientific Revolutions, ch XII The Resolution of Revolutions.

Lakatos I. 1970 Falsification and the methodology of scientific research programmes. In Lakatos I & Musgrave A eds, Criticism and the Growth of Knowledge. Reprinted in Lakatos I, Philosophical Papers Vol 1.

Lakatos I. 1971 History of science and its rational reconstructions. In Howson C ed, Method and Appraisal in the Physical Sciences. Also in Hacking I ed, Scientific Revolutions; Lakatos I, Philosophical Papers Vol 1.

Feyerabend PK. 1971 On the critique of scientific reason. In Howson C ed, Method and Appraisal in the Physical Sciences. Reprinted in Feyerabend PK, Philosophical Papers Vol II Problems of Empiricism, under the title ‘The methodology of scientific research programmes’.

Hacking I. 1979 Imre Lakatos’s philosophy of science. British Journal for the Philosophy of Science XXX, 381-410. Revised extracts reprinted in Hacking I ed, Scientific Revolutions, 128-43.

Larvor, B. 1998 Lakatos: an introduction. Routledge.

Nickles, T. Lakatos. In Newton-Smith 2000, pp.207-12.

#6 Feyerabend the Anarchist

After the great triumvirate of Popper, Kuhn and Lakatos, a very special place in 20th century philosophy of science is occupied by Paul Feyerabend. His distinctive and provocative views (the Incommensurability Thesis of the 60s and 70s, the Methodological Anarchism of the 80s) have been vigorously attacked and almost universally rejected. But haven’t we been enriched by the process?

Further Reading

Preston JM 1997. Feyerabend: Philosophy, Science and Society. Cmbridge: Polity Press.

Preston JM. Feyerabend. In Newton-Smith 2000, pp.143-8.

On Incommensurability —Feyerabend PK 1965 On the ‘meaning’ of scientific terms. Journal of Philosophy LXII, 266-74. Reprinted in his Philosophical Papers Vol I, Realism, Rationality & Scientific Method.

Feyerabend PK 1970 Consolations for the specialist. In Lakatos I & Musgrave A eds, Criticism and the Growth of Knowledge. Reprinted in his Philosophical Papers Vol II, Problems of Empiricism.

Shapere D Meaning and scientific change. In Colodny RG ed, Mind & Cosmos, 44-85. Abridged version reprinted in Hacking I ed, Scientific Revolutions.

Achinstein P 1968 Concepts of Science, ch 3

Kordig CR 1971 The Justification of Scientific Change, ch 3

Newton-Smith WH The Rationality of Science, ch VII

On Anarchism —

Stove DC 1982 Popper and After

Feyerabend PK1975 Against Method, passim, but especially chs 6-11

Chalmers A 1985 Galileo’s telescopic observations of Venus and Mars. British Journal for the Philosophy of Science 36, 175-84

#7 Explanation

Explanations are obviously a highly diverse bunch, differing in many ways. But is it nonetheless possible to give an analysis of what makes an explanation explanatory? It is quite a natural philosophical ambition to try to set out what all genuine explanations have in common with each other. A terminological start can be made by separating the explanandum (Latin for that which is to be explained) from the explanans (Latin for what does the explaining). That bit of jargon may save a few words; and we can further safely say that the explanans must supply some information. But then it gets difficult. Just what are the conditions that information must satisfy, in relation to a given explanandum, in order to constitute an explanation?

The Deductive-Nomological (or Covering Law) Model claims that adequate scientific explanations involve subsuming what is to be explained (the explanandum) under a general law, by displaying it as a deductively entailed consequence of statements of laws and initial conditions (the explanans). So on this view an explanation has the form of an argument, with the explanans as the premises and the explanandum as the conclusion – which makes giving an explanation much like deriving a prediction, only with hindsight. This is frequently cited, outside philosophy of science, as the conventional or orthodox view of scientific explanation. But, as you will see, within the philosophy of science the D-N Model has had few supporters since its great advocate, Carl Hempel. See, for example, Achinstein 1969 and Brody 1972 for severe objections.

One diagnosis of where the D-N Model goes wrong is that it fails to require that the information supplied in the explanans should be about causes of the phenomenon to be explained. That in turn suggests that theories of causal explanation should be explored – e.g., Woodward 1984, Lewis 1986.

An important point to note is that requests for explanation are often formulated in terms of a contrast — Why P rather than Q? So there has been considerable interest over the past decade or so in contrastive explanation (which can be seen as a kind of causal explanation — see Lipton 1990).

Another point that should not be forgotten is that explaining is something that we do. Indeed, it is a kind of speech act. Without us in the world, there would be no shortage of causation. But absent humans and other intelligent life-forms, no explaining would go on. If we take this point seriously then we should heed the importance of context. It’s tempting to suggest that what is the right (or best) explanation depends, at least to some extent, upon context. Would you offer the same explanation to a young child? To an intelligent layman? To an expert in the field?

Further Reading

Newton-Smith WH. Explanation. In Newton-Smith 2000, pp.127-33.

Achinstein P 1969 Law and Explanation, ch V, pp.99-109

Achinstein P 1981 Can there be a model of explanation?. Theory and Decision 13, 201-27. Reprinted in Ruben 1993.

Brody B 1972 Towards an Aristotelian theory of scientific explanation. Philosophy of Science 39, 20-31. Reprinted in Ruben 1993.

Coffa JA 1974 Hempel’s ambiguity. Synthese 28. Reprinted in Ruben 1993.

Gasper P 1990 Explanation and scientific realism. In D. Knowles ed, Explanation and its Limits, 285-95

Harré HR The Philosophies of Science, p.56, p.61, and pp.168-83

Harré HR The Principles of Scientific Thinking, ch 1, pp.15-21

Hempel CG Explanation in science and in history. In R.G.Colodny ed, Frontiers of Science and Philosophy, 7-33. Reprinted in P.H.Nidditch ed, The Philosophy of Science, 54-79; and in Ruben 1993.

Hempel CG & Oppenheim P 1948 Studies in the logic of explanation. Philosophy of Science 15, 135-78

Hempel CG 1965 Aspects of Scientific Explanation, 245-95. Extract reprinted in Ruben 1993.

Hempel CG 1966 Philosophy of Natural Science, ch 5. Reprinted in Boyd et al. 1991.

Kim J 1987 Explanatory realism, causal realism, and explanatory exclusion. Midwest Studies in Philosophy 12, 225-39. In Ruben 1993.

Kinoshita J 1990 How do scientific explanations explain?. In D. Knowles ed, Explanation and its Limits, 297-311

Kitcher P 1981 Explanatory unification. Philosophy of Science 48, 507-31. Reprinted in Boyd et al. 1991.

Lewis D 1986 Causal explanation. In his Philosophical Papers, 214-40. Reprinted in Ruben 1993.

Lipton P 1990 Contrastive explanation. In D. Knowles ed, Explanation and its Limits. Reprinted in Ruben 1993.

Matthews RJ 1981 Explaining and explanation. American Philosophical Quarterly 18, 71-7. In Ruben 1993.

Nagel E 1961 The Structure of Science, chs 2 and 3

Ryan AR The Philosophy of the Social Sciences, ch 3

Scriven M 1962 Explanation, prediction and laws. Minnesota Studies in the Philosophy of Science Vol.III, 170-230

Taylor DM Explanation and Meaning, ch 2

van Fraassen B 1977 The pragmatics of explanation. American Philosophical Quarterly 14,143-50. Reprinted in Boyd et al. 1991.

Woodward J 1984. A theory of singular causal explanation. Erkenntnis 21. In Ruben 1993.

— Also: An electronic version of the paper ‘Difference, explanation and causal history’ by George Botterill and Mark Day (presented to the 2000 Hang Seng Conference on The Roots of Scientific Reasoning and currently subject to pre-publication refereeing) is available on request.

#8 Functional Explanation

This is in itself a large topic, for which the entry-level problems are:

1 The Problem of Causal Order: functions are effects, so doesn’t functional explanation invert the ordinary causal order?

2 The Normative Problem: a thing’s function is what it ought to do, but isn’t this worryingly evaluative?

A standard selectionist/adaptationist account appears to solves these two:

The function of C is F (where C is some anatomical feature or behavioural pattern) because

1. Under normal environmental conditions the presence of C in an organism tends to result in F.

2. F is adaptively valuable, i.e. it increases an organism's chances of survival and reproduction.

3. Therefore, lack of C is an adaptive disadvantage.

4. Therefore, organisms that lack C will be eliminated (will not be able to survive or reproduce in competition with organisms that possess C).

So, functional explanations in evolutionary biology work through the mechanism of elimination.

the problem of causal order resolved: what the functional explanation explains is the diffusion and continued presence of the functional ‘element', not its initial appearance (a lucky genetic accident). In other words, functional explanations in evolutionary biology explain why something sticks and spreads; they do not explain its causal origin.

the normative problem resolved: the process of selection simulates design, because only those organisms that are in fact well-adapted will be able to survive and reproduce.

Further Reading

Ayala, FJ.1970. Teleological explanation in evolutionary biology. Philosophy of Science 37

Beckner, M.1969. Function and teleology. Journal of the History of Biology 2. Reprinted in M. Grene & E. Mendelsohn eds [1976], Topics in the Philosophy of Biology, 197-212.

Bigelow, J & Pargetter, R. 1987. Functions. Journal of Philosophy 84. pp.181-96

Boorse, C.1976. Wright on functions. Philosophical Review, pp.70-86

Canfield, J. 1964. Teleological explanations in biology. BJPS 14

Cummins, R The Philosophy of Biology (MIT Press)

Cummins, R.1975. Functional analysis. Journal of Philosophy 72, pp.741-65

Darden, C. & Cain, J.A. 1989. Selection type theories. Philosophy of Science 56, pp.106-29

Griffiths, P.E. 1993. Functional analysis and proper functions. British Journal for the Philosophy of Science 44, pp.409-22

Kernohan, A. 1987. ‘Teleology and logical form', BJPS 38, 27-34

Lehman, H. 1965. Functional explanations in biology. Philosophy of Science 32

Millikan, RG.1989. In defence of proper functions. Philosophy of Science 56, 288-302

Millikan, RG. 1990. Truth rules, hoverflies, and the Kripke-Wittgenstein paradox. Philosophical Review XCIX, 323-53

Nagel, E.1977. Teleology revisited. Journal of Philosophy 84, pp.261-301

Neander, K.1988. What does natural selection explain? Correction to Sober. Philosophy of Science 55, pp.422-6

Neander, K. 1991a. The teleological notion of "function". Australasian Journal of Philosophy 69, pp.454-68

Neander, K. 1991b. Functions as selected effects: the conceptual analyst’s defence. Philosophy of Science 58, pp.168-84

Ruse, M. 1971. Function statements in biology. Philosophy of Science 38

Wright, L. 1973. Functions. Philosophical Review 82, 139-98. Reprinted in M. Grene & E. Mendelsohn eds [1976], Topics in the Philosophy of Biology, 213-42.

#9 Two Famous Paradoxes

— Goodman’s Grue

Let something be grue iff

for any time t<T, it is green, or

for any time t>T, it is blue.

Informally, we may say an object is grue just in case it’s green up to some specified time T or blue thereafter, if still in existence.

The paradox is supposed to be generated by the following considerations, taking T to be some time in the future:

everything that we have observed to be green we have also observed to be grue

so every pre-T observation that is a positive instance of ‘All emeralds are green’ is also a positive instance of ‘All emeralds are grue’

BUT ‘All emeralds are green’ and ‘All emeralds are grue’ are different hypotheses which yield mutually inconsistent predictions about the colour of emeralds after T

We could make T any time we like (8 am tomorrow, the beginning of next week, the start of the 21st century, etc.). Does this mean that previous observations of emeralds – every one of them green – provide just as good evidence for thinking that future emeralds will be blue as for thinking they will be green?

Projectively paradoxical predicate pairs

A pair of predicates, F and G, will produce paradoxical projections if the following conditions are met:

#1 Past (pre-T) observations that something is F are also observations that it is G

#2 Future projection of the predicates F and G yield inconsistent predictions

#3 F and G are symmetrical with respect to confirmation: i.e., observed members of some kind K having been found to be G is just as good a reason for thinking that other members of kind K are G as is the fact that observed members of kind K have been found to be F is for thinking that other members of kind K are F

In attempting to resolve Goodman’s Paradox it’s #3 that looks the most promising requirement to question. Is the fact that previously observed emeralds have been grue any reason at all to think that ‘All emeralds are grue’? If not, why not? Can a scientific realist dissolve the paradox by saying that positive instances do not confirm in the absence of some underlying theoretical process or generating mechanism?

Further Reading

Trout, JD. Confirmation, Paradoxes of. In Newton-Smith 2000, pp.53-5.

Goodman, N. 1955. Fact, Fiction and Forecast, ch 3

Barker, S & Achinstein, P. 1960 On the new riddle of induction. Philosophical Review LXIX, 511-22. See also the reply ‘Positionality and pictures’ that follows by Goodman,

pp.523-5. Both are reprinted in Nidditch PH ed, The Philosophy of Science, 149-61 and 162-4.

Thompson, JJ. 1966. Grue. Journal of Philosophy LXIII, 289

Fain, H. 1967. The very thought of grue. Philosophical Review LXXVI, 61-73.

Hooker, CA. 1968. Goodman, ‘grue’, and Hempel. Philosophy of Science 35, 232-47.

Blackburn, S. Goodman’s paradox. In Studies in the Philosophy of Science, American Philosophical Quarterly monograph series, 128-42.

Blackburn, S. Reason and Prediction, ch 4

Hesse, MB. 1969. Ramifications of grue. British Journal for the Philosophy of Science XX, 13-25.

Hesse, MB. The Structure of Scientific Inference, ch 3

— Hempel’s Ravens

The paradox is generated by the following propositions, each of which seems quite plausible in itself:

1) Observations of black ravens confirm ‘All ravens are black’ (and, more generally, positive instances confirm).

2) Observations of non-ravens are neutral with respect to the confirmation of ‘All ravens are black’.

3) If observations confirm one formulation of a hypothesis, then they confirm any logically equivalent formulation.

[3) is known as the Hypothesis Equivalence Condition, one version of which is: If h and h* are logically equivalent, and e confirms h*, then C(h/e) = C(h*/e).]

BUT :

(a) ‘All ravens are black’ is logically equivalent to

(b) ‘All non-black things are non-ravens’; and also to

(c) ‘Anything whatsoever, whether a raven or not, is either black or a non-raven’.

Positive instances of (a) are black ravens; positive instances of (b) include such items as white handkerchiefs, green leaves, red post-boxes, etc. (anything that satisfies both antecedent and consequent, i.e. anything that is both non-black and not a raven); and positive instances of (c) are anything at all except for non-black ravens (note that (c) has more positive instances than (b) — e.g., such items as black shoes, black swans, etc.).

Now, by 1) and 3), positive instances of (b) and (c) should also confirm ‘All ravens are black’. But by 2) they should be neutral with respect to the confirmation of ‘All ravens are black’. This constitutes the paradox.

#10 LAWS OF NATURE (and universally quantified conditionals)

It’s important to remember that one may be referring to two different sorts of things when speaking of ‘laws’. One may be talking about law-statements or about whatever it is in nature that makes such statements true, when they are true. Laws are things that we discover. (This may be a realist prejudice, but it does at least need to be argued against by someone who takes a subjectivist or epistemological view of laws.)

Philosophers of science, particularly logical positivists, had been tempted to suppose that law-statements were statements of the logical form: (x) (Fx ® Gx). However, it’s quite obvious that there are many true statements of the form (x) (Fx ® Gx) which are not laws. So it was concluded that there is a distinction to be drawn between accidentally true generalizations and nomic (law-like) generalizations. Perhaps laws where what was expressed by (x) (Fx ® Gx) generalizations which also satisfied some further condition (such as having purely qualitative predicates, not being spatio-temporally restricted, supporting counterfactuals). But it was really difficult to specify that extra condition!

There are, in any case, several major problems with the idea that law-statements have the form (x) (Fx ® Gx). E.g.: (1) Laws are referentially opaque, not transparent; (2) (x) (Fx ® Gx) can be vacuously true; (3) Arguably, laws can be confirmed in ways that (x) (Fx ® Gx) statements cannot.

But perhaps the major issue dividing realists and positivists about laws is this: is a sufficiently widespread regularity a law? Or can there be laws without regularities and regularities without laws? Consider the following test: Can two possible worlds differ in their laws, without differing in actual regularities? Yes = you’re a realist! No = you’re a positivist! We’ll be considering Tooley’s thought-experiment in favour of a realist answer.

Further Reading

Nagel, E. 1961. The Structure of Science, ch 4

Ayer, AJ. What is a law of nature?. In his The Concept of a Person.

Harré, HR.1970. The Principles of Scientific Thinking, ch 4

Achinstein, P. Law and Explanation, chs 1-3; but esp. ch 3.

Dretske, F.1977. Laws of nature. Philosophy of Science 44, 248-68.

Tooley, M. 1977. The nature of laws. Canadian Journal of Philosophy 7, 667-98.

Armstrong, DM. 1983 What is a Law of Nature?, Cambridge UP

Urbach, P. 1988 What is a law of nature? A Humean answer. British Journal for the Philosophy of Science XXXIX, 193-210.

Harré, HR. Laws of Nature. In Newton-Smith 2000, pp.213-23.

Drewery, A. 2000. Laws, regularities and exceptions. Ratio, pp.1-9.

#11 Realism — For and Against

Realism about scientific theories seemed to be firmly established after the rejection of positivism that started in the 1960s. Theories actually do postulate previously unobserved forces and entities and do attempt to describe the structure of the universe and its contents. (Though van Fraassen stubbornly holds out against this view, arguing that since in the end we could never discriminate between theories that are empirically adequate and theories that are actually true, we have no reason to aim for the latter rather than the former; see van Fraassen 1976, 1980, for his ‘constructive empiricism’. Seems like positivism to me — and wrong for much the same reasons!) Ian Hacking (Hacking 1982, 1983) has been influential, arguing that experimental manipulation and intervention commit us to realism more deeply than theory alone can. As he memorably put it, ‘If you can spray them, they exist!’.

But there are two aspects to realism in science, which we can label realism of intent and realism of fact (see Botterill & Carruthers, 1999. The Philosophy of

Psychology, ch.2). So, we are trying to describe causal mechanisms, micro-structures, and lawful connections between properties (realism of intent). But the realist surely wants to go further and say that science has been largely successful in this enterprise (realism of fact) — that the world actually is the way scientific theories tell us it is.

Here two notorious arguments have been advanced, pointing in oppositie directions:

· According to the No Miracles Argument, scientific theories make so many successful predictions and work so well in technological application that we ought to believe they are true, at least in the main. For it would just be miraculous, if they were false and so successful. The best explanation for their success is that they are (approximately, at any rate) true.

· The contrary case is urged by the Pessimistic Meta-Induction (see Laudan 1981): most successful theories in the past have ultimately come to be rejected as false. Why should our theories be any different? The lesson that the history of science teaches (the meta-induction) is that, however successful they may be at any one time, scientific theories are probably false.

Further Reading

Boyd, R. 1983 On the current status of scientific realism. Erkenntnis 19, 45-90. Reprinted in Boyd et al. 1991.

Boyd, R. 1990 Realism, approximate truth, and philosophical method. In C.W. Savage, Scientific Theories, Minnesota Studies in the Philosophy of Science 14, 355-91. Reprinted in Papineau 1996.

Fine, A. 1984 The natural ontological attitude. In J. Leplin ed, Scientific Realism, Univ. of California Press, 83-107. Reprinted in Boyd et al. 1991; and in Papineau 1996.

Hacking, I. 1982 Experimentation and scientific realism. Philosophical Topics 13, 71-87. Reprinted in Boyd et al. 1991.

Hacking, I. 1983 Representing and Intervening. Cambridge University Press.

Laudan, L. 1981 A confutation of convergent realism. Philosophy of Science 48, 19-48. Reprinted in Boyd et al. 1991; and in Papineau 1996.

Laudan, L. 1987. Progress or rationality? The prospects for normative naturalism. American Philosophical Quarterly 24, 19-31.

Lipton, P. 1993 Is the best good enough?. Proceedings of the Aristotelian Society XCIII, 89-104. Reprinted in Papineau 1996.

Quine, W. 1969 Natural kinds. In his Ontological Relativity and Other Essays, 114-38. Reprinted in Boyd et al. 1991.

van Fraassen, B. 1976 To save the phenomena. Journal of Philosophy LXXIII, 623-32. Reprinted in Boyd et al. 1991; and in Papineau 1996.

van Fraassen, B. 1980 The Scientific Image. Oxford University Press.

Worrall, J. 1989 Structural realism: the best of both worlds?. Dialectica 43, 99-124. Reprinted in Papineau 1996.

Leplin J. Realism and Instrumentalism. In Newton-Smith 2000, pp.393-401.

[Note: Almost all the papers in Papineau 1996 are on this topic.]

#12 Popper Against Historicism

Popper advanced a whole battery of arguments against the idea that the aim of social theory was to discover laws of historical change that would enable future social developments to be predicted, viz. (all quotations from The Poverty of Historicism):

1 The Unique Process Argument: “The most careful observation of one developing caterpillar will not help us to predict its transformation into a butterfly.”

2 The Multiplicity of Laws Argument: “... no sequence of, say, three or more causally connected concrete events proceeds according to any single law of nature.”

3 The Laws v Trends Argument: “This, we may say, is the central mistake of historicism. Its ‘laws of development’ turn out to be absolute trends...”

4 The Prophecy v Prediction Argument: “They are the basis of unconditional prophecies, as opposed to conditional scientific predictions.”

There is no doubt that the main target Popper had in mind was Marxism. But the arguments are interesting in their own right — not least because in some respects they are difficult to reconcile with Popper’s own falsificationism!

Further Reading

Popper K.R. The Poverty of Historicism, especially section IV.

Popper K.R. Prediction and prophecy in the social sciences; paper 16 in his Conjectures and Refutations.

Addis, L. 1968.Historicism and historical laws of development. Inquiry 11, 155-74.

Shaw P.D. 1971. Popper, historicism and the remaking of society. Philosophy of the Social Sciences 1, pp. 299-308.

Suchting, W.A. Marx, Popper and ‘Historicism’. Inquiry 15 [1972], pp.235-66.

Donagan A. Popper’s examination of historicism. In P.A. Schilpp ed, The Philosophy of Karl Popper, pp. 905-24.

Urbach P. Is any of Popper’s arguments against historicism valid?. British Journal for the Philosophy of Science 29 [1978], pp. 117-30.

Olding A. A defence of evolutionary laws. British Journal for the Philosophy of Science 29 [1978], pp. 131-43.

#13 Observation

Positivist philosophy of science (e.g. up to E. Nagel’s The Structure of Science, 1961) supposed that there was a given level of observation, which had a special epistemic status. Reports of observations were the sorts of thing we could directly know to be true. (This is a form of Epistemological Foundationalism.) This corresponded to a dichotomy between the observable and the unobservable. The problem for the positivists was how statements about unobservable theoretical entities could be meaningful. This they attempted to explain by means of upward seepage of meaning (the so-called ‘partial interpretation' account of theoretical significance).

But from the early 1960s a number of philosophers of science – notably Kuhn (‘Revolutions as Changes of World-View’), Feyerabend (‘Consolations for the Specialist’), and N.R. Hanson (Patterns of Discovery) – argued very vigorously that all observation is theory-laden.

Further Reading

Chalmers, AF. What Is This Thing Called Science?, ch 3

Newton-Smith, WH. The Rationality of Science, ch II

Kuhn, TS. 1962 The Structure of Scientific Revolutions, ch X Revolutions as changes of world-view.

Maxwell, G. 1962 The ontological status of theoretical entities. Minnesota Studies in the Philosophy of Science Vol 3, 3-27.

Achinstein, P. 1965. The problem of theoretical terms. American Philosophical Quarterly 2, 193-203.

Achinstein, P. 1969 Concepts of Science, ch 6, 179-201.

Hanson, NR. Patterns of Discovery, ch 1 (also 2 & 3).

Ryle, G. Dilemmas, ch VI, 82-92.

Churchland, PM. Scientific Realism and the Plasticity of Mind, chs 1 & 2.

Spector, M. 1966. Theory and observation. British Journal for the Philosophy of Science 17, part I 1-20, part II 89-104.

Kordig, CR. 1971. The theory-ladenness of observation. Review of Metaphysics 24.

Shimony, A. 1977. Is observation theory-laden? A problem in naturalistic epistemology. In Colodny RG ed, Logic, Laws & Life, 185-208.

Shapere, D. 1982. The concept of observation in science and philosophy. Philosophy of Science XLIX, 485-525.

Fodor, J. 1984. Observation reconsidered. Philosophy of Science LI, 23-43.

Torretti, R. 1986 Observation. British Journal for the Philosophy of Science 37, 1-23.

Bogen, J. & Woodward, J.1988 Saving the phenomena. Philosophical Review XCVII, 303-52.

Churchland,PM.1988. Perceptual plasticity and theoretical neutrality: a reply to Jerry Fodor. Philosophy of Science 55, 167-87.

Fodor, J. 1991. The dogma that didn’t bark. Mind C, 201-20.

Achinstein, P. Observation and Theory. In Newton-Smith 2000, pp.325-34.

#14 Inference to the Best Explanation

The view that we reason inductively from the phenomena by means of inference to the best explanation is currently rather popular. But what does inference to the best explanation involve? Is there really any such single distinctive process of reasoning? Presumably we will prefer better explanations to ones that are less good. But are there any general grounds for such preferences that are not already dependent upon evidential support?

We will also be considering the main claims of a Bayesian approach to the confirmation of theories. Bayesianism insists that we should view the degree of confirmation of a theory as a subjective probability which is to be updated in accordance with the axioms of the probability calculus. Part of this approach is uncontentious: if we are to assign probabilities to hypotheses, then surely we should do so in a way that is consistent with axioms of mathematical probability. But there is a question over whether Bayesianism is really in help in assessing genuine scientific theories — one reason for this being that one may doubt whether, in the case of genuine theories, the relevant probabilities are suitably quantifiable.

Further Reading

Peter Lipton Inference to the Best Explanation, Routledge: 1991, esp. chs. 4-5

Harman, G. 1965. The inference to the best explanation. Philosophical Review 74, pp.88-95.

Howson, C. & Urbach, P. 1989. Scientific Reasoning: the Bayesian approach. Open Court: La Salle, Illinois.

Lipton P. Inference to the Best Explanation. In Newton-Smith 2000, pp.184-93.

#15 Accommodation And Prediction

Does ‘prediction’ [the derivation from a theory of previously unknown results] provide stronger evidence in favour of a theory than ‘accommodation’ [fitting known results in the process of theory-construction]?

Suggestive example: Mendeleyev’s Periodic Table

The fact that Mendeleyev included the 60 then known elements did not impress fellow scientists nearly so much as his prediction of two previously unknown elements. Lipton, p.134: ‘Sixty accommodations paled next to two predictions.’ So, is there a general advantage of prediction over accommodation? And, if so, why?

Further Reading

Peter Lipton Inference to the Best Explanation, ch.8

Paul Horwich 1982. Probability and Evidence, Cambridge UP, pp.108-17

#16 Thought-Experiments

To anyone with empiricist sympathies the operation of learning something just by thinking about a possible situation ought to seem like a bit of cognitive magic. In carrying out any experiment we want to know what the results are. But in order to get any genuine results, surely we have actually to perform an experiment. Just imagining a situation, and then imagining a result — how could that be good for anything?

Further Reading

T.S. Kuhn A function for thought-experiments. In his The Essential Tension, University of Chicago Press: 1977, pp.240-65

J.R. Brown The Laboratory of the Mind, Routledge: 1991

R.A. Sorensen Thought Experiments, Oxford University Press: 1992

George Botterill

The University of Sheffield,

Autumn Semester, 2001 --

Interesante resumen de Lakatos MRP-SRP: http://www.philosophy.ed.ac.uk/ug_study/ug_phil_sci1h/phil_sci_files/L9_SRP.ppt

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interes

http://www.angelfire.com/mn2/tisthammerw/science.html

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http://www.usfca.edu/philosophy/pdf%20files/Abstract%20Popper%20and%20Lakatos.pdf

Friday, June 25 PM 1:30-4:30, Room 140

Session 2 (room 140): Popper and LakatosStefania Jha, “Popper transcended – the Lakatos – Polanyi connection”Stefano Gattei, “Karl Popper’s Philosophical Breakthrough”William M. Shields: Popper's Quantum GhostYuann, Jeu-Jenq, “Lakatos, A Methodologist of Research Programmes or APhilosopher of Political Practices?”----------“Popper transcended – the Lakatos – Polanyi connection”Stefania JhaPopper opposed Lakatos’s several attempts to improve his doctrines instead of promoting Popperism. Lakatos saw that Popper’s formulation of the logic of scientific discovery and the logic of research, although had the merit of simplicity, was not based on fact. No significant scientific discovery in history was made by Popper’s method.The Popper, Lakatos and Polanyi archives give insight into Lakatos’s relationship with Popper and into his theoretical growth – from ‘loyal pupil’ to excommunicated heretic. Popper excommunicated him for criticism, independence and seeing merit in the theories of Popper’s ‘enemies’, Polanyi, Kuhn, and other excommunicated pupils.Lakatos’s analytical mind saw at an early stage, that Popper’s conjectures and refutations formula and his notion of demarcation needed major revision in the general direction Polanyi has pointed out. After Popper’s retirement from the London School of Economics, Lakatos invited Polanyi to give the paper “Genius in Science” summarizing his philosophy of science.Polanyi holds that scientists do not set out to refute their first guesses for an explanation of a phenomenon. Hypotheses are not abandoned at the first disconfirming test. Scientists are not mainly interested in demarcating ‘metaphysics’ from ‘science,’ rather, in distinguishing between good science and bad. This line is drawn by the community of practice. All scientific understanding has metaphysical and psychological underpinnings, even if undeclared. Personal judgment is involved in recognizing a coherence in nature, a good problem, in choosing the best process to investigate a particular problem (heuristics), and in sensing the implications of a solution. Rationality in science is not formal deductive logic, in spite of Popper’s method of testing conjectures.Lakatos recognized that Popper’s campaign against inductivism not-withstanding, something other than deductive logic is used in scientific work. Polanyi’s ‘personal knowledge philosophy’ offered a rather complex structure which included a version of Peirce’s notion of retroduction.In his last papers, Lakatos not only noted that inductivism plays a part in the scientific game, that theories are not rejected at the first negative result but often are adjusted by auxiliary hypotheses, and that judgment in choice of methodologies is a combination of methodological appraisal and heuristic advice.As he noted in one of his letters to Polanyi, Popperites have much to learn from Polanyi (a practicing scientists capable of analyzing his own scientific thinking and activities).Although Lakatos is often thought of as basically a follower of Popper who adapted his former Hegelian-Marxist intellectual framework to Popper’s philosophy, this interpretation seems to me deterministic. It is more likely, that his preoccupation was with methods of thinking (heuristics), as would be indicated by his use of Polya’s explorations in his dissertation (later reworked into Proofs and Refutations), by his correspondence with Kuhn, Feyerabend and his readings of Polanyi on this topic.

His 1973 lectures given at the London School of Economics would indicate he gained his independence from Popper and opened up his investigations further by taking Polanyi’s philosophy into consideration.(stefania1@jha.net)----------“Karl Popper’s Philosophical Breakthrough”Stefano GatteiKarl Popper’s critical rationalism is well-known for its strict deductivism: as the author of The Logic of Scientific Discovery and of many later works clearly states, not only science does not proceed by inductive inferences, but also there simply is no such logical entity as an inductive inference.However, the young Popper thought quite differently. Indeed, if we read his early (unpublished) writings, and particularly Popper’s 1927 thesis, “Gewonheit” und “Gesetzerlebnis” in der Erziehung, we see that he clearly held an inductivist position. Contrary to Freud’s, Adler’s and others’ psychological theories, which often go beyond what is factually verifiable and impose on empirical facts, he argued, natural science theories only abstract from empirical data, never asserting something beyond the facts.In his later reconstructions of the development of his own thought, Popper seemed determined to remove any traces of this early inductivism. However, contrary to what he later urged us to believe, he did not arrive at his criticism of induction in the years between 1926 and 1928, nor did he formulate his famous criterion of demarcation. Moreover, instead of being involved in abstract epistemological and methodological problems, in those years Popper was actually attempting to find his way in the different fields of psychology. Viewing science as an adventurous revolutionary project, an “uneneded quest” for ever growing but never certain knowledge, Popper undertook an autobiography in which a sort of rationality of scientific revolutions dominates the narrative, concealing the plurality of directions in which his thought developed, the diverse options, the intellectual impasses, and the decisive turning points.However, I think we do not have to look for a sort of continuity between Popper’s early writings and his published works. Instead, I think we should look for a break and inquire the reasons for that break. Such a break, I suggest, dates to his third thesis, Axiome, Definitionen und Postulate der Geometrie, completed in 1929: up to this year epistemology entered Popper’s reflections as far as the problem is that of the justification of the scientific character of these fields of research. But in 1929 Popper explicitlydiscussed the cognitive status of geometry without referring to psycho-pedagogical aspects, thus turning from cognitive psychology to the logic and methodology of science. Applied geometry sets the context for Popper’s discussion of scientific rationality. In the following years, he will be applying the hypothetico-deductive model to all natural sciences.(stefano.gattei@tiscali.it)----------Popper's Quantum Ghost“William M. Shields”-insert abstract here—----------“Lakatos, A Methodologist of Research Programmes or a Philosopher of Political Practices?”Yuann, Jeu-Jenq

In the field of philosophy of science, I. Lakatos is first of all considered a philosopher of scientific research programmes. Resent researches demonstrate that an essential part of what Lakatos has achieved in his LSE period reflects the influences he received before settling in England. These researches have their origin consisting in I. Hacking’s paper on Lakatos’ philosophy of science. According to Hacking, Lakatos’ papers published during the period of LSE time would not constitute a coherent picture unless the Hungarian conception of the events of modern philosophy is incorporated into the attempt of a complete understanding of Lakatos. The ‘incoherence’ refers to the fact that the methodology of scientific research programmes as a ‘synthesis’ of Popper and Kuhn’s philosophy of science is insufficient to vindicate the image that science is an enterprise of objective rationality and of constant growth. While Lakatos expresses explicitly that the image is crucial to any inquiry of science, it is not convincing unless something more is added. This paper intends to demonstrate this needed part by an application of Lakatos’ distinction between ‘internal history’ and ‘external history’ explicated in his rational construction of the history of science. We attempt to manifest that the ideas Lakatos gained from the Hungary political practices are not ‘external’ and hence have to be ‘internalized’ in the philosophical development of his ideas. Once the ‘internalization’ is carried out, we will be better situated to fully comprehend the profound meaning of Lakatos’ philosophy of science.(jjyuann@mail.thu.edu.tw)

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intereshttp://www.sunspot.noao.edu/sunspot/pr/science-main.html

What Is Science?Science is a method of finding explanations of how anything in the world or universe works or came to be, by figuring out which explanation best predicts what actually happens, or best fits the observations

You can read all about it below, or you can first test your scientific skills. Are you a scientist?

The scientific way often works somewhat as listed below.

In science, some observation lies at the basis of many new bits of knowledge: The scientist sees something happening and wonders why it happened at all or why it happened just that way. Then the scientist thinks up one or more hypotheses: ways to explain what happened. Sometimes scientists invent a hypothesis not based on any direct observations. Such hypotheses are sometimes derived from "What if ...?"-questions, such as "What if the Earth were flat instead of round?". Each hypothesis predicts what will happen in some specific case. Next, the scientist thinks of and performs one or more experiments: ways to test the hypotheses and see which one best predicted what happens. Sometimes (for instance, often in astronomy) one cannot do direct experiments. Then one has to make do with statistical experiments that study many existing or new records of the topic of your hypothesis.

And finally, the scientist notes which, if any, of the hypotheses fits the outcome of the experiments. It might be that one of the hypotheses fits the results of the experiments, or that more than one of them fit, or that none of them fit. If any of the hypotheses fits the results of the experiments, then that hypothesis is assumed to tell us something about our universe. If none of the hypotheses fits, then the scientist discards all of them and has to invent new hypotheses. If more than one fits, then the scientist needs to invent new experiments that can tell the difference between the hypotheses.

Hypotheses, Theories, Laws, and Models"Hypothesis" and similar words does not mean the same thing to all people. In daily life, "hypothesis" means an explanation for which there is no or hardly any evidence ("It's only a hypothesis") but which the person that discusses it thinks to be true ("What's your hypothesis or theory about what happened here?"). "Theory" is used for the same thing, but often means that there is more evidence for it. A "law of nature" is a statement about a relation between things in nature that has been found to be always true (under certain conditions that are implicitly part of the law). For instance, it's called a law of nature that things always fall toward the ground, and never upward.

In science, "hypothesis" does not say anything about how much evidence there is for the explanation or what the inventor thinks is true. A hypothesis is whatever explanation or statement is being tested in an experiment. If I want to test the proposition that gravity makes things come down, then that is my hypothesis. If instead I want to test the assumption that gravity makes things fly away, then that is my hypothesis.

Theories and laws of nature in science are comparable to their counterparts outside of science, but are generally stated with much more precision and detail. For instance, the scientific form of the law of gravity is that (if no other forces are present) objects attract each other with a force that is proportional to the product of the masses of the objects and inversely proportional to the square of their mutual distance. On Earth, this makes things fall toward the ground, just as the daily-life form of the law says, but the scientific law allows one to calculate how fast things fall and where they land.

If you combine a large number of scientific hypotheses about a particular object (such as a black hole) then you have a model of that object. Model making is a favorite passtime of many scientists.

There are a couple of things to remember when reading, thinking about, or doing science:

Science makes detailed predictions that can be accurately tested. By keeping the hypotheses whose predictions work the best and throwing away the hypotheses that don't predict so good scientists keep improving their knowledge. In empirical science, there is no "absolute truth", and nothing is "self-evident". There are only hypotheses at various levels of trustworthiness. Any claim or hypothesis is only as good as the evidence that there is for it (and the lack of evidence against it), and only tests of predictions that were made based on the hypothesis count as evidence for or against the hypothesis. Science tries to find out how things are or come to be, regardless of anyone's belief of how things are, or anyone's opinion of how things should be. You can only find out how things are by studying them. Of course, which things scientists investigate and which

hypotheses they think of to test may depend on their beliefs, but their conclusions should not depend on their beliefs, just like different mountain climbers agree where the top of each mountain is, even though they may get there by different routes. Science invites anyone to try to prove that any of its claims are wrong. Scientists are expected to accurately describe all the evidence for their claims and how they got that evidence, so that anyone else (for instance, people who don't believe the results) can try to do the exact same experiments to see if they find the same answers. If many people try to prove some scientific hypothesis to be wrong but fail, then the hypothesis gains trust and becomes more useful. If any one person proves some aspect of a scientific claim to the wrong, then we can adjust the hypothesis and improve its predictive power (and therefore its usefulness).

This built-in error correction makes science different from many other systems of claims to knowledge or world views.

Not all hypotheses are equally useful. A hypothesis is useless to science if it cannot conceivably be proved wrong (for instance, "Your hair turns green but only as long as nobody's watching"). Scientists say that a hypothesis must be falsifiable. Not all experiments are equally good. The experiments should be able to tell the difference between the hypotheses. If each of the hypotheses predicts the same outcome for an experiment, then that experiment cannot help us find out which of the hypotheses is the best. If a hypothesis fits the facts in one or a set of experiments, then that does not mean that the hypothesis is correct in all cases - or even correct at all. Usually a set of experiments does not cover all possible combinations that the hypothesis applies to, and the supposed correctness of the hypothesis in all of its possible cases is inferred by induction. In addition, there may still be other hypotheses that explain the observations equally well. You cannot use an observation both as a basis and as evidence for a hypothesis. You can only test a hypothesis by predicting the outcome of some experiment and then checking whether the prediction has come true. Absence of evidence is not evidence of absence. Sometimes science cannot decide one way or the other whether something is true or not. Science is performed by people, so unfortunately there is some bad science between all the good science.

As an example of how science works, I have a description of how the possibility and properties of black holes were discovered.

Diccionario

Cómo se hace una hipótesis?Por Hugo Müler.

Cuando se emprende una investigación científica, al postular o formular una hipótesis conviene remitirse al sentido original y común de la palabra, entendida como suposición o conjetura provisional acerca de algún fenómeno u objeto de estudio, y que tiene como función principal delimitar el problema a investigar, teniendo en cuenta algunas variables que naturalmente refieren a las características propias del fenómeno investigado.

Desde una perspectiva etimológica, el término hipótesis deriva del griego, upo, que significa 'lo que se pone a la base de algo', lo cual remite a la idea de apoyo de algo, en el mismo sentido del término latino suppositio, suposición. Esta definición permite un primer acercamiento intuitivo al concepto de hipótesis y su utilización en el campo científico. Por lo general, se formula una hipótesis como una forma de predicción que describe de un modo concreto lo que se espera sucederá con determinado objeto de estudio si se cumplen ciertas condiciones (por ejemplo, al lanzar un plan piloto escolar que incorpora nuevos métodos didácticos).

Es a Galileo Galilei a quien se le adjudica la creación del método experimental hipotético-deductivo, del cual deriva el empleo consciente de las hipótesis y su inserción orgánica y funcional en el método científico. En la lectura de Dialogo sopra i due massimi sistemi del mondo (1632) y Discorsi et dimostrazioni matematiche intorno a due nuove scienze se plantean los pasos a seguir en el desarrollo de una investigación científica, que en síntesis son los siguientes:

1) Se determinan los datos de observación.

2) El investigador concibe una hipótesis explicativa de los datos observados.

3) El investigador desarrolla algunas consecuencias o efectos concretos que derivan de la hipótesis formulada.

4) Trata de averiguar experimentalmente si estas consecuencias que ha inferido responden a hechos reales.

Formulación de hipótesis

En la formulación de la hipótesis se deben emplear términos claros y concretos, de modo que puedan ser definidos de modo operacional, a los fines de que otros investigadores puedan refutar o corroborar la investigación realizada. Por lo tanto, toda hipótesis, en el campo de la investigación científica, debe estar sujeta a referencias y a una contrastación empírica. Por otra parte, deben ser objetivas y no se pueden incluir en ellas juicios de valor, del tipo que tal elemento o condición es "mejor o peor" que otro, sino simplemente plantearse tal como el investigador objetivamente postula que el fenómeno estudiado sucede en la realidad.

Otro punto importante en la formulación de la hipótesis es la especificidad, de tal modo que se determinen los indicadores a emplear para medir las variables estudiadas. Asimismo, la hipótesis debe ser afín con los recursos y las técnicas de investigación disponibles, puesto que de su alcance y limitaciones dependerá la comprobación de la misma, y a la vez, debe sostenerse a partir del marco teórico empleado en la investigación, el cual brinda un soporte también para el análisis una vez que se inicie el proceso de contrastarla con los datos derivados de la metodología empleada para su contrastación. Es así que la hipótesis debe ayudar a la explicación de los fenómenos estudiados a partir de las relaciones que establece entre variables.

Tipos generales de hipótesis

Hipótesis nula: La hipótesis nula se utiliza en toda investigación en que se estudian las características de dos o más grupos, siendo aquella que establece que no existen diferencias significativas entre los grupos. Por ejemplo, un investigador se propone verificar una hipótesis, la cual sostiene que la práctica de ajedrez mejora el rendimiento escolar de los alumnos de escuela primaria. Para ello, divide al azar una muestra de niños en dos grupos: uno que denominará experimental, el cual recibirá clases intensivas de ajedrez durante un mes, y otro que se llamará grupo control, que no recibirá clases del "juego ciencia". En este caso, la hipótesis nula será aquella que postula que no habrá diferencias en el rendimiento escolar entre el grupo que recibió las clases y el que no la recibió.

La importancia de la hipótesis nula radica en que es de directa comprobación, o sea, se acepta o se rechaza según el resultado de la prueba realizada, además de contribuir a determinar las diferencias entre los grupos sometidos a prueba (el experimental y el de control), y si dichas diferencias son significativas.

Hipótesis conceptual: Es la hipótesis que se formula en base al marco teórico aplicable al problema de investigación, y debe explicar desde alguna perspectiva el fenómeno estudiado. Este tipo de hipótesis orienta la investigación focalizando el problema como base para la búsqueda de datos que la corroboren o refuten, y debe ser acorde con los objetivos propuestos. Se puede enunciar como relación causal o determinante derivada del planteamiento del problema, e implicar variables comprendidas en el marco teórico.

Hipótesis de trabajo: Es la hipótesis que responde a las inferencias o creencias del investigador, es decir, aquella que utilizará para dar una explicación al fenómeno investigado, y que de algún modo se contrapone a la hipótesis nula. En otros términos, la hipótesis de trabajo es operacional, ya que muestra cuantitativamente lo planteado en la hipótesis conceptual.

Hipótesis alternativa: En toda investigación científica resulta más que conveniente proponer una hipótesis alternativa en la cual se incluyan variables independientes distintas de las que aparecen en la hipótesis de trabajo. De este modo se podrá contar con respuestas alternativas al problema de investigación, que tomen en cuenta otras variables y condicionamientos que también deberían estar sujetos a una comprobación.

Hipótesis estadística: En el campo de la utilización y aprovechamiento de la estadística, las decisiones se toman siempre sobre determinadas hipótesis. La eficiencia de las campañas publicitarias o de los proceso de producción se fundan en criterios numéricos,

y tales hipótesis se expresan en función de parámetros estadísticos. En el análisis de todo problema de investigación, la contrastación de una hipótesis dada se realiza aceptando o negando una alternativa lógica. Cuando se estudian fenómenos que obedecen a leyes estadísticas se busca establecer relaciones numéricas bastante regulares, siendo más significativa esta regularidad cuando mayor es el número de fenómenos o la población (el alcance de su carácter cuantitativo), perdiendo validez el criterio estadístico cuando la muestra tiende a ser poco representativa desde una perspectiva numérica: Las condiciones que se requieren para aplicar hipótesis estadísticas son las siguientes: a) una gran masa de elementos, b) independencia de estos entre sí, c) el establecimiento de una relación de causalidad.

Hipótesis causal: Toda hipótesis plantea una relación funcional entre variables. Esta relación puede ser causal, cuando una variable produce un efecto determinado sobre otra variable, o correlacional (cuando las variaciones de una se relacionan de algún modo con las variaciones de la otra). En una hipótesis que sustenta una relación causal, las variables se llaman dependiente e independiente. La variable que se supone causa el efecto en la otra -manejada por el investigador-, es la variable independiente, y sobre la que se produjo el efecto es la variable dependiente. La modificación entonces de la variable independiente produce un cambio en un parámetro (probabilidad, magnitud o frecuencia) en determinada variable dependiente. Cuando se pretende contrastar una hipótesis causal, el cambio que una variable produce en otra, se deben modificar los valores de la primera variable, independiente, y registrar si los valores de la segunda variable cambian en consecuencia. Un ejemplo de hipótesis causal sería: "La rebaja del precio de las entradas a las canchas de fútbol produce un aumento de los concurrentes a los estadios".

Hipótesis correlacional: La formulación de hipótesis correlacionales supone la evaluación de la relación entre variables. La investigación correlacional tiene de por sí un valor explicativo, ya que saber que dos conceptos o variables se relacionan de determinada manera, aporta información explicativa que establece una relación entre variables (en una correlación que puede ser múltiple), sin necesidad de plantear cómo se dan estas asociaciones. En una hipótesis correlacional, por lo tanto, no importa tanto el orden en que se coloquen las variables. A determinadas condiciones de prueba o contrastación, se busca ver cómo se comportan las variables objeto de estudio.

Las hipótesis también se diferencian de acuerdo con el tipo de investigación al cual responden o desde donde son formuladas.

En las investigaciones exploratorias el objetivo suele ser más modesto en términos científicos, y se trata simplemente de obtener datos que permitan la formulación o la elaboración de una hipótesis. Por tanto, una hipótesis planteada en una investigación exploratoria puede resultar más flexible y ser un tanto menos precisa. Si bien existen metodólogos que niegan la posibilidad de plantear una hipótesis en investigaciones exploratorias -ya que al tratarse la investigación de un objeto de estudio en principio desconocido por el investigador, por consiguiente no pueden establecerse hipótesis de un fenómeno desconocido-, otros autores clasifican a estas hipótesis como heurísticas, que están propuestas con el fin de encontrar algo nuevo o descubrir otras hipótesis más generales o sugestivas. Presentamos a continuación un ejemplo de una hipótesis que se da en el marco de una investigación exploratoria que tiene como objeto de estudio a las empresas de Internet chilenas, y el volumen de operaciones que concretan a través de e-

commerce, siendo la hipótesis la siguiente: "Las empresas .com chilenas no han desarrollado estrategias para aumentar el caudal de operaciones que realizan por Internet".

Las investigaciones descriptivas presentan hipótesis más precisas, y por lo general dan cuenta de diferentes tipos de relaciones. A continuación describimos en forma sucinta cuáles son las hipótesis que es posible formular en una investigación descriptiva. En principio, la relación se da a partir de determinadas características que presenta el objeto de estudio, por ejemplo, "en las zonas más empobrecidas de México hay un notorio rezago educativo y altos índices de analfabetismo". También, en este tipo de investigación, la hipótesis puede plantear una relación del tipo "X pertenece a Y o a Z". En este caso, se describe al objeto de estudio incluyéndolo en un orden superior. Un ejemplo de esta relación se manifiesta en la siguiente hipótesis: "Los funcionarios y directivos de organismos públicos en la Argentina aplican los mismos criterios y políticas administrativas en boga en el ámbito privado (las mismas recetas neoliberales)". Por último, la hipótesis de una investigación descriptiva se puede construir a partir de una relación entre variables, en una ecuación del tipo "X produce (o afecta) a Y de determinada manera", y un ejemplo de este tipo de relación planteada en una hipótesis sería "En Venezuela, el nuevo régimen aduanero y el control ejercido por las nuevas leyes tributarias reducen los casos de contrabando".

Es en las investigaciones explicativas donde resulta imprescindible formular con suma claridad las hipótesis de la investigación, dando cuenta de las variables intervinientes, su conexión y su incidencia en el fenómeno investigado. En el desarrollo de una investigación explicativa, antes de formular la hipótesis se debe evaluar la adecuación del marco teórico utilizado, asegurarse de que se hace una utilización lógica de dicho marco y tener en cuenta las técnicas de investigación a emplearse en la conformación de la hipótesis. Generalmente, al intervenir dos o más variables, en la formulación de la hipótesis se suele recurrir a la estructura "si se da tal condición, entonces se producirá determinado efecto o resultado", si X, entonces Y, bajo las condiciones R y S. A continuación, un ejemplo de este tipo de relación, que es la más compleja que se da en las investigaciones explicativas: "La situación de desempleo, el aumento de las olas inmigratorias, y la mejoría de las condiciones laborales en las Fuerzas Armadas Españolas ha provocado un aumento de los inscriptos a ingresar como soldado profesional en los últimos años".

Bibliografía

Coraminas, Joan. Diccionario Etimológico de la Lengua Castellana. Gredos, Madrid, 1997.

Sabino, Carlos A. El Proceso de Investigación. Buenos Aires. Ed. Lumen - Humanitas. 1996.

Tenorio Bahena, Jorge. Investigación Documental. 3ª ed. México. Ed. Mac Graw - Hill. 1988

Tamayo, Mario. El Proceso de la Investigación Científica. 3ª ed. México Ed. Limusa S.A., 1998.

Más diccionario

HipótesisSe trata de un término procedente del griego que designa, etimológicamente, "aquello que se encuentra debajo de algo sirviéndole de base o fundamento". A nivel más simple, una hipótesis es un planteamiento inicial cuya validez ha de ser confirmada por la experimentación o el razonamiento.

En lógica filosófica, se entiende por hipótesis un enunciado (o un conjunto de enunciados) que precede a otros enunciados y constituye su fundamento. Asimismo, puede definirse como una proposición cuya verdad o validez no se cuestiona en un primer momento, pero que permite iniciar una cadena de razonamientos que luego puede ser adecuadamente verificada.

Un razonamiento por hipótesis es el que comienza suponiendo la validez de una afirmación, sin que ésta se encuentre fundamentada o sea universalmente aceptada.

La formulación de hipótesis adecuadas y correctamente fundamentadas en la experiencia es uno de los rasgos esenciales del método científico, desde Galileo e Isaac Newton.

Sobre el nacimiento de la ciencia

Una primera relación establecida entre objetos, sucesos y condiciones de lo que llamamos ciencia -vista ésta desde una panorámica puramente temporal- habrá de llevamos a localizar o rescatar tres posturas que podemos considerar filosóficas, y que habrán de mostrar diferencias de fondo al compararlas con las ideas que en otros tiempos, para cada una de ellas, estaban comúnmente aceptadas.

La primera de esas posturas queda situada explícitamente en el mundo griego, unos cuatro o cinco siglos antes de Cristo, cuando filósofos como Anaxímenes, Anaximandro, Empédocles, Heráclito, Tales de Mileto y otros, cada quien a su modo, proponen una respuesta diferente a la que entonces se admitía como válida para la antigua pregunta sobre la composición del universo. Aire, agua, fuego y tierra... sabemos hoy que no son los elementos constitutivos de aquél, pero no es eso lo importante; lo que hace verdaderamente trascendente su respuesta no es lo explícito, no es lo propuesto en primer término, no es la propuesta directa: es lo que se excluye lo que da valor a esa postura! Ninguno de ellos, sabios o filósofos, habla de titanes, del Olimpo, de Cronos, de Zeus; todos ellos se refieren siempre a un elemento de la realidad, a una parte de la naturaleza, a un ente objeto o partícula que se puede examinar objetivamente, y verificar o medir si es o no verdadero. ¡En eso estriba su importancia para la ciencia!

La segunda postura subtiende un amplio periodo de consolidación; importa en ella una característica fundamental: la sustitución de las grandes preguntas (¿Quién construyó el universo" ¿Cuál es el destino del hombre?, etc.) por otras más simples, alcanzables, interrogantes que eran y continúan siendo susceptibles de respuesta), verificación física. Este cambio en la manera de pensar se traduce también en algo trascendente: hace que la filosofía, reina única del conocimiento, tome el lugar que habría de corresponderle.

Aparecen entonces -valga la expresión- los precursores de las diferentes ciencias actuales.

Por último, no obstante que la renuncia a las grandes preguntas era necesaria, no era suficiente para el surgimiento de la ciencia. Hacía falta otra renuncia: la de considerar a la razón, al principio de consistencia lógica interna, como único medio de descubrir la verdad de los fenómenos naturales.

Sobre Galileo

Como principal mérito de Galileo se tiene el descubrimiento del método experimental propiamente dicho, más importante aun que sus descubrimientos en los campos de la mecánica y de la astronomía. Galileo, dice E Amerio "...nos parece el primer gran científico de la edad moderna; ha creado la ciencia teorizando su naturaleza y su método, teniendo conciencia del problema del método y de la naturaleza de la ciencia".

En cuanto al método, pensemos que, si bajo alguna circunstancia se presentara la necesidad de indagar sobre la caída libre de los cuerpos, podríamos hacerlo siguiendo alguno de estos dos caminos:

a) Experimentar, anotar los resultados obtenidos y encontrar una ley congruente con tales resultados.

b) Proponer a priori tal ley y observar si es verificable por la experiencia

De la segunda manera es como procede Galileo, y esto se conoce porque es en sus trabajos sobre la caída libre de los cuerpos donde "dibujó" la marcha del pensamiento que lo lleva finalmente a la verificación de la ley propuesta: e = 1/2 (gt.t).

A Galileo se le considera el creador del método experimental hipotético-deductivo, del cual resulta el empleo consciente de las hipótesis y su inserción orgánica en el método científico. En la lectura de sus escritos Dialogo sopra i due massimi sistemi del mondo (1632) y Discorsi et dimostrazioni matematiche intorno a due nuove scienze se observa que los pasos seguidos durante el desarrollo del estudio reproducen las sucesivas etapas del método hipotético-deductivo, a saber:

1) Ante los datos de observación. 2) El científico concibe una hipótesis explicativa. 3) Después, desarrolla algunas consecuencias concretas que se siguen de la hipótesis y 4) Trata de averiguar experimentalmente si estas consecuencias que se ha imaginado son hechos reales.

Como un aspecto a destacar, resulta ventajoso en este método que los hechos a verificar en la cuarta de las etapas discrepen de los que dieron inicio al proceso al formar la hipótesis, y que no puedan confundirse de alguna manera, porque ello va a permitir, de alguna manera, verificar la pertinencia de la hipótesis en un tiempo prudente.

Es necesario explicar que observar y experimentar son acciones diferentes. J.J. Ziminermann se expresaba así a este respecto: "...Un experimento difiere de una observación en que el conocimiento que una observación nos procura parece presentarse por sí mismo, mientras que el que nos suministra un experimento, es fruto de una

tentativa que se hace con el deseo de saber si una cosa es o no es... " C. Bernard cita que: "...La observación sería la comprobación de las cosas o de los fenómenos, tal como nos los ofrece ordinariamente la naturaleza, mientras que el experimento sería la comprobación de los fenómenos provocados o determinados por el experimentador" , proponiendo él mismo que la observación puede ser activa o pasiva. Asimismo, señala que un investigador científico puede ser observador y experimentador, siendo observador aquél que aplica los procedimientos de investigación simples o complejos al estudio de fenómenos que no hace variar y que, por consiguiente, recoge tal como se los ofrece la naturaleza, mientras que el experimentador es el que emplea los procedimientos de investigación simples o complejos, para hacer que los fenómenos naturales varíen o se modifiquen con un fin cualquiera, haciéndolos aparecer en condiciones en que no los presenta la naturaleza.

En este sentido, "el experimentador" reflexiona, ensaya, combina, compara a fin de encontrar las condiciones experimentales más apropiadas para alcanzar el objeto que se propone. En cambio, "el observador" comprueba pura y simplemente el fenómeno que tiene a la vista; es como el fotógrafo de la naturaleza, pues su observación busca representar exactamente a ésta.

La observación tiene lugar en las ciencias donde no es posible reproducir a capricho del científico los fenómenos que se han de estudiar. Cabe señalar que ciencias como la astronomía o la cosmología, consideradas como ciencias de observación (así definió Laplace a la astronomía), es posible incluírlas como ciencias activas si el observador emplea una metodología científica como la utilizada, por ejemplo, en el descubrimiento de Neptuno, o la usada en estudios de cosmología: agujeros negros, masa del universo, formaciones galácticas lenticulares, etc. En esos estudios podemos observar que la comprobación, como último estadio del método hipotético deductivo, no es un experimento sino que éste fue sustituido por una observación activa.

Hipótesis científica, hipótesis de trabajo

El método científico reposa sobre la comprobación experimental de una hipótesis científica, comprobación que puede ser obtenida unas veces por la observación (descubrimiento de Neptuno) y otras por el experimento. La hipótesis científica no solo sirve como instrumento para la investigación, sino que se presenta como una conjetura verosímil de la realidad y una anticipación probable de la verdad, necesariamente fundada en una observación anterior. No hay reglas que se puedan ofrecer para hacer que, como consecuencia, de una observación dada, nazca una hipótesis justa y fecunda; tampoco hay métodos para ello; más bien parece que su aparición es de "chiripa", espontánea o de improviso, de naturaleza individual por completo.

La palabra hipótesis, derivada del verbo griego hypotithemi, colocar debajo, significa etimológicamente base, principio fundamental, tal como sería usada en matemáticas. Pero en la ciencia experimental el término hipótesis se toma en el sentido de explicación provisional de los hechos que requiere ser verificada. Si se tratara de aspectos de matemática pura, entonces, como se señala renglones antes, se considera como principio fundamental y éste habrá de demostrarse.

En 1959 C. Gini escribía: 'Los éxitos obtenidos por la física han ceñido de una aureola el método hipotético-deductivo, el que consiiste en hacer una hipótesis provisional llamada hipótesis de trabajo, y en verificar después, sobre los hechos, las deducciones que se sacan de ella; aceptándola en definitiva, modificándola o rechazándola según lo que sugieran los resultados obtenidos por la verificación. Aun en el caso que la hipótesis de trabajo no fuese comprobada, resulta valiosa si orienta e impulsa la investigación en el descubrimiento de nuevos o diferentes fenómenos". En el campo de la ciencia, una hipótesis bien seleccionada contribuye poderosamente al desarrollo de ella, lo cual es innegablee; pero la desaparición, sustitución o fusión de dos hipótesis tiene una importancia todavía mayor. cuanto más restringido es el número de hipótesis tanto más avanzado está el desarrollo de la ciencia. Según Ostwald, la ciencia "...no intenta establecer hipótesis, sino eliminar las que existen". La ciencia habría alcanzado su objeto si no contuviera más que una sola hipótesis, de donde fluyera como consecuencia necesaria la ley de dependencia de todos los fenómenos del mundo exterior. (Como ejemplo la búsqueda de la teoría del campo unificado de A. Einstein).

Ley, teoría y modelo

Una ley, antes de serlo, fue hipótesis, pero ésta fue verificada por los hechos. Las leyes físicas son proposiciones que expresan modos constantes de verificarse los fenómenos en determinadas circunstancias.

El método hipotético- deductivo de Galileo presenta otra novedad: en él, la ley reviste forma matemática. Será típico de la ciencia el estudio de los aspectos cuantitativos del mundo material, y es que la medición de los aspectos cuantitativos de los cuerpos trae la posibilidad de descubrir una relación constante entre ellos. Tal relación constante, expresable en términos matemáticos, constituye una ley.

La ley que liga unas con otras diversas magnitudes medibles, reviste matemáticamente la forma de un enlace de tipo funcional (dando valores a la variable independiente se encuentra el valor de la variable dependiente) y el valor así calculado debe corresponder, dentro de los limites de los errores experimentales, al valor que resultaría de una medición directa de esa magnitud.

Leyes

De manera general venimos aceptando que una ley física es un enunciado o proposición que expresa modos constantes de verificacíón de los fenómenos en determinadas circunstancias. Ampliando esa idea, habremos de distinguir dos clases de leyes: cualitativas, que sólo afirman la existencia de un hecho en determinadas circunstancias, vgr. cuando un cuerpo se calienta, éste se dilata, o bien, los rayos de luz al pasar de un medio a otro de diferente densidad cambian de dirección, o también, los rayos de luz blanca, al atravesar un prisma se descomponen en los colores del espectro. Y leyes cuantitativas, que se refieren a la dependencia constante de índole cuantitativa entre determinadas magnitudes variables con las que la ciencia intenta conocer la realidad por lo que en ésta hay de cuantitativo, siendo la medición el procedimiento fundamental de establecer esas magnitudes.

Ley estadística

Aplicado inicialmente en el estudio de eventos sociales, y luego en los juegos de azar, el cálculo de probabilidades ha llegado a tener como herramienta matemática para captura de información un valor indiscutible; su uso en la actualidad se ha extendido a prácticamente todas las ciencias. D. Papp dice al respecto: "El cálculo de probabilidades parte del azar, lo avasalla, lo encadena y logra encontrar nuevas leyes". Los métodos estadísticos y el cálculo de probabilidades permiten al estudioso captar con gran exactitud el comportamiento medio de una colectividad de eventos, sean éstos choques de moléculas sobre las paredes del recipiente que las contiene, desintegración atómica de un elemento radiactivo, o grupo de votantes en una elección presidencial, el diseño de un presupuesto gubernamental o la estandarización de un test.

Según L. von Bortkiewicz, leyes estadísticas son "ciertos resultados de la estadística, ciertos números relativos o medios que se distinguen por su constancia o su estabilidad aproximada", o dicho en otros términos, ley estadística es el enunciado de constancia o regularidad de que dan muestra las colecciones de casos. Una ley estadística se deduce de tablas o concentrados organizados de numerosas observaciones, llamados también masa estadística, o sea, una multitud de fenómenos de seres o eventos que tienen alguna regularidad.

Cuando se estudian los fenómenos que obedecen a leyes estadísticas se advierte que es posible definir, entre estos fenómenos, relaciones numéricas bastante regulares, apareciendo la regularidad de manera más significativa cuanto más con 1derable es el número de fenómenos, de tal manera que a un número mínimo de fenómenos, esa ley ya no tiene sentido. Las condiciones requeridas para que pueda darse una ley estadística son:

a. Una nutrida masa de elementos.

b. Independencia de ellos entre si.

c. Casualidad.

Teoría

Por lo escrito en párrafos anteriores, podemos intuir que las leyes ponen de manifiesto cierta regularidad, constancia o legalidad descubierta en la naturaleza. El enunciado de una ley, como descripción de las relaciones constantes entre los fenómenos, es uno de los objetivos más inmediatos de la ciencia, y la presentación de la misma en forma de función matemática es indispensable para el logro del progreso científico, pero la comprensión y explicación de los fenómenos es en sí el interés primordial de la ciencia; de aquí la existencia de las teorías en los dominios de ésta.

En lo general, podemos entender que una teoría responde a esa necesidad constante en el hombre de contestar el cómo y el porqué de los fenómenos observados. La ciencia, escribía Albert Einstein reproduciendo a Mayerson, "...no se contenta con formular leyes de experiencia; más bien intenta construir un sistema lógico que se base en un mínimo de premisas y comprenda en sus consecuencias todas las leyes de la

naturaleza". Una teoría -continúa Einstein- "encuentra su razón de ser en el hecho de enlazar el mayor número de conocimientos aislados". "A lo que la ciencia tiende -dice ahora Mayerson de modo más inmediato es a establecer una relación lógica entre los fenómenos, y a deducirlos unos de otros".

Por teoría podemos entender un conjunto, lo más reducído,,posíble, de proposiciones, de las cuales puedan deducirse lógicamente las leyes experimentales. En el progreso de la ciencia hay que observar que siempre se va pasando a síntesis cada vez más generales, con el objetivo último de llegar a una teoría única que abarque todos los fenómenos naturales (en su caso).

Ahondando un poco en esas ideas, podemos decir que una teoría, en este caso física, es un sistema hipotético deductivo; un conjunto de hipótesis ligadas por la relación de deducibilidad o implicación (l-). En una teoría todo enunciado es una suposición básica (axioma o postulado), o una consecuencia lógica de fórmulas ya admitidas (a menos que sea una definición); lo que es importante resaltar es que estas teorías contienen suposiciones semánticas o hipótesis interpretativas que confieren un significado físico a sus símbolos básicos; las teorías físicas deben entenderse como formalismos físicamente interpretados. Esos formalismos requieren para serlo de una estructura tanto lógica como matemática.

Estructura lógica: Sabemos que cualquier enunciado bien formado es una fórmula de cálculo de predicados con identidad (CP =); ahora bien, desatendiendo momentáneamente a la estructura matemática fina, una teoría es, en cuanto a forma, un conjunto de fórmulas (F) del (CP

Además, para tener una teoría requerimos que (F) sea cerrado bajo deducción. Entonces, una teoría es una estructura relacional T=<F, l-> donde la relación es la de deducibilidad, la cual tiene las pro piedades de la relación de orden parcia K = ).

La relación (l- ) que ordena el conjunto (F) de fórmulas de una teoría científica (T) está caracterizada por las reglas de inferencia de (CP =), no siendo permisible romper la unidad de la lógica de la ciencia proponiendo una teoría que emplee algún sistema de lógica "no clásica ". Si otra lógica distinta subyaciera a una teoría científica, todas las demás teorías tendrían que ser reformuladas sobre la base de Ja misma lógica "no clásica", porque de otra manera Sería imposible aplicarlas conjuntamente a la explicación de los hechos y al diseño e interpretación de experimentos, ya que cada uno de esos procedimientos requieren de varias teorías diferentes.

Estructura matemática

Toda teoría que presuponga la matemática tiene, además de su estructura lógica, una estructura matemática, la cual no discierne la lógica por ser tan universal; incluso las teorías lógicas como el cálculo proposicional tienen una estructura matemática; la estructura matemática del cálculo proposicional es el álgebra Boleana. Las estructuras lógica y matemática de una teoría constituyen su estructura formal.

Modelo

Una teoría con una estructura formal Conocida es una teoría matemática mayor, o formalismo, a la que se le debe asignar una interpretación física si es que va a contar como una teoría física. Algunos teóricos consideran que las teorías, además de una estructura lógica y una estructura matemática, habrán de tener un tercer componente que es el modelo, que observamos en palabras de M. Bunge: "Una teoría abstracta es un sistema deduc1vo que contiene sólo símbolos no interpretados aparte de los lógicos; interpretando los símbolos básicos (primitivos) de una teoría abstracta, ésta adquiere significado. Cada teoría interpretada es llamada una realización o modelo de la teoría, si de hecho satisface los axiomas de la teoría. No hay limite al número de modelos de una teoría, pero estos deberán ser interpretaciones que respeten tanto la estructura de los conceptos como los axiomas".

Continuando las palabras de M. Bunge, se concluye que: "una teoría física es un formalismo dotado de una interpretación. El formalismo es un conjunto de fragmentos de teorías matemáticas y por lo tanto no tiene compromiso referencial: es la interpretación física la que coordina algunos de los símbolos matemáticos con propiedades de un sistema físico. Entendiendo que esta interpretación debe distinguirse de los medios por los cuales el valor de verdad de una teoría es aseverado".

El texto anterior, podemos considerar, de alguna manera finiquita las ideas sobre ciencia, hipótesis, ley, teoría y modelo, tan importantes al diseñar, desarrollar y defender un trabajo formal de investigación científica. La intención, se habrá observado implícitamente a lo largo de estos párrafos, es apoyar al docente en la otra de sus posibles labores: la investigación.

Quizá en otro trabajo estudiemos nuevos horizontes y posibilidades de la ciencia, ahora bajo puntos de vista más dirigidos al ámbito del comportamiento humano: el social-educativo.

Tesis

{f.} | thesis, dissertation, theme (Del lat. thesis); sust. f. [Nota: el plural es igualmente "tesis"].1. Proposición que una persona sostiene por medio de razonamientos: todas las tesis que expuso en la conferencia sobre la comunicación no verbal en los simios, fueron acreditadas por datos empíricos.2. Opinión de alguien sobre algo: nunca llegaremos a un acuerdo ya que sostenemos tesis muy distintas.3. Disertación escrita de investigación que se presenta ante un tribunal universitario para la obtención del título de doctor: se doctoró en Psicología con una tesis sobre el autismo.4. [Música] Golpe en el movimiento de la mano con que se marca alternativamente el compás.

Sinónimos

Razonamiento, argumento, proposición, exposición, testimonio, juicio, opinión, teoría, consideración, noción, suposición, interpretación, memoria, estudio, escrito.

Tesis -desde la filosofía-

El término "tesis" proviene del verbo griego tiqhmi, que significa "poner", por lo que el vocablo podría traducirse como "acción de poner". Aunque en principio podía ser cualquier cosa lo que se pusiera, en sentido más específico se usaba para significar la acción de "poner" una doctrina, principio o proposición. De esta forma se comprende la habitual traducción actual de "afirmación". En sentido todavía más específico, Aristóteles concibió la tesis como un principio inmediato del silogismo que sirve de base para la demostración. Se encuentra en el mismo nivel que el axioma, aunque difiere de éste en que la tesis no es un principio evidente e indemostrable, ni tampoco es indispensable para aprender algo, mientras que el axioma sí que lo es. También opina el filósofo griego que toda tesis es un problema, aunque no todo problema es una tesis. Y, por último, clasifica las tesis en dos clases principales: definiciones como aclaraciones semánticas de un término, y definiciones como posiciones de la existencia de una realidad, caso este último en que las tesis han de llamarse con más propiedad "hipótesis". Quintiliano contrapuso al sentido lógico que Aristóteles había dado al término "tesis" un sentido retórico, con el cual quería hacer hincapié en la fuerza de persuasión de ciertas afirmaciones. Ya en la modernidad, Kant, Fichte y algunas concepciones dialécticas (véase dialéctica) usaron el término "tesis" en un sentido técnico (véase, por ejemplo, antinomia en Kant). A este respecto, la tesis es uno de los momentos fundamentales del método dialéctico propuesto por Hegel, que se basa en la estructura triádica tesis-antítesis-síntesis.

Hipótesis

{f.} | hypothesis, supposition, guess. 2 [Filosofía] logical proposition. 3 [Lingüística] protasis, the clause expressing the condition in a conditional sentence (Del lat. hypothesis, y éste del gr. ÛpÕqesij); sust. f. [Nota: El plural es hipótesis.]1. Idea o suposición no demostrada a partir de la cual se pretende deducir una determinada consecuencia: tus hipótesis son muy atractivas, pero carecen de una base sólida.2. [Filosofía] Según la lógica tradicional, proposición particular incluida en la tesis.3. [Filosofía] Según la lógica moderna, fórmula de carácter transitorio que encabeza una deducción.4. [Lingüística] Prótasis o cláusula subordinada dentro de una oración condicional.

Modismos

Hipótesis alternativa. [Estadística] La opuesta a la nula. Hipótesis de trabajo. Suposición que sirve de guía en una investigación científica. Hipótesis nula. [Estadística] La que se hace sobre la población de la que se ha extraído la muestra o sobre la probabilidad que se considera que la representa.

Sinónimos

Suposición, supuesto, conjetura, presunción, idea, teoría, creencia, barrunto, proposición, cláusula, prótasis.

Antónimos

Realidad, verdad, efectividad, seguridad, apódosis.

Hipótesis -desde la filosofía-

Atendiendo a su origen etimológico, el vocablo "hipótesis" procede de los griegos qesiV ("tesis", "algo puesto") y upo ("debajo"), con lo cual podría traducirse como "algo puesto debajo", "lo que se pone debajo". Hablando de enunciados, la hipótesis sería un enunciado que constituye el fundamento de otros. Las cuestiones que más preocupan actualmente con respecto a las hipótesis son las que hacen referencia a su posible verificación o contrastación, a su posible clasificación y a la naturaleza del llamado "razonamiento hipotético". En su forma más simple, una hipótesis es un enunciado que se expresa mediante un condicional, acompañado de uno o varios enunciados que certifican si la consecuencia del condicional es o no verdadera, junto con una conclusión. Cuando se prueba que la consecuencia del condicional no es verdadera, entonces queda probado que el antecedente no es verdadero, con lo que hay que descartar la hipótesis; si, por el contrario, se prueba que el consecuente es verdadero, ello no es motivo suficiente para admitir la validez del antecedente (ya que las leyes de la lógica lo impiden), aunque la sucesiva confirmación de la verdad del consecuente puede llevar a la progresiva aceptación del antecedente desde un punto de vista intuitivo. Así, el fundamento más importante de aceptación de una hipótesis es, según muchos, su capacidad de predecir; aunque otros opinan que tal predictibilidad no es tan importante como la confirmación. Vistos los problemas lógicos que plantea tal confirmación, cabría preguntarse qué entienden los autores que así piensan por "confirmación". La respuesta es que "confirmación" puede entenderse de dos posibles modos: en primer lugar, una hipótesis se confirma más cuantos más ejemplos tiene; en segundo lugar, una hipótesis se ve confirmada cuando existen varios ejemplos que la apoyan en varias condiciones de cambio de las correspondientes variables. Pero, al margen de este significado general, lo cierto es que pueden encontrarse diferencias de matices en los usos que del término han hecho diversos autores a lo largo de la historia. Uno de los primeros autores en utilizar este término fue Platón, para quien una hipótesis es un supuesto del que pueden extraerse diversas consecuencias, como por ejemplo los supuestos que utilizan los matemáticos y geómetras. En este sentido, una hipótesis se distingue de un axioma en que este último es admitido como si se tratase de una verdad evidente, mientras que la hipótesis es más bien un postulado cuya verdad ha de probarse posteriormente. Aristóteles consideró el término "hipótesis" en dos sentidos principales; como un posible sinónimo de "principio" (así, por ejemplo, cuando habla de los "principios de la demostración"), y como una afirmación de la cual es posible deducir determinadas consecuencias. Además, este filósofo distinguió no sólo entre hipótesis y axioma, sino también entre hipótesis y postulado.Sin embargo, a pesar de estas menciones tempranas, lo cierto es que los autores antiguos y medievales no se preocuparon demasiado de dilucidar el significado de la hipótesis, y fue necesario esperar hasta la época moderna para que empezaran a abundar los análisis y reflexiones acerca de la naturaleza de este tipo de enunciados y, sobre todo, acerca de su posible justificación. Tal resurgir del interés por las hipótesis se vio motivado por el nacimiento de la física moderna, en el seno de la cual las hipótesis desempeñaban un papel fundamental. En este contexto, uno de los autores que más se ocupó de las hipótesis fue Newton, aunque, paradójicamente, parecía no tenerlas en muy buena estima. En efecto, en varios pasajes de su obra subraya que él no hace hipótesis (Hypotheses non fingo), y manifiesta entender por "hipótesis" todo aquello que no se

deduce estrictamente de los fenómenos, lo cual no tiene ningún sentido en el ámbito de lo que él llama "filosofía experimental". De cualquier forma, el sentido que el término "hipótesis" tiene en la obra de Newton ha sido objeto de diversas controversias por parte de los comentaristas, ya que algunos subrayan que, a pesar de su rechazo a "hacer hipótesis", lo cierto es que Newton las utilizó en algunos casos, como por ejemplo cuando propuso una causa de la naturaleza de la luz. Sea como fuere, reminiscencias de los planteamientos de Newton pueden encontrarse posteriormente en autores como Kant. Kant elaboró toda una teoría sobre la noción de hipótesis en su "Doctrina del Método", incluida en la Crítica de la Razón Pura. Allí afirma que las hipótesis no deben ser asunto de mera opinión, sino que han de fundarse en la "posibilidad del objeto". En este último caso las hipótesis son legítimas; no así en el caso de las llamadas "hipótesis trascendentales", que son simplemente una actividad de la "razón perezosa", que emplea una idea determinada sin darle una correspondiente explicación. Los autores positivistas, particularmente Auguste Comte, rechazaron la legitimidad de la utilización de hipótesis al identificarlas con la pretensión injustificada de formular enunciados que se refieran a causas, ya que para tales autores todo juicio relativo a las causas es hipotético, y las causas no pueden nunca descubrirse. Fraguar hipótesis es, según Comte, propio del pensamiento teológico y metafísico, pero no de un pensamiento positivo, que en lugar de buscar el "porqué", se limita a conocer el "cómo", lo único que puede conocerse. A pesar de que otros positivistas defendieron posiciones menos radicales que la de Comte, lo cierto es que la mayoría de ellos rechazaron las hipótesis cuando éstas se presentaban bajo la forma de especulaciones, pero las admitieron cuando se expresaban en forma de proposiciones condicionales y, en principio, verificables. En otro sentido, autores también positivistas como Ernst Mach, entre otros, han utilizado la expresión "hipótesis de trabajo", en el sentido de "explicación provisional" de un determinado fenómeno. La función de tales hipótesis sería comprender mejor los fenómenos de los que trata, sin necesidad de verse confirmada o refutada por los fenómenos, caso en el que dejaría de ser una hipótesis. En oposición a los autores que manifiestan su rechazo a la utilización de hipótesis, han existido también otros que consideran que las hipótesis científicas no sólo están justificadas, sino que son indispensables. Entre éstos pueden mencionarse a Whewell o Meyerson. En cuanto a la posible clasificación de las hipótesis, se han propuesto distintas posibilidades. Hugues Leblanc, por ejemplo, propone la diferenciación entre "hipótesis amplificadoras", que constituyen la conclusión de cualquier inferencia inductiva permisible con un enunciado de observación como premisa; e "hipótesis explicativas", que constituyen la premisa de alguna inferencia permisible con un enunciado de observación o una hipótesis como conclusión. El primer tipo de hipótesis se refieren a predicciones o retrodicciones de hechos y permiten ampliar nuestro conocimiento; las segundas, por el contrario, permiten conocer por qué determinado enunciado verdadero es tal, y permiten profundizar nuestro conocimiento.

Ciencia

La manera de proceder característica de la ciencia se ha dado en llamar el método científico. Bertran Russell (1969) señala que el método científico consiste en observar aquellos hechos que permiten al observador descubrir las leyes generales que los rigen., y describe así el proceso de investigación científica: "Para llegar a establecer una ley científica existen tres etapas principales: la primera consiste en observar los hechos significativos; la segunda en sentar hipótesis que, si son verdaderas, expliquen aquellos hechos; la tercera en deducir de estas hipótesis consecuencias que pueden ser puestas a prueba por la observación. Si las consecuencias son verificadas, se acepta provisionalmente la hipótesis como verdadera, aunque requerirá ordinariamente modificación posterior, como resultado del descubrimiento de hechos ulteriores."

No obstante hoy en día las concepciones modernas de la filosofía de la ciencia descartan la idea de que la observación y la experimentación sean un fundamento seguro y sostengan la ciencia. En esta línea están por ejemplo el radical Feyerabend (1974) y también Chalmers (1986:5), que afirma que "no hay ningún método que permita probar que las teorías científicas son verdaderas (...) no hay método que permita refutar de modo concluyente las ideas científicas". Y es que no puede afirmarse que la práctica del método científico elimine toda forma de sesgo personal o fuente de error, ni tampoco que asegure la verdad de las conclusiones. La epistemología (del griego "episteme", ciencia del saber absoluto, es el "estudio de la constitución de los conocimientos científicos que se consideran válidos" (Pérez Gómez, 1978:20). ) ha demostrado que el científico no es consciente de la totalidad de los factores (sociales, políticos, culturales e ideológicos) implicados en su actividad, ni sus propósitos y gestos son totalmente objetivos, ni las hipótesis son perfectamente conocidas y explícitas, ni su método totalmente transparente y protegido de toda influencia extraña. A partir de estas consideraciones, se va abriendo paso la idea de que el método científico consiste sobre todo "... en exponer una teoría (...) a la crítica constante y aguda del investigador. Sólo podrá seguir siendo válida una teoría que resista al continuo esfuerzo de falsación" (Von Cube, 1981:53)

Con todo, frente a Popper que afirma categóricamente que la ciencia avanza sobre la falsación de los enunciados que formula "todas la teorías son hipótesis tentativas, que prueban de ver sin funcionan o no. Y la corroboración experimental es sencillamente el resultado de pruebas realizadas con espítiru crítico, para saber donde yerran nuestras teorías"), otros autores como Kuhn propugnan que esta teoría de la falsación es errónea ya que propicia la supervivencia de muchas teorías ante la imposibilidad de rechazar muchas de las hipótesis que generan, y relaciona la madurez de una ciencia con la existencia de un paradigma ("una realización científica universalmente reconocida que, durante un cierto tiempo proporciona modelos de problemas y soluciones a una comunidad científica" según Kuhn) compartido por la comunidad científica, identificando la función de la ciencia no tanto con la exigencia de la conquista objetiva e imparcial de conocimientos, sino con la necesidad de dar pruebas fehacientes de su progreso. Un posicionamiento intermedio es el de Lakatos, que busca la objetividad de la ciencia a través de la objetividad de la metodología, pero coincidiendo con Popper en que son los datos los que propician los cambios teóricos. Para Lakatos lo que caracteriza a una teoría como científica es su capacidad para explicar hechos nuevos. En este marco, Sarramona (1991:257) apunta que "el conocimiento científico y la manera de

acceder a él son relativos y están en función de cada momento histórico, lo que nos debe motivar a seguir investigando permanentemente en la búsqueda de conocimientos cada vez más amplios y estables".

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UNAV encuentra Intelecto agente y el a priori formal kantianohttp://www.encuentra.com/includes/documento.php?IdDoc=2211&IdSec=405Rosmini, Balmes, Marechal,

Por José Angel García Cuadrado

1. La interpretación renovadora de Antonio Rosmini2. El escolasticismo ecléctico de Jaime Balmes3. La interpretación trascendental de Maréchal 4. La antropología trascendental de Rahner5. Conclusiones

Uno de los pasajes más controvertidos de la historia de la Filosofía antigua y medieval ha sido, sin duda, el capítulo V del libro III del De Anima. En este oscuro texto Aristóteles presenta la doctrina del entendimiento agente para explicar de qué manera la percepción sensible pasa a ser un conocimiento intelectual. La propuesta aristotélica fue ampliamente debatida por sus comentadores, con posturas dispares cuando no claramente enfrentadas. Sin embargo, en la filosofía moderna y contemporánea la doctrina del intelecto agente parece haber caído en el olvido; incluso dentro de la tradición escolástica de inspiración aristotélica se ha propuesto el abandono de dicha explicación gnoseológica.

¿Cabe todavía mantener la actualidad de la doctrina del entendimiento agente, o debe ser considerada como un objeto de estudio meramente arqueológico del pensamiento medieval? En mi opinión, recogiendo la afirmación del profesor García González, "en la filosofía moderna la doctrina del intelecto agente ha desaparecido. Pero su función gnoseológica no. Y Kant ha propuesto una dimensión a priori en el conocimiento intelectual, a su juicio pluralmente formal, pero derivada de la unidad de la conciencia trascendental; igual que Husserl, en nuestro siglo, ha buscado con la segunda reducción y en el ego trascendental el a priori del conocimiento intelectual. La doctrina del intelecto agente -concluye este mismo autor- es la versión metafísica tradicional del tema de la prioridad en el ámbito cognoscitivo intelectual". En mi exposición, dejaré a un lado el tratamiento fenomenológico y me detendré en la semejanza de la filosofía trascendental kantiana con la doctrina aristotélica del intelecto agente. Para ello me serviré de las interpretaciones de cuatro filósofos que de manera explícita han advertido los paralelismos entre entre ambas propuestas. Estos filósofos son: Rosmini, Balmes, Maréchal y Rahner. Los cuatro son pensadores católicos y conocedores de la filosofía escolástica, pero que buscaron la actualización de la filosofía aristotélico-tomista a partir de las aportaciones del criticismo kantiano.

1. La interpretación renovadora de Antonio Rosmini

Antonio Rosmini (1797-1855) publica en 1830 el Nuovo Saggio sulla origine delle idee, en abierto diálogo y confrontación con el empirismo y con el trascendentalismo idealista. A lo largo de su exposición, el pensador italiano percibe el paralelismo existente entre el "a priori" formal kantiano y la luz del intelecto agente. La postura rosminiana se puede comprender mejor desde la perspectiva renovadora en la que se

sitúa su filosofía. Así se entiende el intento de conciliar en la idea de ser la noción de lumen intellectus de la tradición, con el a priori formal kantiano. En efecto, Rosmini "cree que el punto neurálgico de toda la teoría del conocimiento debe situarse en torno a dos conceptos extremadamente próximos, cuando no coincidentes en el fondo: aquel del lumen mentis de la filosofía tradicional y el famoso a priori formal tan exigido en la alternativa kantiana". Para ello el pensador italiano propone una sugerente interpretación de la luz intelectual asignada al entendimiento agente. "Los principios innatos de Sto. Tomás, sean especulativos sean prácticos, están habitualmente insertos (habitus principiorum), y luego con ocasión de las sensaciones (phantasmata) son llevados al acto por el intelecto agente, y casi diría se recuerdan. Pero hay que observar, que el doctor de Aquino, además de estas nociones innatas en hábito, y no en acto, pone un intelecto agente, que está verdaderamente en acto, y que hace actualmente presente todas las cosas al pensamiento con su luz. Ahora bien, yo juzgo que esta luz del intelecto agente, que se expresa con el manto de la metáfora, y que no se encuentra en los escritos antiguos o raramente y como de paso, quitada la metáfora, es la idea del ser".La génesis de la afirmación rosminiana hay que buscarla en su intución fundamental, es decir, en la centralidad de la idea de ser. Para él, todo nuestro conocer viene mediado por la captación original, aunque no consciente, de la idea de ser: todo hombre al conocer posee la idea primigenia del ser universal, de tal modo que la idea de ser es lo primero que ontológicamente se necesita para conocer. Esa idea de ser es la única idea innata.Pues bien, en este planteamiento gnoseológico, la luz del intelecto agente viene a coincidir con esa idea innata del ser, en tanto que es un "medio de conocer el cual es como una luz que ilumina para la mente las cosas cognoscibles y este medio fue llamado por los antiguos filósofos «bajo el cual», medium sub quo". La luz del intelecto agente, es decir, la idea de ser, es puramente indeterminada y coexistencial al pensamiento.La semejanza con el "a priori" formal kantiano se puede advertir en la indeterminación del entendimiento agente como medio de conocer, que precisa de la sensación como materia o contenido sobre la cual actúa la luz del intelecto agente. Así lo explica el Roveretano: "si en nosotros se diese sólo la simple aprehensión, esto es, la pura idea, y no estuviese allí presente lo real, esto es, lo sentido, no se diría que nuestra mente entienda, sino sólo que tiene el medio de entender. Y tal es la condición de la mente que tiene sólo la idea innata del ser, sin ningún fantasma recibido del sentido: no se dice entonces que conoce algo, o que entiende algo, sino sólo que tiene la potencia de conocer y de entender".No obstante, para Rosmini, el intelecto agente no es sólo medio de conocer (obiectum quo cognoscimus), sino también y primariamente objeto conocido (obiectum quod cognoscimus). Este parece ser un punto central de la tesis rosminiana a juzgar por sus mismas palabras: "convencer al hombre de que ve esta luz en sí misma, la cual es –a la vez– principio de todo conocimiento, ha sido todo el objetivo del Nuovo Saggio". Y en otra ocasión dice: "La luz es algo que se ve, sin reducirse al ojo ni al acto de visión; es aquello que es visto y hace ver las cosas. Del mismo modo, la luz de la mente humana es un objeto visto, con el que se ve todo lo demás".En la propuesta rosminiana resulta interesante constatar de qué manera se percibe la relación existente entre el intelecto agente y el ser. La analogía de la luz se presentaba ya en la filosofía clásica ligada tanto a la luz intelectual del entendimiento agente como al acto de ser. No obstante, tal y como está formulada la propuesta rosminiana, ésta resulta un tanto ambigua. Parece difícilmente aceptable que la luz del intelecto agente

sea la idea de ser. En la tradición aristotélica el entendimiento agente es el principio activo que manifiesta, es decir, "hace ver la realidad" mediante su iluminación, pero este principio activo no se presenta en dicha tradición como una idea, ni mucho menos como una idea innata. En otras palabras, el intelecto agente es más bien un principio ontológico real y no meramente ideal. Se podría afirmar que el problema metafísico acerca de la prioridad intelectual lo resuelve Rosmini decantándose hacia un cierto idealismo; en efecto, la prioridad intelectual no es una acto, sino una idea innata. No me quiero extender más en este punto, puesto que sería preciso una exposición más completa de la interpretación rosminiana. No obstante, me interesa subrayar ahora el esfuerzo de Rosmini por conciliar en la idea de ser, la doctrina de la luz intelectual de la tradición con el "a priori" formal kantiano. Pero una vez expuesto el paralelismo de fondo, Rosmini marca las distancias con el criticismo. Es cierto que Kant ha tenido el mérito de haber visto la necesidad de informar la experiencia sensible y analizar minuciosamente este hecho, pero el defecto capital del filósofo de Königsberg consistiría en que con el método trascendental se examina sólo el acto por el que el sujeto conoce, sin reparar en el objeto que constituye en "acto primero" la mente misma. Esta limitación hace exclamar al filósofo italiano: "las múltiples formas de Kant tienen el pecado original de ser subjetivas". Así pues, la crítica rosminiana al sistema kantiano advierte la carga subjetivista de su planteamiento, lo que dificulta un verdadero conocimiento de la realidad objetiva. Esta podría ser, en síntesis, la valoración rosminiana de la gnoseología trascendental kantiana.

2. El escolasticismo ecléctico de Jaime Balmes

Jaime Balmes (1810-1848), comparte con Rosmini la preocupación por renovar la filosofía escolástica con las aportaciones filosóficas de la Modernidad. Durante los años 1842-1847 realizó diversos viajes que le permitieron entrar en contacto con pensadores franceses y más concretamente con el cardenal Mercier. El resultado de su filosofía puede ser denominado como un escolasticismo ecléctico, puesto que reconociendo la indudable autoridad de Santo Tomás, recibe influencias de Suárez, Leibniz y Descartes. En cuanto al método crítico kantiano, le reconoce un valor filosófico, siempre y cuando no sea utilizado de modo exclusivo.En su Filosofía Fundamental, publicado en 1848 pero elaborado durante sus estancias europeas, Balmes dedica todo el libro IV, a tratar de la génesis de la idea. El propósito fundamental del filósofo catalán es rebatir las explicaciones empiristas representadas por Condillac, el cual elimina las diferencias entre sensación e intelección reduciendo el conocimiento humano a percepción sensible. Frente al sensualismo de Condillac, Balmes acude a la doctrina aristotélica del entendimiento agente: "La escuela de los aristotélicos tomaba las sensaciones como punto de partida, pero no las consideraba como productoras de la inteligencia; por el contrario, deslindaba muy cuidadosamente entre el entendimiento y las facultades sensitivas, reconociendo en aquél una actividad propia, innata, muy superior a todas las facultades del orden sensitivo", y más adelante afirma que en la escolástica "se reconoce expresamente una actividad primordial de nuestro espíritu, no comunicada por las sensaciones, sino anterior a todas ellas. El entendimiento agente, (...) era una condenación permanente del sistema de la sensación trasformada, sostenido por Condillac".En efecto, en la gnoseología aristotélica "se hacía una separación entre el orden sensitivo y el intelectual, y como, por otro lado, era preciso establecer una

comunicación entre estos dos órdenes, si se quería salvar el principio de que nuestros conocimientos venían de los sentidos, fue necesario echar un puente que uniese las dos riberas (...) y éste fue el entendimiento agente". Balmes explica a continuación la iluminación de las imágenes sensibles llevada a cabo por el intelecto agente, y cómo éste las despoja de sus condiciones materiales. Y concluye: "Esta invención, más bien que ridícula, debiera llamarse poética, y antes merece el título de ingeniosa que el de extravagante. (...) Quítese a la explicación de las escuelas la parte poética, y véase si lo que en ella se envuelve vale tanto, por lo menos, como lo dicho por Kant al combatir el sensualismo". La autoridad de Kant le sirve a Balmes para refutar desde una perspectiva moderna, el sensualismo de Condillac, el cual no alcanzó ha notar "que las sensaciones por sí solas no bastan a explicar todos los fenómenos de nuestro espíritu, y que, además de la facultad sensistiva, era preciso admitir otra muy diferente, llamada entendimiento". Comienza entonces la comparación de la gnoseología kantiana con la aristotélica, "semejanza que tal vez no ha sido notada hasta ahora, no obstante de que salta a los ojos a la simple lectura del filósofo alemán". Balmes no parece conocer las obras de Rosmini, a pesar de compartir con él la idea de que se ha de abandonar el valor metafórico de la luz aplicada al intelecto agente para reconocer en el fondo la misma concepción kantiana. Según Balmes, el acierto de Kant es considerar "las sensaciones como materiales suministrados al entendimiento y que éste combina de varias maneras, reduciéndolos a conceptos. «Pensamientos sin materia, dice, son vanos, intuiciones sin conceptos son ciegas. Es, pues, igualmente indispensable el hacer sensibles los conceptos, esto es, darles un objeto en intuición, y el hacer inteligibles las intuiciones, sometiéndolas a conceptos» (Lógica trascendental. Introducción). ¿Quién no ve en este pasaje –continúa Balmes– el entendimiento agente de los aristotélicos, bien que expresado con otras palabras? Sustitúyase a intuición sensible, especie sensible; a concepto, especie inteligible, y nos encontraremos con una doctrina muy semejante a la de los escolásticos". Balmes, se detiene en establecer las concomitancias entre el sistema kantiano y el aristotélico, proponiendo una sugerente "traducción" de los términos kantianos al lenguaje escolástico. Sin embargo, Balmes también hace ver las profundas divergencias entre el planteamiento aristotélico y el kantiano. En la filosofía trascendental el conocimiento no puede traspasar el límite de la sensibilidad puesto que no es posible hacer un uso trascendental de los conceptos puros. La crítica de Balmes al sistema kantiano es tajante: "Difícilmente se puede encontrar doctrina más dañosa. ¿Qué le resta al espíritu si se le quitan los medios para salir de la esfera sensible? ¿A qué se reduce nuestro entendimiento si sus ideas más fundamentales y sus principios más elevados no tienen ningún valor para enseñarle algo sobre la naturaleza de las cosas? Si el mundo corpóreo no es más para nosotros que un conjunto de fenómenos sensibles, y nada podemos conocer fuera de ellos, nuestros conocimientos nada tienen de real, todos son puramente subjetivos, el alma vive de ilusiones y se envanece con creaciones imaginarias a las que nada corresponde en la realidad. Forma subjetiva el espacio, forma subjetiva el tiempo, conceptos vacíos las ideas puras, todo es subjetivo en nosotros; nada sabemos de los objetos". En definitiva, Balmes y Rosmini (aparentemente sin relación entre ellos aunque con un mismo afán renovador de la filosofía tradicional), advierten el paralelismo existente entre la doctrina aristotélica del intelecto agente y el "a priori" formal kantiano, pero no dejan de marcar las diferencias que se esconden en sus planteamientos fundamentales de orden ontológico.

3. La interpretación trascendental de Maréchal

La sugerente lectura llevada a cabo por Rosmini y Balmes, coincide en su propósito con la interpretación de Joseph Maréchal (1878-1944). El filósofo belga intenta asumir lo esencial del kantismo en el pensamiento escolástico: éste parece ser el hilo conductor de su gran obra, El punto de partida de la filosofía (la primera edición es de 1926). Para ello tratará de traducir al lenguaje crítico la terminología metafísica tomista.Al tratar de la doctrina del intelecto agente Maréchal apunta que se trata de una "verdadera teoría de la espontaneidad intelectual", con la cual se intenta conciliar la espontaneidad y la pasividad de la inteligencia, una cuestión gnoseológica típicamente kantiana. Poco después afirma: "Al estar siempre en acto, el entendimiento agente no tiene ninguna necesidad de un acto extraño para entrar en ejercicio: los efectos particulares de su «acto», es decir, las prolongaciones de su acto en «acciones», serán puestas o no según que ciertas condiciones formales extrínsecas se encuentren o no realizadas; pero su actividad, considerada en sí misma, es completamente a priori y espontánea" . Por lo tanto, según Maréchal, la actividad del intelecto agente es a priori porque es previa al inteligible en acto y previa a la sensibilidad. De esta manera el entendimiento agente pasa a pertenecer al sujeto trascendental como condición de posibilidad del conocimiento. Continúa el filósofo belga: "el entendimiento agente no basta, por sí sólo, para determinar al entendimiento posible; la parte verdaderamente espontánea de su intervención no sobrepasa ciertos caracteres absolutamente generales, cuya especificación próxima depende del fantasma. Kant decía lo mismo en términos críticos: el concepto no es totalmente a priori ni totalmente espontáneo: es a posteriori (o empírico) en cuanto a su materia (su contenido diverso), a priori y espontáneo en cuanto a su forma sintética (su forma de universalidad)". Para Maréchal el intelecto agente es un "a priori" del conocimiento humano, porque todavía no cuenta con la base empírica que hace posible el concepto. Y en este sentido, el entendimiento agente se debe colocar del lado trascendental, previo a la experiencia sensible y condición de posibilidad del conocer humano.En la concepción marechaliana del intelecto agente, se deja sentir también la noción del ser ideal de Rosmini cuando dice que el intelecto agente presenta "a priori" unos rasgos absolutamente generales e indeterminados, condición de posibilidad de todo otro conocimiento. Pero se distancia del filósofo italiano en que el intelecto agente no se pone de parte del objeto: "La actualidad del entendimiento agente difiere totalmente de la actualidad de un inteligible en acto, ya que no es, de ninguna manera, el objeto propio, conocido por el entendimiento pasivo". En otras palabras, el intelecto agente ilumina el objeto, pero no comparece en la operación. Con la tradición escolástica podemos decir que es medium quo cognoscitur, pero no objeto quod cognoscitur.Con todo, podemos concluir que la lectura de Maréchal coincide básicamente con las realizadas por Rosmini y Balmes. Sin embargo, no parecen advertirse en la interpretación merechaliana las reservas que éstos ponen a la doctrina kantiana. ¿Es posible conciliar las dos visiones de la metafísica del conocimiento aquí confrontadas? ¿Es totalmente asimilable el intelecto agente aristotélico con el "a priori" formal kantiano?

4. La antropología trascendental de Rahner

La interpretación marechaliana de la gnoseología clásica es recogida y ampliada por la antropología trascendental de Karl Rahner (1904-1984). En efecto, resulta bien conocido que el teólogo alemán recibió una formación escolástica fuertemente mediatizada por la filosofía de Maréchal. Ya en 1939 (sólo trece años después de la aparición de la obra del filósofo belga) Rahner publica el libro Espíritu en el mundo, en donde recoge su síntesis entre la teoría del conocimiento tomista y la kantiana. También para Rahner el intelecto agente es una condición de posibilidad del pensar, es decir, un a priori del sujeto: "En lo conocido intelectualmente es copercibido un elemento apriórico, que el espíritu comporta consigo (...), y éste es la condición de todo conocimiento objetivo (...). Este elemento a priori de todo conocimiento no es idea innata alguna, porque es sólo copercibido como condición de posibilidad de la aprehensión intelectual de lo sensiblemente dado, a saber, cuando ejerce una función «formal» con respecto al material de la sensibilidad". Adviértase cómo de manera explícita se separa de la concepción rosminiana, según la cual el intelecto agente es una idea innata, a través de la cual percibimos toda la realidad. Esta caracterización del intelecto agente parecería responder mejor a la concepción escolástica, como se manifiesta a la hora de explicar la metáfora de la luz aplicada al entendimiento agente: "Una de las imágenes más usadas para la descripción de la función del intellectus agens, es la representación de que los phantasmata son iluminados por el intellectus agens como lumen. ¿Qué quiere decir esta imagen? Si nos atenemos sencillamente a la imagen misma, se nos dice por de pronto que se trata de un hacer visible al phantasma por el intellectus agens. Ésta es, en general, la tarea de la luz con respecto al objeto iluminado por ella". Pero la propuesta rahneriana parece ir más lejos de la interpretación clásica cuando a continuación parece fundar la "visibilidad" exclusivamente en la conciencia y no en la realidad misma. En efecto, para el pensador alemán, "el «ser visible» es en nuestro caso, naturalmente, la conciencia". En esta sencilla afirmación parece condensarse el giro gnoseológico operado por la antropología trascendental de Rahner. Continuando con la analogía de la visión intelectual, la inteligibilidad parece descansar sólo en la espontaneidad de la conciencia y no en la inteligibilidad ontológica de la realidad. Por otro lado, la antropología trascendental de Rahner hace coincidir también la iluminación del intelecto agente con la conversio ad phantasmata del entendimiento agente. "Al concebir el acontecer de la abstractio en cuanto información del contenido sensiblemente dado por la luz del intellectus agens, incluye ya una conversio intellectus ad phantasma como aplicación de la luz a lo sensiblemente sabido. En tal proceso se cumple tanto la abstractio como la conversio, y con todo derecho pueden caracterizarse como illuminatio, bien, en primer término, la abstractio como tal, es decir, unida con el contenido sensible; bien en segundo lugar, la conversio ad phantasma, o sea, la unión de la forma apriórica con el contenido sensible". Comentando este texto, Fabro apunta que para Rahner tanto la abstracción como la conversión a las imágenes no son más que dos momentos de la autoaclaración del espíritu mediante la reditio completa del alma sobre sí misma, pero de esta manera desembocaremos en una gnoseología de corte inmanentista, como el mismo Fabro con estas palabras. "Si, como quiere el pensamiento moderno, el objeto del conocer es el acto de conciencia, la abstracción no puede consistir en tener conciencia del phantasma, ya que de éste el hombre tiene conciencia mediante la sensibilidad y no tiene necesidad de una nueva conciencialidad". "Por lo tanto, el acto de ser extra animam que para Sto. Tomás es el estímulo que lleva al entendimiento a «tomar conciencia de» (la realidad), en el tratamiento rahneriano se convierte en el acto de conciencia de sí misma".

Como hace ver Possenti, la noción de intencionalidad cognoscitiva, presente en toda la tradición aristotélica, parece olvidada en los planteamientos gnoseológicos rahrenianos. En efecto, en el planteamiento clásico, el conocimiento intelectual se encuentra intencionalmente "volcado" hacia lo conocido, es decir, la misma realidad. Pero sin intencionalidad cognoscitiva la conciencia se vuelve hacia sí misma. De esta manera, Rahner concibe la abstracción intelectual no como la aprehensión intencional de la realidad sino como una vuelta del sujeto sobre sí mismo. La interpretación apriórica del intelecto agente realizada por la antropología trascendental de Karl Rahner, se encuentra también presente en otros autores como De Petter, Coreth, Mertens y Verbeke. Estos autores llevan a cabo una particular exégesis de los textos tomistas lo que les lleva a concebir los primeros principios metafísicos no fundados en la realidad misma, sino inscritos en ella gracias a la actividad del intelecto agente debido a su carácter trascendental y a priori. Así por ejemplo, Verbeke de manera explícita afirma que según Santo Tomás el intelecto agente es capaz de "introducir" la inteligibilidad en los datos sensibles, y en última instancia, el que torna inteligible el mundo material. Pero si el mundo no está dotado de inteligibilidad propia, y si es el entendimiento agente la única causa de la inteligibilidad del mismo nos situamos bien lejos de la postura aristotélica.

5. Conclusiones

En 1852, Ernest Renan publicó su célebre tesis doctoral sobre el pensamiento de Averroes, en la deja constancia también de los paralelismos existentes entre las posturas aristotélicas y kantianas. "Al traducir a lenguaje moderno la teoría del entendimiento, expuesta en el libro III Del Alma , y desprendiéndola de las formas demasiado substanciales del estilo aristotélico, se llega a una teoría del conocimiento bastante análoga a la que desde hace medio siglo ha ganado el asentimiento de todos los espíritus filosóficos". "Pero este método de analogías —continúa Renan— es siempre peligroso. Los sistemas antiguos deben tomarse tales como son, y deben ser aceptados como curiosos productos del espíritu humano, sin que se deba tratar de interpretarlos con arreglo a las opiniones de la filosofía moderna".¿Hemos de renunciar a una lectura moderna de la doctrina del intelecto agente, siguiendo el consejo de Renan? ¿Resultan tan dispares las respuestas acerca del modo de conocer en el planteamiento clásico y en el kantiano? Si tenemos en cuenta que la gnoseología aristotélica y la kantiana son intentos por superar tanto la concepción empirista –que acaba reduciendo el conocimiento humano a la sensación– como al innatismo –ya sea en su versión platónica o cartesiana–, ambas concepciones muestran paralelismos válidos. Esta base común hace posible captar las semejanzas entre la gnoseología crítica de Kant y el realismo cognoscitivo de la tradición aristotélica. En mi opinión, si se pretende superar una gnoseología empirista debemos recuperar un teoría del conocimiento estructuralmente similar a la propuesta aristotélica del intelecto agente. Con esto no afirmo más que la necesidad de seguir abriendo nuevas perspectivas de estudio que nos ayuden a comprender mejor el problema de la prioridad del conocimiento intelectual.En este sentido, el intento por traducir en términos kantianos la gnoseología escolástica supone sin duda un esfuerzo especulativo para hacer más comprensible la oscura doctrina del intelecto agente. De esta manera puede ser legítimo afirmar que el intelecto agente es un "a priori" del conocimiento humano, porque todavía no cuenta con la base empírica que hace posible el concepto. Y consecuentemente, el entendimiento agente se

debe colocar del lado trascendental, previo a la experiencia sensible y condición de posibilidad del conocer humano. Es preciso, sin embargo, ahondar en estas aparentes coincidencias. Rosmini y Balmes advierten explícitamente que la propuesta kantiana pone el acento en el sujeto trascendental, pero se deja en entredicho la objetividad del conocer. Sin embargo, Maréchal, y sobre todo, Rahner no parecen marcar explícitamente las distancias con el planteamiento trascendental kantiano. El giro gnoseológico kantiano en favor de la conciencia parece ser plenamente asumido en esta última interpretación: nos encontramos, a mi modo de ver, frente a una lectura kantiana del entendimiento agente aristotélico. Pero hacer una lectura kantiana de Aristóteles ¿no es deformar al mismo Aristóteles? De la misma manera, se puede intentar hacer una lectura aristotélica de Kant, pero ¿no sería esto deformar la originalidad del planteamiento kantiano? Parece útil y necesario establecer paralelismos entre los planteamientos de estos dos filósofos, mostrando la perenne actualidad de los problemas gnoseológicos. No obstante, sería necesario no obviar sus profundas divergencias metafísicas y gnoseológicas: sólo así estaremos en condiciones de hacer justicia a cada uno uno de ellos, y, sobre todo, hacer justicia a la filosofía misma.

José Angel García CuadradoFacultad eclesiástica de FilosofíaUniversidad de Navarra31008 Pamplona (España)jagarcia@unav.es

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Stanford Enciclopedia of Philosophy

Bayesian Epistemology‘Bayesian epistemology’ became an epistemological movement in the 20th century, though its two main features can be traced back to the eponymous Reverend Thomas Bayes (c. 1701-61). Those two features are: (1) the introduction of a formal apparatus for inductive logic; (2) the introduction of a pragmatic self-defeat test (as illustrated by Dutch Book Arguments) for epistemic rationality as a way of extending the justification of the laws of deductive logic to include a justification for the laws of inductive logic. The formal apparatus itself has two main elements: the use of the laws of probability as coherence constraints on rational degrees of belief (or degrees of confidence) and the introduction of a rule of probabilistic inference, a rule or principle of conditionalization. Bayesian epistemology did not emerge as a philosophical program until the first formal axiomatizations of probability theory in the first half of the 20th century. One important application of Bayesian epistemology has been to the analysis of scientific practice in Bayesian Confirmation Theory. In addition, a major branch of statistics, Bayesian statistics, is based on Bayesian principles. In psychology, an important branch of learning theory, Bayesian learning theory, is also based on Bayesian principles. Finally, the idea of analyzing rational degrees of belief in terms of rational betting behavior led to the 20th century development of a new kind of decision theory, Bayesian decision theory, which is now the dominant theoretical model for the both the descriptive and normative analysis of decisions. The combination of its precise formal apparatus and its novel pragmatic self-defeat test for justification makes Bayesian epistemology one of the most important developments in epistemology in the 20th century, and one of the most promising avenues for further progress in epistemology in the 21st century.

1. Deductive and Probabilistic Coherence and Deductive and Probabilistic Rules of Inference 2. A Simple Principle of Conditionalization 3. Dutch Book Arguments 4. Bayes' Theorem and Bayesian Confirmation Theory 5. Potential Problems 6. Other Principles of Bayesian Epistemology Bibliography Other Internet Resources Related Entries

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1. Deductive and Probabilistic Coherence and Deductive and Probabilistic Rules of InferenceThere are two ways that the laws of deductive logic have been thought to provide rational constraints on belief: (1) Synchronically, the laws of deductive logic can be used to define the notion of deductive consistency and inconsistency. Deductive inconsistency so defined determines one kind of incoherence in belief, which I refer to as deductive incoherence. (2) Diachronically, the laws of deductive logic can constrain admissible changes in belief by providing the deductive rules of inference. For example, modus ponens is a deductive rule of inference that requires that one infer Q from premises P and P Q.

Bayesians propose additional standards of synchronic coherence -- standards of probabilistic coherence -- and additional rules of inference -- probabilistic rules of inference -- in both cases, to apply not to beliefs, but degrees of belief (degrees of confidence). For Bayesians, the most important standards of probabilistic coherence are the laws of probability. For more on the laws of probability, see the following supplementary article:

Supplement on Probability Laws For Bayesians, the most important probabilistic rule of inference is given by a principle of conditionalization. 2. A Simple Principle of ConditionalizationIf unconditional probabilities (e.g. P(S)) are taken as primitive, the conditional probability of S on T can be defined as follows: Conditional Probability:P(S/T) = P(S&T)/P(T). By itself, the definition of conditional probability is of little epistemological significance. It acquires epistemological significance only in conjunction with a further epistemological assumption: Simple Principle of Conditionalization:If one begins with initial or prior probabilities Pi, and one acquires new evidence which can be represented as becoming certain of an evidentiary statement E (assumed to state the totality of one's new evidence and to have initial probability greater than zero), then rationality requires that one systematically transform one's initial probabilities to generate final or posterior probabilities Pf by conditionalizing on E -- that is: Where S is any statement, Pf(S) = Pi(S/E).[1] In epistemological terms, this Simple Principle of Conditionalization requires that the effects of evidence on rational degrees be analyzed in two stages: The first is non-inferential. It is the change in the probability of the evidence statement E from Pi(E), assumed to be greater than zero and less than one, to Pf(E) = 1. The second is a probabilistic inference of conditionalizing on E from initial probabilities (e.g., Pi(S)) to final probabilities (e.g., Pf(S) = Pi(S/E)). Problems with the Simple Principle (to be discussed below) have led many Bayesians to qualify the Simple Principle by limiting its scope. In addition, some Bayesians follow Jeffrey in generalizing the Simple Principle to apply to cases in which one's new evidence is less than certain (also discussed below). What unifies Bayesian epistemology is a conviction that conditionalizing (perhaps of a generalized sort) is rationally required in some important contexts -- that is, that some sort of conditionalization principle is an important principle governing rational changes in degrees of belief.

3. Dutch Book ArgumentsMany arguments have been given for regarding the probability laws as coherence conditions on degrees of belief and for taking some principle of conditionalization to be a rule of probabilistic inference. The most distinctively Bayesian are those referred to as Dutch Book Arguments. Dutch Book Arguments represent the possibility of a new kind of justification for epistemological principles. A Dutch Book Argument relies on some descriptive or normative assumptions to connect degrees of belief with willingness to wager -- for example, a person with degree of belief p in sentence S is assumed to be willing to pay up to and including $p for a unit wager on S (i.e., a wager that pays $1 if S is true) and is willing to sell such a wager

for any price equal to or greater than $p (one is assumed to be equally willing to buy or sell such a wager when the price is exactly $p).[2] A Dutch Book is a combination of wagers which, on the basis of deductive logic alone, can be shown to entail a sure loss. A synchronic Dutch Book is a Dutch Book combination of wagers that one would accept all at the same time. A diachronic Dutch Book is a Dutch Book combination of wagers that one will be motivated to enter into at different times.

Ramsey and de Finetti first employed synchronic Dutch Book Arguments in support of the probability laws as standards of synchronic coherence for degrees of belief. The first diachronic Dutch Book Argument in support of a principle of conditionalization was reported by Teller, who credited David Lewis. The Lewis/Teller argument depends on a further descriptive or normative assumption about conditional probabilities due to de Finetti: An agent with conditional probability P(S/T) = p is assumed to be willing to pay any price up to and including $p for a unit wager on S conditional on T. (A unit wager on S conditional on T is one that is called off, with the purchase price returned to the purchaser, if T is not true. If T is true, the wager is not called off and the wager pays $1 if S is also true.) On this interpretation of conditional probabilities, Lewis, as reported by Teller, was able to show how to construct a diachronic Dutch Book against anyone who, on learning only that T, would predictably change his/her degree of belief in S to Pf(S) > Pi(S/T); and how to construct a diachronic Dutch Book against anyone who, on learning only that T, would predictably change his/her degree of belief in S to Pf(S) < Pi(S/T). For illustrations of the strategy of the Ramsey/de Finetti and the Lewis/Teller arguments, see the following supplementary article:

Supplement on Dutch Book Arguments There has been much discussion of exactly what it is that Dutch Book Arguments are supposed to show. On the literal-minded interpretation, their significance is that they show that those whose degrees of belief violate the probability laws or those whose probabilistic inferences predictably violate a principle of conditionalization are liable to enter into wagers on which they are sure to lose. There is very little to be said for the literal-minded interpretation, because there is no basis for claiming that rationality requires that one be willing to wager in accordance with the behavioral assumptions described above. An agent could simply refuse to accept Dutch Book combinations of wagers. A more plausible interpretation of Dutch Book Arguments is that they are to be understood hypothetically, as symptomatic of what has been termed pragmatic self-defeat. On this interpretation, Dutch Book Arguments are a kind of heuristic for determining when one's degrees of belief have the potential to be pragmatically self-defeating. The problem is not that one who violates the Bayesian constraints is likely to enter into a combination of wagers that constitute a Dutch Book, but that, on any reasonable way of translating one's degrees of belief into action, there is a potential for one's degrees of belief to motivate one to act in ways that make things worse than they might have been, when, as a matter of logic alone, it can be determined that alternative actions would have made things better (on one's own evaluations of better and worse).

Another way of understanding the problem of susceptibility to a Dutch Book is due to Ramsey: Someone who is susceptible to a Dutch Book evaluates identical bets differently based on how they are described. Putting it this way makes susceptibility to Dutch Books sound irrational. But this standard of rationality would make it irrational

not to recognize all the logical consequences of what one believes. This is the assumption of logical omniscience (discussed below).

If successful, Dutch Book Arguments would reduce the justification of the principles of Bayesian epistemology to two elements: (1) an account of the appropriate relationship between degrees of belief and choice; and (2) the laws of deductive logic. Because it would seem that the truth about the appropriate relationship between the degrees of belief and choice is independent of epistemology, Dutch Book Arguments hold out the potential of justifying the principles of Bayesian epistemology in a way that requires no other epistemological resources than the laws of deductive logic. For this reason, it makes sense to think of Dutch Book Arguments as indirect, pragmatic arguments for according the principles of Bayesian epistemology much the same epistemological status as the laws of deductive logic. Dutch Book Arguments are a truly distinctive contribution made by Bayesians to the methodology of epistemology.

It should also be mentioned that some Bayesians have defended their principles more directly, with non-pragmatic arguments. In addition to reporting Lewis's Dutch Book Argument, Teller offers a non-pragmatic defense of Conditionalization. There have been many proposed non-pragmatic defenses of the probability laws, the most compelling of which is due to Joyce. All such defenses, whether pragmatic or non-pragmatic, produce a puzzle for Bayesian epistemology: The principles of Bayesian epistemology are typically proposed as principles of inductive reasoning. But if the principles of Bayesian epistemology depend ultimately for their justification solely on the laws of deductive logic, what reason is there to think that they have any inductive content? That is to say, what reason is there to believe that they do anything more than extend the laws of deductive logic from beliefs to degrees of belief? It should be mentioned, however, that even if Bayesian epistemology only extended the laws of deductive logic to degrees of belief, that alone would represent an extremely important advance in epistemology.

4. Bayes' Theorem and Bayesian Confirmation TheoryThis section reviews some of the most important results in the Bayesian analysis of scientific practice -- Bayesian Confirmation Theory. It is assumed that all statements to be evaluated have prior probability greater than zero and less than one. Bayes' Theorem and a CorollaryBayes' Theorem is a straightforward consequence of the probability axioms and the definition of conditional probability:

Bayes' Theorem:P(S/T) = P(T/S) × P(S)/P(T) [where P(T) is assumed to be greater than zero] The epistemological significance of Bayes' Theorem is that it provides a straightforward corollary to the Simple Principle of Conditionalization. Where the final probability of a hypothesis H is generated by conditionalizing on evidence E, Bayes' Theorem provides a formula for the final probability of H in terms of the prior or initial likelihood of H on E (Pi(E/H)) and the prior or initial probabilities of H and E: Corollary of the Simple Principle of Conditionalization:Pf(H) = Pi(H/E) = Pi(E/H) × Pi(H)/Pi(E). Due to the influence of Bayesianism, likelihood is now a technical term of art in confirmation theory. As used in this technical sense, likelihoods can be very useful.

Often, when the conditional probability of H on E is in doubt, the likelihood of H on E can be computed from the theoretical assumptions of H.

Bayesian Confirmation TheoryA. Confirmation and disconfirmation. In Bayesian Confirmation Theory, it is said that evidence confirms (or would confirm) hypothesis H (to at least some degree) just in case the prior probability of H conditional on E is greater than the prior unconditional probability of H: Pi(H/E) > Pi(H). E disconfirms (or would disconfirm) H if the prior probability of H conditional on E is less than the prior unconditional probability of H. B. Confirmation and disconfirmation by entailment. Whenever a hypothesis H logically entails evidence E, E confirms H. This follows from the fact that to determine the truth of E is to rule out a possibility assumed to have non-zero prior probability that is incompatible with H -- the possibility that ~E. A corollary is that, where H entails E, ~E would disconfirm H, by reducing its probability to zero. The most influential model of explanation in science is the hypothetico-deductive model (e.g., Hempel). Thus, one of the most important sources of support for Bayesian Confirmation Theory is that it can explain the role of hypothetico-deductive explanation in confirmation.

C. Confirmation of logical equivalents. If two hypotheses H1 and H2 are logically equivalent, then evidence E will confirm both equally. This follows from the fact that logically equivalent statements always are assigned the same probability.

D. The confirmatory effect of surprising or diverse evidence. From the corollary above, it follows that whether E confirms (or disconfirms) H depends on whether E is more probable (or less probable) conditional on H than it is unconditionally -- that is, on whether:

(b1) P(E/H)/P(E) > 1. An intuitive way of understanding (b1) is to say that it states that E would be more expected (or less surprising) if it were known that H were true. So if E is surprising, but would not be surprising if we knew H were true, then E will significantly confirm H. Thus, Bayesians explain the tendency of surprising evidence to confirm hypotheses on which the evidence would be expected. Similarly, because it is reasonable to think that evidence E1 makes other evidence of the same kind much more probable, after E1 has been determined to be true, other evidence of the same kind E2 will generally not confirm hypothesis H as much as other diverse evidence E3, even if H is equally likely on both E2 and E3. The explanation is that where E1 makes E2 much more probable than E3 (Pi(E2/E1) >> Pi(E3/E1), there is less potential for the discovery that E2 is true to raise the probability of H than there is for the discovery that E3 is true to do so.

E. Relative confirmation and likelihood ratios. Often it is important to be able to compare the effect of evidence E on two competing hypotheses, Hj and Hk, without having also to consider its effect on other hypotheses that may not be so easy to formulate or to compare with Hj and Hk. From the first corollary above, the ratio of the final probabilities of Hj and Hk would be given by:

Ratio Formula:Pf(Hj)/Pf(Hk) = [Pi(E/Hj) × Pi(Hj)]/[Pi(E/Hk) × Pi(Hk)]

If the odds of Hj relative to Hk are defined as ratio of their probabilities, then from the Ratio Formula it follows that, in a case in which change in degrees of belief results from conditionalizing on E, the final odds (Pf(Hj)/Pf(Hk)) result from multiplying the initial odds (Pi(Hj)/Pi(Hk)) by the likelihood ratio (Pi(E/Hj)/Pi(E/Hk)). Thus, in pairwise comparisons of the odds of hypotheses, the likelihood ratio is the crucial determinant of the effect of the evidence on the odds. F. The typical differential effect of positive evidence and negative evidence. Hempel first pointed out that we typically expect the hypothesis that all ravens are black to be confirmed to some degree by the observation of a black raven, but not by the observation of a non-black, non-raven. Let H be the hypothesis that all ravens are black. Let E1 describe the observation of a non-black, non-raven. Let E2 describe the observation of a black raven. Bayesian Confirmation Theory actually holds that both E1 and E2 may provide some confirmation for H. Recall that E1 supports H just in case Pi(E1/H)/Pi(E1) > 1. It is plausible to think that this ratio is ever so slightly greater than one. On the other hand, E2 would seem to provide much greater confirmation to H, because, in this example, it would be expected that Pi(E2/H)/Pi(E2) >> Pi(E1/H)/Pi(E1).

These are only a sample of the results that have provided support for Bayesian Confirmation Theory as a theory of rational inference for science. For further examples, see Howson and Urbach. It should also be mentioned that an important branch of statistics, Bayesian statistics is based on the principles of Bayesian epistemology.

5. Potential ProblemsThis section reviews some of the most important potential problems for Bayesian Confirmation Theory and for Bayesian epistemology generally. No attempt is made to evaluate their seriousness here, though there is no generally agreed upon Bayesian solution to any of them. 5.1 Objections to the Probability Laws as Standards of Synchronic CoherenceA. The assumption of logical omniscience. The assumption that degrees of belief satisfy the probability laws implies omniscience about deductive logic, because the probability laws require that all deductive logical truths have probability one, all deductive inconsistencies have probability zero, and the probability of any conjunction of sentences be no greater than any of its deductive consequences. This seems to be an unrealistic standard for human beings. Hacking and Garber have made proposals to relax the assumption of logical omniscience. Because relaxing that assumption would block the derivation of almost all the important results in Bayesian epistemology, most Bayesians maintain the assumption of logical omniscience and treat it as an ideal to which human beings can only more or less approximate. B. The problem of the priors. Are there constraints on prior probabilities other than the probability laws? Consider Goodman's "new riddle of induction": In the past all observed emeralds have been green. Do those observations provide any more support for the generalization that all emeralds are green than they do for the generalization that all emeralds are grue (green if observed before now; blue if observed later); or do they provide any more support for the prediction that the next emerald observed will be green than for the prediction that the next emerald observed will be grue (i.e., blue)? This question divides Bayesians into two categories:

(a) Objective Bayesians (e.g., Rosenkrantz) hold that there are rational constraints on prior probabilities that require that observations support the green-generalization and the

green-prediction much more strongly than the grue-generalization and the grue-prediction. Objective Bayesians are the intellectual heirs of the advocates of a Principle of Indifference for probability. Rosenkrantz builds his account on the maximum entropy rule proposed by E.T. Jaynes. The difficulties in formulating an acceptable Principle of Indifference have led most Bayesians to abandon Objective Bayesianism. (b) Subjective Bayesians (e.g., de Finetti) do not believe that rationality alone places enough constraints on one's prior probabilities to make them objective. For Subjective Bayesians, it is up to our own free choice or to evolution or to socialization or some other non-rational process to determine one's prior probabilities. Rationality only requires that the prior probabilities satisfy relatively modest synchronic coherence conditions.

Subjective Bayesians believe that their position is not objectionably subjective, because of results (e.g., Doob or Gaifman and Snir) proving that even subjects beginning with very different prior probabilities will tend to converge in their final probabilities, given a suitably long series of shared observations. These convergence results are not completely reassuring, however, because they only apply to agents who already have significant agreement in their priors and they do not assure convergence in any reasonable amount of time. Also, they typically only guarantee convergence on the probability of predictions, not on the probability of theoretical hypotheses. For example, Carnap favored prior probabilities that would never raise above zero the probability of a generalization over a potentially infinite number of instances (e.g., that all crows are black), no matter how many observations of positive instances (e.g., black crows) one might make without finding any negative instances (i.e., non-black crows). In addition, the convergence results depend on the assumption that the only changes in probabilities that occur are those that are the non-inferential results of observation on evidential statements and those that result from conditionalization on such evidential statements. Because of the problem of the priors, it is an open question whether Bayesian Confirmation Theory has inductive content, or whether it merely translates the framework for rational belief provided by deductive logic into a corresponding framework for rational degrees of belief.

5.2 Objections to The Simple Principle of Conditionalization as a Rule of Inference, Especially as an Explanation of Theory Confirmation in ScienceA. The problem of uncertain evidence. The Simple Principle of Conditionalization requires that the acquisition of evidence be representable as changing one's degree of belief in a statement E to one -- that is, to certainty. But many philosophers would object to assigning probability of one to any contingent statement, even an evidential statement, because, for example, it is well-known that scientists sometimes give up previously accepted evidence. Jeffrey has proposed a generalization of the Principle of Conditionalization that yields that principle as a special case. Jeffrey's idea is that what is crucial about observation is not that it yields certainty, but that it generates a non-inferential change in the probability of an evidential statement E and its negation ~E (assumed to be the locus of all the non-inferential changes in probability) from initial probabilities between zero and one to Pf(E) and Pf(~E) = [1 Pf(E)]. Then on Jeffrey's account, after the observation, the rational degree of belief to place in an hypothesis H would be given by the following principle:

Principle of Jeffrey Conditionalization:

Pf(H) = Pi(H/E) × Pf(E) + Pi(H/~E) × Pf(~E) [where E and H are both assumed to have prior probabilities between zero and one] Counting in favor of Jeffrey's Principle is its theoretical elegance. Counting against it is the practical problem that it requires that one be able to completely specify the direct non-inferential effects of an observation, something it is doubtful that anyone has ever done. Skyrms has given it a Dutch Book defense.

B. The problem of old evidence. On a Bayesian account, the effect of evidence E in confirming (or disconfirming) a hypothesis is solely a function of the increase in probability that accrues to E when it is first determined to be true. This raises the following puzzle for Bayesian Confirmation Theory discussed extensively by Glymour: Suppose that E is an evidentiary statement that has been known for some time -- that is, that it is old evidence; and suppose that H is a scientific theory that has been under consideration for some time. One day it is discovered that H implies E. In scientific practice, the discovery that H implied E would typically be taken to provide some degree of confirmatory support for H. But Bayesian Confirmation Theory seems unable to explain how a previously known evidentiary statement E could provide any new support for H. For conditionalization to come into play, there must be a change in the probability of the evidence statement E. Where E is old evidence, there is no change in its probability. Some Bayesians who have tried to solve this problem (e.g., Garber) have typically tried to weaken the logical omniscience assumption to allow for the possibility of discovering logical relations (e.g., that H and suitable auxiliary assumptions imply E). As mentioned above, relaxing the logical omniscience assumption threatens to block the derivation of almost all of the important results in Bayesian epistemology, so there is no general agreement among Bayesians on how to solve this problem. Other Bayesians (e.g., Lange) employ the Bayesian formalism as a tool in the rational reconstruction of the evidentiary support for a scientific hypothesis, where it is irrelevant to the rational reconstruction whether the evidence was discovered before or after the theory was initially formulated.

C. The problem of rigid conditional probabilities. When one conditionalizes, one applies the initial conditional probabilities to determine final unconditional probabilities. Throughout, the conditional probabilities themselves do not change; they remain rigid. Examples of the Problem of Old Evidence are but one of a variety of cases in which it seems that it can be rational to change one's initial conditional probabilities. Thus, many Bayesians reject the Simple Principle of Conditionalization in favor of a qualified principle, limited to situations in which one does not change one's initial conditional probabilities. There is no generally accepted account of when it is rational to maintain rigid initial conditional probabilities and when it is not.

D. The problem of prediction vs. accommodation. Related to the problem of Old Evidence is the following potential problem: Consider two different scenarios. In the first, theory H was developed in part to accommodate (i.e., to imply) some previously known evidence E. In the second, theory H was developed at a time when E was not known. It was because E was derived as a prediction from H that a test was performed and E was found to be true. It seems that E's being true would provide a greater degree of confirmation for H if the truth of E had been predicted by H than if H had been developed to accommodate the truth of E. There is no general agreement among Bayesians about how to resolve this problem. Some (e.g., Horwich) argue that Bayesianism implies that there is no important difference between prediction and

accommodation, and try to defend that implication. Others (e.g., Maher) argue that there is a way to understand Bayesianism so as to explain why there is an important difference between prediction and accommodation.

E. The problem of new theories. Suppose that there is one theory H1 that is generally regarded as highly confirmed by the available evidence E. It is possible that simply the introduction of an alternative theory H2 can lead to an erosion of H1's support. It is plausible to think that Copernicus' introduction of the heliocentric hypothesis had this effect on the previously unchallenged Ptolemaic earth-centered astronomy. This sort of change cannot be explained by conditionalization. It is for this reason that many Bayesians prefer to focus on probability ratios of hypotheses (see the Ratio Formula above), rather than their absolute probability; but it is clear that the introduction of a new theory could also alter the probability ratio of two hypotheses -- for example, if it implied one of them as a special case.

6. Other Principles of Bayesian EpistemologyOther principles of Bayesian epistemology have been proposed, but none has garnered anywhere near a majority of support among Bayesians. The most important proposals are merely mentioned here. It is beyond the scope of this entry to discuss them in any detail. A. Other principles of synchronic coherence. Are the probability laws the only standards of synchronic coherence for degrees of belief? Van Fraassen has proposed an additional principle (Reflection or Special Reflection), which he now regards as a special case of an even more general principle (General Reflection).[3]

B. Other probabilistic rules of inference. There seem to be at least two different concepts of probability: the probability that is involved in degrees of belief (epistemic or subjective probability) and the probability that is involved in random events, such as the tossing of a coin (chance). De Finetti thought this was a mistake and that there was only one kind of probability, subjective probability. For Bayesians who believe in both kinds of probability, an important question is: What is (or should be) the relation between them? The answer can be found in the various proposals for principles of direct inference in the literature. Typically, principles of direct inference are proposed as principles for inferring subjective or epistemic probabilities from beliefs about objective chance (e.g., Pollock). Lewis reverses the direction of inference, and proposes to infer beliefs about objective chance from subjective or epistemic probabilities, via his (Reformulated) Principal Principle.[4]

C. Principles of rational acceptance. What is the relation between beliefs and degrees of belief? Jeffrey proposes to give up the notion of belief (at least for empirical statements) and make do with only degrees of belief. Other authors (e.g., Levi, Maher, Kaplan) propose principles of rational acceptance as part of accounts of when it is rational to accept a statement as true, not merely to regard it as probable.

BibliographyBayes, Thomas, "An Essay Towards Solving a Problem in the Doctrine of Chances", Philosophical Transactions of the Royal Society of London (1764) 53: 37-418, reprinted in E.S. Pearson and M.G. Kendall, eds., Studies in the History of Statistics and probability (London: Charles Griffin, 1970).

Carnap, Rudolf, Logical Foundations of Probability (Chicago: University of Chicago Press; 1950). Carnap, Rudolf, The Continuum of Inductive Methods (Chicago: University of Chicago Press; 1952). de Finetti, Bruno, "La Prevision: ses lois logiques, se sources subjectives" (Annales de l'Institut Henri Poincare 7 (1937): 1-68. Translated into English and reprinted in Kyburg and Smokler, Studies in Subjective Probability (Huntington, NY: Krieger; 1980). Doob, J.L., "What is a Martingale?", American Mathematical Monthly 78 (1971): 451-462. Earman, John, Bayes or Bust? A Critical Examination of Bayesian Confirmation Theory (Cambridge, MA: MIT Press; 1992). Gaifman, H., and Snir, M., "Probabilities over Rich Languages", Journal of Symbolic Logic 47 (1982): 495-548. Garber, Daniel, "Old Evidence and Logical Omniscience in Bayesian Confirmation Theory", in J. Earman, ed., Testing Scientific Theories, Midwest Studies in the Philosophy of Science, Vol. X (Minneapolis: University of Minnesota Press; 1983): 99-131. Goodman, Nelson, Fact, Fiction, and Forecast (Cambridge: Harvard University Press; 1983). Glymour, Clark, Theory and Evidence (Princeton: Princeton University Press; 1980). Hacking, Ian, "Slightly More Realistic Personal Probability", Philosophy of Science 34 (1967): 311-325. Hempel, Carl G., Aspects of Scientific Explanation (New York: Free Press; 1965). Horwich, Paul, Probability and Evidence (Cambridge: Cambridge University Press; 1982). Howson, Colin, and Peter Urbach, Scientific Reasoning: The Bayesian Approach, 2nd ed. (Chicago: Open Court; 1993). Jaynes, E.T., "Prior Probabilities", Institute of Electrical and Electronic Engineers Transactions on Systems Science and Cybernetics, SSC-4 (1968): 227-241. Jeffrey, Richard, The Logic of Decision, 2nd ed. (Chicago: University of Chicago Press; 1983). Jeffrey, Richard, Probability and the Art of Judgment (Cambridge: Cambridge University Press; 1992). Joyce, James M., "A Nonpragmatic Vindication of Probabilism", Philosophy of Science 65 (1998): 575-603. Joyce, James M., The Foundations of Causal Decision Theory (Cambridge: Cambridge University Press; 1999). Kaplan, Mark, Decision Theory as Philosophy (Cambridge: Cambridge University Press; 1996). Lange, Marc, "Calibration and the Epistemological Role of Bayesian Conditionalization", Journal of Philosophy 96 (1999): 294-324. Levi, Isaac, The Enterprise of Knowledge (Cambridge, Mass.: MIT Press; 1980) Levi, Isaac, The Fixation Of Belief And Its Undoing (Cambridge: Cambridge University Press; 1991). Lewis, David, "A Subjectivist's Guide to Objective Chance", in Richard C. Jeffrey, ed., Studies in Inductive Logic and Probability, vol. 2 (Berkeley: University of California Press; 1980): 263-293. Maher, Patrick, "Prediction, Accommodation, and the Logic of Discovery", PSA, vol. 1 (1988): 273-285. Maher, Patrick, Betting on Theories (Cambridge: Cambridge University Press; 1993).

Pollock, John L., Nomic Probability and the Foundations of Induction (Oxford: Oxford University Press; 1990). Popper, Karl, The Logic of Scientific Discovery, 3rd ed. (London: Hutchinson; 1968). Ramsey, Frank P., "Truth and Probability," in Richard B. Braithwaite (ed.), Foundations of Mathematics and Other Logical Essay (London: Routledge and Kegan Paul; Check on 1931 publication date), pp. 156-198. Réyni, A., "On a New Axiomatic Theory of Probability", Acta Mathematica Academiae Scientiarium Hungaricae 6 (1955): 285-385. Rosenkrantz, R.D., Foundations and Applications of Inductive Probability (Atascadero, CA: Ridgeview Publishing; 1981). Savage, Leonard, The Foundations of Statistics, 2nd ed. (New York: Dover; 1972). Skyrms, Brian, Pragmatics and Empiricism (New Haven: Yale University Press; 1984). Skyrms, Brian, TheDynamics of Rational Deliberation (Cambridge, Mass.: Harvard University Press; 1990). Teller, Paul, "Conditionalization, Observation, and Change of Preference", in W. Harper and C.A. Hooker, eds., Foundations of Probability Theory, Statistical Inference, and Statistical Theories of Science (Dordrecht: D. Reidel; 1976). Van Fraassen, Bas C., "Calibration: A Frequency Justification for Personal Probability", in R.S. Cohen and L. Laudan, eds., Physics, Philosophy, and Psychoanalysis: Essays in Honor of Adolf Grunbaum (Dordrecht: Reidel; 1983). Van Fraassen, Bas C., "Belief and the Will", Journal of Philosophy 81 (1984): 235-256. Van Fraassen, Bas C., "Belief and the Problem of Ulysses and the Sirens", Philosophical Studies 77 (1995): 7-37. Zynda, Lyle, "Old Evidence and New Theories", Philosophical Studies 77 (1995): 67-95. Other Internet Resources[Please contact the author with suggestions] Related EntriesBayes' Theorem | logic: inductive | probability, interpretations of AcknowledgementsIn the preparation of this article, I have benefited from comments from Marc Lange, Stephen Glaister, Laurence BonJour, and James Joyce.

Copyright © 2001 William Talbott wtalbott@u.washington.edu

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Epistemologia Brian Ellis THE NEW ESSENTIALISM AND THE SCIENTIFIC IMAGE OF MANKIND 1. INTRODUCTION There are two very different theories about how the laws of nature relate to the world. On the first of these, the world is made up of intrinsically passive objects obeying laws of nature which are externally imposed upon them. On this theory, the laws of nature are contingent, and things of the same kinds as those existing in this world might well exist in other

worlds where different laws of nature apply. On the second theory, the world consists ultimately of things belonging to natural kinds whose essential properties include all of their causal powers, capacities and propensities. In such a world, the fundamental things are essentially active and bound by their natures to exercise their powers. This second theory entails that the laws of nature are immanent in the world, and that the things in it could not possibly have existed in other worlds with different laws affecting their behaviour. The first of these two theories is currently the most widely accepted, as indeed it has been since at least the Seventeenth Century. The second is an essentialist viewpoint of a kind which has not been strongly advocated since classical times. There is, however, good reason now to take the essentialist viewpoint seriously. For we have reason to believe in the existence of strict natural kinds of both objects and processes, and therefore in things having essential natures — as the essentialist theory requires. We also have reason to believe that the essential properties of things, i.e. those properties in virtue of which they are things of the natural kinds they are, always include at least some causal powers, capacities or propensities which determine how things of these kinds are intrinsically disposed to behave. It is impossible in the space of a brief paper to defend the new essentialism adequately. Aspects of the thesis have been defended in a number of other places, and the new essentialist theory, which I call ‘scientific essentialism’ is the subject of a book-length study which I hope to publish shortly1. Here my aim is to consider the impact which the new essentialism must have on the scientific image of mankind, and to argue that the manifest image of ourselves is much more easily accommodated to the new essentialist theory than it is to the more traditional neo-mechanistic one. Specifically, I wish to argue that the image we have of ourselves as thinking, more or less rational beings, who are capable of acting according to our beliefs and considered desires, is one which requires a scientific image of ourselves as active beings, with causal powers to act in accordance with our considered wishes, and with meta-causal powers to change our priorities, if we should see fit to do so. The view that the mental processes which are involved in all such deliberations are really just physical processes involving only essentially passive objects behaving as the universal laws of God or Nature dictate lies uneasily with this self-image. Scientific essentialism can give a much better account of the processes involved in choosing to act in one way rather than another. 2. THE MANIFEST AND THE SCIENTIFIC IMAGES OF THE WORLD Wilfrid Sellars [1963] speaks of two very different images of reality. He calls them the ‘manifest’ and the ‘scientific’ images. The manifest image is the view of ourselves, the world, and of our place in it, which derives from common experience, and from critical reflection on such experience. The scientific image is the view of reality which derives from science, when its laws and theories are understood realistically. The two images

are not obviously compatible. The scientific image, as it is presented to us by scientific realists, is objective, but seemingly dead and impoverished; the other, the manifest image, is often held to be dependent somehow on us as observers (or thinkers, or language-users), but it is a rich image, inhabited by living creatures, and things with genuine causal powers. The scientific image of Seventeenth Century mechanism was of a passive world consisting entirely of atoms which, in themselves, were neither coloured nor colourless, hot nor cold, sweet nor bitter, nor any other perceptible quality. The atoms, of which all things were thought to be composed were supposed to be infinitely hard and impenetrable, but, apart from their impenetrability, they were thought to have only the mechanical properties of shape, size, and (sometimes) mass, and the capacity to move or change orientation when pushed. According to E.A. Burtt [1932], the mechanistic world was one that was ‘hard, cold, colourless, silent, and dead; a world of quantity, a world of mathematically computable motions in mechanical regularity’ (p. 237). The manifest image, by contrast, was not passive, but inhabited by things having real causal powers, and by living, thinking, experiencing, conscious beings whose actions were often intentional, and intended to shape the world around them to suit their purposes. The world of our experience could not, it seemed, be reduced to events occurring in the dead mechanistic world of science. The most common response of Seventeenth and Eighteenth Century philosophers to this problem was to divide the world into mental and physical components. Mental events were thought to be essentially different from physical events, to occur in different substances, and occupy different realms. Science was taken as providing a description of the physical world, but not of the world of our experience. We are ourselves not even in the scientific picture, they thought. The scientific account of reality would include descriptions of our bodies, perhaps, but it could not also include descriptions of our inner selves or of our experiences. Such dualism did not solve the problem. If the material universe consisted of one kind of substance (having the primary characteristics of matter in a mechanistic world), but the human mind was made of a different kind of substance (having the capacities for experiencing, thinking, deciding, willing, and so on), then what is the relationship between the two? How can physical events produce mental events (e.g. in perception), or mental events produce physical ones (e.g. in acts of will)? In which domain do the answers to these questions lie? Dualism thus created at least as many problems as it solved. It removed the need to provide a mechanistic theory of mind, but it provided no clue what an alternative theory would be like, or how its processes would be related to the mechanisms of the body. Dualism may not be acceptable, but the scientific image, as it is presented to us by scientific realists today is also unacceptable. It is so because it presents an essentially Humean view of causation, and has no natural place within it for many of those most human qualities and capacities which inform the manifest image we have of ourselves as

rational agents observing and responding to each other, and to the world around us. So, the big question is: how can these two very different images of reality be reconciled. Of all of the problems of philosophy, this is perhaps the most intractable. It cannot be solved just by focussing on the manifest image, and attempting to articulate it. Nor can it be solved by resolutely attending to the nature of scientific inquiry, and ignoring its relationship to ordinary human experience. The two images must somehow be brought together, so that each can be seen in relationship to the other for what it is. The scientific image is far too powerful to be dismissed as a fabrication, with no implications for our conception of ourselves. On the other hand, the particular scientific image which has dominated Anglo-American philosophy since the Eighteenth Century seems too bare and passive to yield even a satisfactory account of causation. And it is quite manifestly inadequate to provide a sound basis for understanding human experience. It will be argued here that the scientific image, as it has traditionally been portrayed by philosophers, is much more impoverished than it needs to be. For it represents what is still really an Eighteenth Century view of the world. It does this by portraying inanimate nature as intrinsically passive, and therefore as being prima facie incapable of acting, except under the influence of external forces2. To bring the two images closer together, the scientific image needs to be updated. Specifically, it has to be recognised that the natural world is not intrinsically passive, but essentially active and interactive. Scientific essentialism is a metaphysic in which this fact about nature is recognised as being fundamental. It is a metaphysic which promises to create a scientific image of the world which is very different from the Humean one which mostly dominates the thinking of scientific realists. The scientific essentialist’s image is of an active world in which things have intrinsic causal powers; it is not that of a passive world of the kind in which Hume, his mechanistic predecessors, and his many followers believed (and still believe). In an active world of the kind envisaged by scientific essentialists, many things have causal powers, and many things are therefore agents of one kind or another. So the power of agency is not something unique to human beings, or other living creatures. It is a pervasive feature of reality. This is not to say that human agency is not something rather special: it clearly is. On the other hand, it is not as alien to the essentialist’s view of the world as it is to the Humean one.

3. SCIENTIFIC ESSENTIALISM3 The fundamental thesis of scientific essentialism is that the world is structured into hierarchies of natural kinds4 of objects and processes. It is not an amorphous world on which we must somehow impose our own system of categories. There is a pre-existing grid of objective categories, and it is the aim of natural science to reveal and describe them. The distinctions between the chemical elements, for example, are real and absolute. There is no continuum of elementary chemical variety which we must arbitrarily divide somehow into chemical elements. The distinctions

between the elements were there for us to discover, and the sharp distinctions between them are guaranteed by the limited variety of quantum mechanically possible atomic nuclei. Many of the distinctions between kinds of physical and chemical processes are also real and absolute. There is no continuum of processes within which the process of b-emission occurs, and from which it must be arbitrarily distinguished. The world is just not like that. At a fundamental level, the processes that occur often allow real and absolute distinctions of kind to be made. Therefore, if there are natural kinds of objects or substances, there are also natural kinds of events and processes. Scientific essentialism is thus concerned with natural kinds which range over events or processes as well as with the more traditional sort which range only over objects or substances. The natural kinds of these two types evidently occur in natural hierarchies. At the apex of the hierarchies, there are two very general natural kinds. The most general natural kind in the category of objects or substances includes every other natural kind of object or substance that exists, or can exist, in our world. This is the global kind, for our world, in this category. The most general kind in the category of events is the global kind which includes every other natural kind of event or process which occurs, or can occur, in the world. Scientific essentialists argue that the most general laws of nature describe the essential properties of these global kinds, and therefore hold necessarily of all objects, or of all events and processes. The law of conservation of energy, for example, states that every event or process of this global kind is one that is intrinsically conservative of energy. Hence, any event which was not intrinsically conservative of energy could not be one of a kind that could occur in our world. The laws we think of as causal laws are generally more specific in their direct application. The laws of electromagnetism, for example, apply directly to all electromagnetic radiation, and hold necessarily of all such radiation. Therefore, if there is any radiation which is not propagated according to these laws, it cannot possibly be electromagnetic. A second fundamental tenet of scientific essentialism is its claim that the essential properties of the most fundamental kinds of things are not just the passive primary qualities of classical mechanism, but also include a number of causal powers, capacities and propensities — powers to act, and powers to interact5. In other words, the basic things in the world are essentially active and dynamic. They are not just passive objects obeying blindly the commands of God, as most Seventeenth and Eighteenth Century philosophers believed; but things which have their own internal dynamics, which are essential to their natures, and which are determinative of their behaviour. It is this second tenet of scientific essentialism which sets it apart most strongly from other theories about the nature of reality. The claim that the world is structured into hierarchies of natural kinds of objects, and so on, could, in principle, be accepted by philosophers who were otherwise sympathetic to mechanism. Things of different natural kinds, they might say, are just things made up of different basic ingredients, or of the same ingredients, but put together different ways.

But there is nothing in their natures, they would add, which requires that they should behave in one way rather than another. How they are disposed to behave, they would say, depends on what the laws of nature happen to be. Scientific essentialism rejects this claim. It denies that the things existing in the world are as passive as this claim makes them out to be. According to scientific essentialism, all things are essentially active and reactive. At the most basic level, what they are intrinsically disposed to do is what makes them the kinds of things they are. Things of given kinds must always be disposed to behave in certain kinds of ways, just by virtue of being things of these kinds. Their identities as members of these kinds depends on their being so disposed to act. If this thesis of scientific essentialism is correct, then the laws of nature are not contingent, as nearly everyone else supposes, but metaphysically necessary, and hence true in all possible worlds. That is, it must be metaphysically impossible for things, constituted as they are, to behave other than in accordance with the laws of nature. Even God (assuming Him to exist and be all powerful) couldn’t make them behave contrary to their natures. He might change their natures, perhaps, so that they might become, or be replaced by, different kinds of things. But there is no possible world in which things, constituted as they are, could behave any differently. For them to behave differently, they would have to be or become things of different kinds, or be made up of things of different kinds. 4. ESSENTIALISM AND THE LAWS OF NATURE With very few exceptions, modern philosophers of science have accepted that the laws of nature are somehow imposed upon the world. Religious people still think of them as the commands of God; the non-religious generally think that it is a kind of cosmic accident that the laws are what they are. The laws of nature happen inexplicably to be what they are, they would say, but they could very well have been otherwise. Things with mass happen to attract one another gravitationally, more or less as Newton’s laws say they do, but these very same things, they would say, constituted just as they are, might well have attracted each other in some other way, if the laws of nature had been different. For example, they might have attracted each other according to an inverse cube law, rather than an inverse square one. This paper is based on the scientific essentialist claim that the laws of nature are immanent in the world, and derive from the essential natures of the things it contains. They are, according to this viewpoint, not externally imposed upon the world, as the divine command theory of laws implies; nor are they just universal regularities which happen, as a matter of unexplained fact, to regulate the behaviour of things in the world (as Hume believed, and as most Anglo-American philosophers still believe). The laws derive from the essential natures of the natural kinds of things that exist. For example, according to the new essentialism, it is not just a nomological accident, or due to an arbitrary command of God, that hydrogen has the spectrum it has. It is part of what it is

for a substance to be hydrogen that it should have such a spectrum. A substance simply would not be hydrogen, if it were not naturally disposed to display such a spectrum in appropriate circumstances. To summarise: According to modern essentialism, the world consists ultimately of things belonging to natural kinds. The members of these kinds are distinguished by their essential properties and structures. These essential properties and structures constitute the kind essences of the members of these kinds. The kind essences of the most fundamental kinds of things, include various causal powers, capacities and propensities, i.e. properties which are essentially dispositional in nature, implying dispositions to act or react in various ways, depending on the circumstances. Traditionally, such properties have been thought to be ontologically dependent on underlying categorical (i.e. non-dispositional) properties, and on the laws of nature. According to the new essentialism, however, at least some of these dispositional properties are fundamental, and not dependent on any other properties. The relationship of dependence between the causal powers and the laws of nature is the other way around, scientific essentialists say, i.e. the laws depend on the properties, not the properties on the laws. If all this is right, then things belonging to natural kinds must be naturally disposed to behave as these properties dictate. Specifically, if P is a causal power which disposes its bearer to Ei in circumstances Ci, and P is an essential property of things of the kind K, then anything of the kind K must be disposed to Ei in circumstances Ci. Indeed, it is part of what it is for anything to be a thing of the kind K that it should be so disposed. For every such case, the following law holds: L1: For all x and i, necessarily, if x is a thing of the kind K, then x is naturally disposed to Ei in circumstances Ci. Note that the necessity operator falls within the scope of the universal quantifier, and therefore in de re position. It is legitimate, therefore, to instantiate L1 to L2: Necessarily, if a is a thing of the kind K, then a is naturally disposed to Ei in circumstances Ci. Note also that if the individual essence of a thing includes its kind essence6, as many are inclined to say it does, then, if we are in a position to know that a is a thing of the kind K, we may detach and conclude that: Necessarily, a is naturally disposed to Ei in circumstances Ci. The essentialist theory, according to which things are necessarily disposed to act according to their natures, is not one which has been widely accepted in modern times. One has to go all the way back to Aristotle to find a truly notable defender of such a position. Yet, essentialism is precisely the sort of theory that one would expect any modern scientific realist to accept. For a realist would now be hard pressed to make much sense of the passive, and intrinsically inert, world on which the laws of nature are supposed to operate. The world, according to modern science, seems not to be innately passive, as mechanism requires, and modern Humeans presuppose, but fundamentally active and reactive. It is certainly not a world of things having only the attributes

of extension and impenetrability, as Descartes’ and Locke’s worlds were. Rather, it is a dynamic world consisting of more or less transient objects which are constantly interacting with each other. Moreover, the real defining characteristics of the most fundamental kinds of things that we know about, e.g. things like protons and electrons, would all appear to lie in their laws of interaction. Things of these kinds would appear to have no real defining characteristics at all apart from their causal roles. A proton, for example, might be defined (by way of real definition) as any particle which behaves as protons do. For no proton could possibly fail to behave in these ways, and no particle other than a proton could possibly imitate this behaviour. Its identity, qua proton, might thus be defined by its causal role. Similarly, one might say that an electron is, by real definition, any particle for which the laws of interaction are precisely those of electrons. Nothing other than an electron could possibly behave in such a way, and whatever does behave in this way has to be an electron. Again, a photon might really be defined as being a quantum of electromagnetic energy which behaves as all such quanta must. The kind identities of at least some of these more or less fundamental things in the world would thus appear to depend simply on their kind classifications and their distinctive causal roles. Whether this is so or not, does not matter much here. But it is at least highly implausible to suppose that the kind identities of these things are independent of their causal roles, as Humeanism implies they must be. If this speculation is right, then the laws concerning the behaviour of protons, and their interactions, cannot be just accidental, i.e. laws which could well have been otherwise. On the contrary, it is essential to the nature of a proton that it should be disposed to interact with things of various kinds precisely as it does. The proton’s causal powers, capacities and propensities, therefore, are, on this conception, not just amongst the accidental properties of protons, which depend on what the laws of nature happen to be, but amongst their essential properties, without which there would be no protons, and which protons could not lose without ceasing to exist. The traditional view that the laws of particle physics are imposed on intrinsically passive things which have kind-identities which are independent of the laws of their behaviour is thus implausible from the point of view of modern science. Essentialism is a much more plausible position to take. 5. CASUAL POWERS AND AGENCY Most philosophers today believe that the question of what causes what ultimately depends on what universal regularities hold. In Hume’s original theory, A is said to be the cause of B, if and only if, A precedes B, A is contiguous (both spatially and temporally) with B, and events of the kind A are regularly followed by events of the kind B. This theory is called the ‘regularity theory’ of causation. On Hume’s original theory, there are no genuine causal powers. An effect is not something which is somehow necessitated or brought about by its cause; it is just an event of a kind which happens to follow with universal regularity on events of the kind to which the cause belongs. Those who postulate that there are causal powers inherent in

objects which are displayed in causal processes are accused of trading in obscurities. According to Hume, there are no such things as causal powers, and causes do not necessitate their effects. Hume’s theory thus creates a problem for anyone who wishes to account for human agency. If Hume is right, then our conscious decision-making processes, and the actions which we say stem from them, must all be understood in terms of regularities, constant conjunctions, and the like, concerning which we, as conscious beings, can be nothing other than introspective spectators. But this is clearly not how they are in the manifest image we have of ourselves. We do not see ourselves as being in such a passive role. Rather, we see ourselves as acting, and doing things for reasons. We see our processes of deliberation as ones which are thoroughly under our control, and which we can continue, suspend, or eventually act upon. Acceptance of a Humean theory of causation thus makes it very difficult for anyone even to suggest a plausible theory of human agency. More recent accounts of causation which belong to the Humean tradition are not, of course, all the same as Hume’s. But most modern theories of causation which depend on counterfactual analyses, are not really very different from Hume’s. They are all agreed that a case of causation is ultimately just an instance of a universal generalisation. They disagree with each other mainly about the nature and status of this generalisation. But more importantly, from our point of view, they all cast the agent into the role of spectator to his or her own decision-making processes. Scientific essentialism turns all this on its head. For a scientific essentialist, all effects are displays of causal powers, or due indirectly to such displays, (as is the darkening of the room when the blinds are pulled). Effects are not just events which happen to follow the triggering of causal powers; they are (or are consequences of) their manifestations. If the mousetrap is not set off by the taking of the cheese, then presumably the disturbance was not sufficient to release the causal power latent in the spring. Unless there are extraordinary defeating circumstances, there can be no question of the catch being released and the mousetrap not snapping shut. Such an unlikely event could only occur if something were to intervene to prevent the mousetrap snapping shut. In the absence of any such defeaters, the mouse will be a dead mouse. The most elementary kinds of things all have fixed causal powers, i.e. their dispositional properties are all fixed by their essential natures. A copper atom, for example, has the same dispositional properties wherever or whenever it might occur. The same is true of a proton or an electron. They are things which belong to what might be termed ‘fixed natural kinds’. Their distinguishing feature is that you cannot change any of their dispositional properties. They do what things of these kinds always do, and you cannot teach them any new tricks. There can be no question of a copper atom, for example, being disposed to behave in one way at one time, but in a different way at another time. Nothing with such variable powers could possibly be a copper atom. For fixed natural kinds there are universal laws of action. These laws are

the causal laws. According to the new essentialism, all such laws are metaphysically necessary. They are metaphysically necessary, because things of these kinds have all of their dispositional properties essentially, and therefore could not possibly behave in ways other than as these properties dictate. The laws of chemical combination, for example, are causal laws which are necessary in this sense, as are the laws governing the behaviour of the fundamental particles. Things of these kinds must be disposed to behave as they do, because their identities as things of these kinds depend on their being so disposed. As we ascend to more complex structures, we find that things which plausibly still belong to natural kinds have more variable dispositional properties. A piece of iron, for example, is plausibly a member of a natural kind, the members of which are all essentially crystalline structures of metallic iron. But pieces of iron can become fatigued, and hence brittle, or they may become magnetised, and hence acquire a capacity to attract other pieces of iron, generate electric currents, and so on. So pieces of iron may gain or lose causal powers, depending on their histories or circumstances. Such changes in the causal powers of a thing do not normally add up to a change of essential nature. For the essential nature of a thing belonging to a natural kind is just the core set of its causal powers, capacities, structures, and so on, in virtue of which it is a member of the kind. Any intrinsic properties or structures which a thing may either gain or lose while yet remaining a member of the kind are properties or structures which it has only accidentally. At the next stage of organisational complexity, it seems that things may not only acquire or lose dispositional properties, accidentally, as it were, they may also gain or lose them by the exercise of higher powers of control, i.e. by the exercise of meta-powers. How meta-powers arise in the first place, I am not able to say. But that such powers exist seems evident enough from our own case. When someone acts to do something, they display a certain, perhaps very temporary, disposition. In at least some cases, this disposition results from an internal process of deliberation, a process which always involves the exercise of meta-powers. A deliberate action is not just an event of a kind which happens regularly to follow when intentional states of mind of a certain kind come into being. It is something that is done by the agent as a result of an intentional state of mind which is itself brought about by the agent, viz. by deliberation. Thus, it seems that human beings not only have variable dispositional properties, as most complex systems have, but also meta-powers, i.e. powers to change dispositional properties. Other animals, no doubt, have similar meta-powers, but that such powers exist, and are exercised, seems quite evident from our own case. We exercise such meta-powers whenever we deliberate about what to do, and we call any action which may result from this process a deliberate act of will. Scientific essentialism thus promises to reshape the scientific image of man. It promises to do so in a way which will bring the scientific and manifest images of ourselves closer together. For it deals with one aspect of the apparent conflict between them by providing a scientific image of human agency, an image which bears enough resemblance to its manifest

counterpart for it to be taken seriously as telling us what human agency really is. If scientific essentialism is accepted, then human agency could be accepted as the manifest image of actions brought about by people exercising their meta-causal powers, i.e. their powers of control. But what of consciousness, thoughts, beliefs, desires, and the other mental phenomena, which have traditionally been seen by scientific realists as problematic? My hypothesis is that these are all manifestations of aspects of things referred to in the kind of dynamic scientific image of man which the essentialist perspective generates. If this is so, then the problem for science is to identify the neuro-physiological processes or structures which are our thoughts, beliefs, desires and so on. Many years ago, J.J.C. Smart and U.T. Place made the philosophically bold claim that sensations are brain processes of certain kinds. I think that this claim was correct. But it is far less plausible to suppose that thinking, believing, desiring, and consciousness itself, can be identified with brain processes, if the brain processes of which they are supposed to be manifestations are just regularities in the behaviour of brain tissues which are essentially inert or passive. For a Humean, the problem of identifying neuro-physiological bases for passive things like sensations, the having of which would seem to require no action on our part (other than keeping our eyes open, and things like that), is not acute. The problem for Humeans is much greater, however, if they are seeking to identify the neuro-physiological bases for those mental activities which appear in the manifest image to be more or less under our control. It is even more acute for consciousness itself, which is germane to all human experience. If human agency is, as I would suppose, the exercising of our meta-powers to alter our own dispositions to act in one way rather than another, then it follows that we must be able to monitor our mental processes, including our thinking, believing, desiring, and so on. That is, we must have a kind of second-order or meta-perception, or ability to know directly by experience something of what is going on in our own heads when we are engaged in any of these activities. The neuro-physiological basis for this meta-perception must be something like a meta-level neuro-physiological process which scans the first-order processes involved in our various mental activities, including, it seems the activity of scanning. Consciousness, I would think, is such a meta-level scanning process. Department of History and Philosophy of Science The University of Melbourne, Victoria (Australia) NOTES 1 The book is Scientific Essentialism. The papers referred to include Ellis [1996, 1998, 1999a, 1999b, 1999c, and forthcoming], Bigelow, Ellis and Lierse [1992], and Ellis and Lierse [1994]. 2 Internal forces are really just external forces acting between the parts of things. 3 For a summary of some of the main theses of scientific essentialism, see

Appendix A. 4 For an explication of the concept of natural kind that is used in this paper, see Appendix B. 5 David Armstrong [1999] argues that such intrinsic causal powers are Meinongian properties, and thus objectionable. In principle, he says, there could be causal powers which happen never to be exercised. If such properties have no categorical bases, as I would allow is possible, then he says, such powers can be defined only by relationships between non-existent objects, i.e. between the kind of circumstances which would trigger them and the kind of display which would then result. For my reply, see Ellis [1999c]. 6 However, this is a controversial thesis, which would be endorsed by those whom I call strong essentialists. John Bigelow [1999], for one, has urged me to accept the stronger theory. For reasons given in my reply to Bigelow (Ellis [1999b]), I am inclined to reject it. To elaborate on these reasons, it is plausible to say that an atom of Uranium might lose a nuclear electron to become an atom of Neptunium, and hence something of an essentially different kind. For the purposes of this paper, nothing much hinges on whether we allow that this is possible. My inclination, is to allow that things can sometimes undergo changes of kind-identity, provided that the processes by which they do are natural ones. The process by which a Uranium atom decays to become an atom of Neptunium is b-emission, which is, of course, a natural process. There is no objection in principle, therefore, to allowing that such a change could take place. That the atom remains the same atom after b-emission has occurred is a trickier question. But since individual identity depends more on spatiotemporal and causal history than on intrinsic causal powers or internal constitution, it seems plausible to allow that the atom does indeed survive the change. REFERENCES D.M. Armstrong [1999], "Reply to Ellis", in Causation and Laws of Nature, H. Sankey (ed.), Kluwer Academic Publishers, Dordrecht, 1999, pp. 43-48.

D.M. Armstrong [forthcoming], "The Causal Theory of Properties: Shoemaker, Ellis and Others", Philosophical Studies. J.C. Bigelow [1999], "Scientific Ellisianism", in Causation and Laws of Nature, H. Sankey (ed.), Kluwer Academic Publishers, Dordrecht, 1999, pp. 56-76. J.C. Bigelow, B.D. Ellis and C. Lierse [1992], "The World as One of a Kind: Natural Necessity and Laws of Nature", British Journal for the Philosophy of Science 43 (1992), pp. 371-388. E.A. Burtt [1932], Metaphysical Foundations of Modern Science, Routledge and Kegan Paul, London, 19322. B.D. Ellis [1996], "Natural Kinds and Natural Kind Reasoning", in Natural Kinds, Laws of Nature and Scientific Methodology, P. Riggs (ed.), Kluwer Academic Publishers, Dordrecht, 1996, pp. 11-28. B.D. Ellis [1998], "An Essentialist Perspective on the Problem of Induction", Principia 2 (1998), pp. 103-124.

B.D. Ellis [1999a], "Causal Powers and Laws of Nature", in Causation and Laws of Nature, H. Sankey (ed.), Kluwer Academic Publishers, Dordrecht, 1999, pp. 21-42. B.D. Ellis [1999b], "Bigelow’s Worries about Scientific Essentialism", in Causation and Laws of Nature, H. Sankey (ed.), Kluwer Academic Publishers, Dordrecht, 1999, pp.77-97. B.D. Ellis [1999c], "Response to David Armstrong", in H. Sankey (ed.), Causation and Laws of Nature, Kluwer Academic Publishers, Dordrecht, 1999, pp. 49-55. B.D. Ellis [forthcoming], "Causal Laws and Singular Causation", Journal of Philosophy and Phenomenological Research. B.D. Ellis and C.E. Lierse [1994], "Dispositional Essentialism", Autralasian Journal of Philosophy 72 (1994), pp. 27-45. W. Sellars [1963], Science, Perception and Reality, Routledge and Kegan Paul, London, 1963, Ch. 1, pp. 1-40. Appendix A SOME THESES OF SCIENTIFIC ESSENTIALISM Scientific essentialism challenges orthodoxy in philosophy in a number of ways. As well as holding that matter is essentially passive, orthodox philosophers of science generally subscribe to the following theses: (a) that causal relations hold between logically independent events, (b) that the laws of nature are behavioural regularities of some kind which could, in principle, be found to exist in any field of inquiry, (c) that the laws of nature are contingent, (d) that the identities of objects are independent of the laws of nature, and (e) that the dispositional properties of things are not genuinely occurrent properties, which would have to be the same in all possible worlds, but somewhat phoney world-bound properties which depend on what the laws of nature happen to be. Against these theses, scientific essentialists would argue that nature is active, not passive, and that: (a) causal relations are relations between events in causal processes. If an event of a natural kind which would activate a given causal power in a certain way occurs, then an event of a natural kind which would then be an appropriate display that power must also occur (even though the effect may sometimes be masked by other effects). (b) the laws of nature are not just behavioural regularities, although they imply the existence of underlying patterns of behaviour, but descriptions of natural kinds of processes arising from the intrinsic properties of things belonging to natural kinds. There are, accordingly, no laws of nature in fields such as sociology or economics. (c) the laws of nature are not contingent, but metaphysically necessary The same things in the states in which they currently exist would have to have the same behavioural dispositions in any world in which they might exist. (d) the identities of objects are not independent of the laws of nature. If the laws of nature were different, the things existing in the world

would have to be different. (e) there are natural dispositional properties which are genuinely occurrent, and which therefore act in the same ways in all possible worlds. These include the causal powers of the most fundamental kinds of things; so that things of these same kinds, existing in any other world, would have to be disposed to behave in just the same ways. Appendix B THE PROPERTIES OF NATURAL KINDS 1. The distinctions between natural kinds depend on real and absolute differences. They do not depend on how we may find it useful, convenient or natural to classify them. Membership of a natural kind is thus decided by nature, not by us; and the question of whether something is or is not a member of a given natural kind can never be settled just by fiat or arbitration. This question can only be settled by discovering whether what is to be classified has the jointly distinctive (essential) properties or structure of the kind in question. It follows that the identity of a natural kind can never be dependent only on our interests, psychologies, perceptual apparatus, languages, practices or choices. If the identity of a kind depended on any of these things, then it might well be a kind of our own making, not one that exists in the world prior to our knowledge, perception or description of it. 2. Natural kinds are categorically distinct from each other. They are ontologically grounded as kinds, and exist as kinds independently of our conventions. Hence, where we are dealing with natural kinds, there cannot be any gradual merging of one kind into another, so that it becomes indeterminate to which kind a thing belongs. If there were any such merging, we should have to draw a line somewhere if we wished to make a distinction. But if we have to draw a line anywhere, then it becomes our distinction, not nature’s. Natural kinds must therefore be ontologically distinguishable from each other. 3. The distinctions between natural kinds are based on intrinsic (internal) differences. That is, the members of two different natural kinds do not differ only extrinsically (i.e. externally), depending on how things in the world happen to be arranged, or happen to be related to one another. If a thing’s membership of a natural kind were to depend on its relations to other things, for example, then its membership of the kind would be an accidental matter. It would be a relationship which depended on its accidental circumstances. Therefore, if there are any natural kinds in the world, they must exist as kinds independently of any such extrinsic relations, and their identities must be dependent only on the intrinsic natures of their members, not what their extrinsic relations to other things happen to be. To illustrate: it might be the case that the only gold in the universe is to be found on earth. But the natural kind distinction between gold and other substances does not depend at all on this fact. A substance could obviously be gold, but not located on earth. For a substance to be gold, it must be constituted as gold. It must have those intrinsic properties which make it gold. Likewise, for a process to be meiosis, it must be

constituted as meiosis, and involve the same kinds of substances changing in the same kinds of ways. 4. If two members of a given natural kind differ intrinsically from each other, and these intrinsic differences are not ones that can be either acquired or lost by members of the kind, then they must be members of different species of the kind. This is the speciation requirement. The isotopes of uranium, U235 and U238, differ intrinsically from each other. However, they both have the essential nuclear and electron structures of uranium, and are therefore species of uranium. Electromagnetic radiation of frequency 2000 differs intrinsically from electromagnetic radiation of frequency 3000. However, electromagnetic radiation of either frequency is propagated according to Maxwell’s equations, and both are species of electromagnetic radiation. 5. Natural kinds belong in hierarchies. If anything belongs to two different natural kinds, these natural kinds must both be species of some common genus. In other words, the memberships of two distinct natural kinds cannot overlap, so that each includes some, but not all, of the other, unless there is some broader genus which includes both kinds as species. The requirement is satisfied trivially if one of the two kinds is a species of the other. This is a feature of hierarchical structures generally. 6. Natural kinds are distinguished from other sorts of things by their associations with essential properties. If what makes an object or process one of a certain kind depends only on its intrinsic nature, then any object or process which has this nature must be one of this kind. The set of properties or structures in virtue of which a thing is something of the kind it is constitutes its kind essence. Brian Ellis IL NUOVO ESSENZIALISMO E L'IMMAGINE SCIENTIFICA DELL'UOMO Riassunto Vi sono due teorie molto diverse circa il modo in cui le leggi di natura sono correlate al mondo. Secondo la prima, il mondo è composto di oggetti intrinsecamente passivi, i quali obbediscono a leggi naturali che vengono imposte ad essi dall’esterno. Questa teoria afferma che le leggi di natura sono contingenti, e che le stesse cose esistenti nel nostro mondo potrebbero esistere in mondi con leggi naturali differenti. La seconda teoria invece sostiene che il mondo consiste di cose appartenenti a generi naturali le cui proprietà essenziali includono la totalità dei loro poteri, capacità e propensioni causali. In un simile mondo, i componenti fondamentali sono essenzialmente attivi e costretti dalla loro stessa natura ad esercitare i loro poteri. La seconda teoria ha caratteri essenzialisti, il che significa che le leggi di natura sono immanenti alla realtà, e che le cose in essa contenute non potrebbero esistere in altri mondi dotati di leggi naturali differenti. Nell’articolo si sostiene che, malgrado il suo essenzialismo e l’apparente rigidità, la seconda teoria produce una spiegazione dell’azione umana che risulta plausibile sia da ogni punto di vista.

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