REFERENCES Dillon, M.C.1997. Merleau-Ponty'sOntology.Evanston: NorthwesternUniver- sity Press. Einstein, Albert.1961.Relativity.TranslatedbyRobert W. Lawson. NewYork: Wings Books. . 1982. Ideas and Opinions. New York:Crown Publishers. Hass,Lawrence.1999."SenseandAlterity:RereadingMerleau-Ponty's ReversibilityThesis."InMerleau-Ponty,Interiority andExteriority,Psychic LifeandtheWorld(pp. 91-106),editedby DorotheaOlkowskiandJames Moreley. Albany:State University ofNew YorkPress. Merleau-Ponty, Maurice. 1962. The Phenomenology of Perception. Translated by Colin Smith. London: Routledge & KeganPaul. . 1964. "EyeandMind."InThePrimacyofPerception.Translatedby James M. Edie. Evanston, IL:NorthwesternUniversityPress. . 1968.TheVisibleandtheInvisible.Translatedby AlphonsoLingis. Evanston, IL:Northwestern University Press. . 1970. Themes Fromthe Lectures at theCollege deFrance,1952-1960. Translated byJohn OINeill. ~va'nston,IL:Northwestern University Press. Plato. 1971. Timaeus. Translated byBenjamin Jowett. In The Complete Dialogues ofPlato. Edited by Edith Hamilton and Huntington Cairns. Princeton: Prince- ton University Press. Yount,Mark."TwoReversibilities:Merleau-PontyandDerrida."InMerleau- Ponty,Hermeneutics andPost-Modernism (pp. 21 3-226),editedbyThomas Busch and Shaun Gallagher. Albany: State UniversityofNew YorkPress. JAMES J . GIBSON' S ECOLOGICAL APPROACH PERCEIVINGWHAT EXISTS WILLIAMM.MACE ENVIRONMENTALPHILOSOPHY ANDEPISTEMOLOGY The purpose ofthis paper is t o help an audience attracted to environ- mental philosophyget to the core ofGibson'ssysteminacompact form and t o appreciate the necessityfor an account ofthe environmentin epis- temology.I hopet o show thatGibson'sisaconsistentandscientifically progressiveaccountofknowingthatgivestheenvironment itsdueand thatthisisnotasimplematteroffiatbutacalltoextendedscientific investigation. I want to stress that Gibson'swork is scientificallyprogres- sive in the sense that it has consistentlyopened new avenues for research. Ifone could beassured tomorrow that Gibson was correct and his critics wrong,theecologicalpsychologyenterprisewouldnothavetobeshut downwithnothingleftt odo. Thegoaloftheenterprise,certainlyfor Gibson, was not t o be declared a winner but to open doors for discovery. BecauseGibson has developedatheory ofperceivingthe environment,it wouldbeworthexploringasanimportanttopicforenvironmental philosophers covering a wide range ofissues. It offers an intriguing, envi- ronmentallybased,groundingforepistemology;itofferswaystodeal IndianUniversity PressAllrights ofreproductioninany form reserved. Directallcorrespondenceto: Journals Manager, Indiana University Press, 601 N. Morton St., Bloomington, IN47404 USAiuporder@indiana.edu withpractical issues within"purescience";and it is open to reorganizing waysto conceptualize problemsbeyondepistemology. Gibsondevelopedarichlyarticulatedsystem that grew steadily over a periodof 50 years,1929 to1979, whichhe devotedto "puzzlingover" the"perplexities"ofvision(1979,xiii).FromGibson'sstandpoint, knowledgebegins withperception,and perceptionis perceivingthe envi- ronment. The environment, for Gibson, is at least as essentialas the brain to the existenceand exercise 01 "themind." Asan empiricist,knowledgeisbasedon perceptionforGibson.But perception,at root,turnsout to beperceptionofthe environment. Enti- ties like sense data and representationsbecome "afterthe fact" curiosities forGibson,andhavenoroletoplayinthefoundationsofperceptual experience and, a fortiori, knowledge.IfGibsoniscorrect, thenscientific accountsofperceptionmustconvergeonenvironmentalperception.A philosopherwhose primary focus is epistemology, and who works within Gibson'ssystem,wouldperforcebean environmentalphilosopher-not (first) becauseof aspecialconcern fortheenvironment,butbecausean adequate appreciation of relevant facts requires it. Of great importance to environmental philosophersisthat Gibson not onlyprovidesan account ofperceivinggroundedinaccesstoenvironmentalproperties,buthe establishesabasisforperceivingthisparticularworldasaspecific arrangement ofsurfaces. The worldweperceive, according to Gibson, is a connected, public worldthat weshare. Itis,again, the world,the logi- cal individual worldand not an abstraction. This is not an account ofthe experienceofabstractshapes, distances,andmotions.Itisasystemin whichtravelers can visit the pyramids andinwhichI cantrip overyour garbage. Is thereasymmetric directionofinfluence? Just as acommitment to understanding knowledgescientificallyand philosophicallycanleadone to focal considerationsofthe environment,couldadeep concernfor the environment as a valuelead to the serious study of perceptionand, more broadly,epistemology? It seems entirely plausible.Gibson'sis a"yinand yang"system ofscientific complementaritiesbeginningwithanimaland environmentandextendingtoknowledgeandvalue(in hisconceptof affordance).In each complementarity, the terms are differentiablebut not entirelyindependent.Animalsandtheirenvironmentsare differententi- tiesandshouldnotbeconfusedwithoneanother,buttheyalsoareso mutuallydependent thatoneshouldnotimagineathoroughaccount of one without the other. In like manner, objects and value(first through use) are not independently comprehensible inGibson'ssystem. This is a theme worthyofcarefulexamination ofdetailed examples. Iam not doing that inthispaper,buthopethat enoughoftheflavorofGibson'sworkwill come throughto allow a readert o understandhow one might be steered to epistemology from an initial concern with environmentand valuesand vice versa. Gibson'ssystemisnotsimplynewanswersto oldquestionsornew spins on old views. Questions and phenomena throughout psychology get repackaged.Themostimmediateillustrationismemory.AsIshall describe later,acoreGibsonianinsightisthat during change,not every- thingchanges. Some thingsstay thesame. Theyareinvariant.He noted that surface patterns ofthe environment that go out ofsight as one scans an environment in one direction, come backinto sight upon reversing the scan pattern. The surfaces can be seen to have a continuedexistence even ifnotseenallat the samemoment.Ifthepatternofan existingsurface canbeseenovertimethisway,asaunit,thenperceivingextendsover time.Put another way,one canseparate out the timecourseofscanning surfaces from the continued existence ofsurfaces being scanned. Parts of persistingsurfacesthatcomeintoviewduringheadmovementsdonot look the same as something coming into existence. Ifthis kind oftempo- ralexplorationhelpstorevealanextendedsurfacewithcontinued existence, and this is a core example ofperceiving, then thereis no added valueto invoking memoryto deal with the case. Many theorists presume thatmemoryisnecessarilyinvolvedintemporalexperience.Bymaking perceptionfoundationally temporal,Gibson forces thinkers to find more precisecasesfor discussionsofmemory. Thus,thereorganization ofthe psychological landscape impliedbyGibson'swork is immediately evident inthe caseofrelationsbetweenperceptionand memory. Toanticipate a widerrangeofpotentialcascadingoutofGibson'sideas,I'llmention threemore-"thinking,""identity,"and"motivation."Take"thinking" first. Astudent withan interestin "thinking,"who isat home withGib- son'sideas,wouldbeinclinedtoeschew"thinking"asanabstract, disembodied,objectless process.Rather the Gibsonianshouldenvisiona realpersonengaging inactual boutsofthinking. Underwhat conditions ofbodyandenvironmentdoesonethinkwell? Whataretherolesof aMw *,4--6e ** rmm WILLIAM MMACEJAMES J . GIBSONS ECOLOGICAL APPROACH fatigue,pain,sicknessfor example? Well-conditionedrunnerscanthink better atcertain times during their run. The locationswhere peoplethink clearlymatter. The chair,theroom, thelighting,thetemperature,andso forthmaybemorethanincidentalpropsbutpartofthinkingactivity. These factors rarelyappear inepistemologyor cognitive psychology,but theydo appear inbiography.The importanceofbothbody and placeon theopportunitiesforthinkingbyCharlesDarwinhavebeenrepeatedly described(e.g.,Browne2002). Darwin'sdevotiontohischairandhis wa l k "are well-known,as ishisstrugglewithill-definedsickness.Any- one who needs t o study or write or create art understands the need for an acceptable bodilystate and effective surroundings. A second example might be what psychologists think of as a person's identity.This is naturalt o formulate, fromGibson'sframework, as envi- ronmentallydependent(considertheeffectsofchangeofroutineand environmentthatmanypeopleexperiencewhentheyretiret odifferent placesanddifferent routines). Gibson'ssystem issaturatedwith the atti- tudethat "tobe"isto actandactionsrequiresettingsandobjects. Any senseof"whooneis"ismeaninglesswithouttheworldthatsupports action. To be sedentary requires chairs and couches, to be athletic requires surfacest o performon andsupporting equipment. What wouldit mean t o be a philosopher? There must be materials t o preserveinformation rel- evant to philosophers as well as occasionsfor usingsuch material. There needt o be other people(a rather significant part of any person'senviron- ment) to argue with. What I meant o indicate atthis pointis merely that Gibson'sworkleadsonetodiscoverrolesfortheenvironmentinafull analysisofwhatmightotherwiseseemlikementalisticorabstractcon- cepts with no materialimport. Finallyit is natural to consider motivation from Gibson'sstandpoint. Where environmental layouts present clear opportunitiesfor action, peo- ple feel inclined to perform those actions. The "urge"to slide on ice surely presents itselfdifferentlyinan emptyskating rinkwithsmooth ice com- paredt o a carpetedoffice. Or take a healthy five-yearold childt o a large emptyspacelikeauniversityfieldhouse.Whatarethechancesthata childwill"want"torun? This"motive"neednotberegardedasonly internal. I do not claim that Gibson himselfinvestigatedthinkingor iden-. tityormotivation.Hestudiedperception.Idoclaim,however,thathe developeda frameworkthat wouldleadone to include thebodyand the environmentinthestudyofanypsychologicalphenomenon,including "pure"thinking. Lest my enthusiasm for showing that Gibson'sideas can beextended widelybeseen as a surrenderofcriticalfaculties, Ihasten t o point out that Gibson himself did not extend his system casually or impe- rialistically.Hewasextraordinarilyambitious.Hewantedatotally comprehensivesystem,buthemovedcautiouslyandkepthisclaimst o what he knew he could defend on the basis ofevidence and argument. He once toldme that he was unsure ofwhether or not his system (emphasiz- ing the role ofthe ground) could apply to aquatic life. For those ofus who thoughtit was straightforwardt o make the case for therole ofthe envi- ronmentunderwaterasreadilyasontheground,thiswasstartling conservatism.Afteraseminar withphilosophersatSUNYBinghamton, hewonderedaloud, "whatdoes mytheoryhavet o sayabout concepts? What does mytheorysay about a conceptlike the integral?"(The italics representhis penchantformelodramaticemphasis on certain words ina way that matched the twinkle in his eye.) He regardedKant as the source ofenormous scholarly mischief. Accordingly, I never heardhim say Kant's namewithout apauset o makesure that all withinearshotcouldhearit rhymed with 'can't.'I'mnot aware that he even started to give an answer to that last questionabout integrals,buthewas willingto bechallenged byit. MOVESREQUIREDTOBUILDATHEORYOFPERCEIVING THEENVIRONMENT Ratherthanexplore the consequencesofGibson'sideasforthephi- losophyofmind,Ihavechosent ofocusthispaperon whatittakesto buildagoodpsychologyandepistemologyonenvironmentalfounda- tions. Whathas t o go on behindtheclaims? While it mightbesufficient for some purposes to demonstrate the needfor including the environment inan understandingofmind, I wouldliket o emphasize how Gibson did that.He didnotarriveathisconclusions simplyby wishingthemtobe trueorbyconstructinganargumentthatsuchideasmustbetrue.He arrived atmany conclusions on the basis ofexperimental results and puz- zlingoverconsistenciesandinconsistencies.Mostimpressivet o me was his abilityt o ferret out interdependenciesofconcepts in classicaltheories and t o buildan alternativesystem withitsown mutualdependencies. To makea system possiblein whichone could say that the environment was WILLIAMM.MACE directlyperceivedrequired(among otherthings) reformulatingthecon- cept ofthe stimulus (no small task), reformulating the assumedontology oftheenvironment(completelyunprecedented),reformulatingwhata "sense"couldbe, rejectingthe concepts of"space"and"time"and reor- ganizingwhatcouldcountas"memory."Thisisdemonstrablynota simple tweaking of othersystems but it is startling to consider how often it is readthat way.Commentators often presentGibsonas someone who asserts thatperceptionofthe environmentisdirect(correct) withoutan appreciationforthefullcontextrequiredbothtoexplaintheclaimand t o support it. It is common t o read him as if he shares most ofthe presup- positions and analyses with other perceptual psychologists save for a few. Forexample,itiscommont o ignorehiscritiqueoftheconceptofthe "stimulus"(Gibson1960) andt oregardhisalternativeconceptslike 'invariant'and 'information'as incidental preferences for different words that really mean the same things as 'stimulus'despite Gibson'sarguments that 'stimulus'isusedinvagueandcontradictory ways.Gibsondenied thatspaceandtimeweremeaningfulconceptsandhasgivengoodrea- sons. Theseconclusionsarelargelyoverlookedevenaspeopleusethe partsofhisworktheythinktheyunderstand. The ambition ofGibson's ideascanberegardedas exhilaratingor quixotic,butitisimportantto appreciate that an environmental philosopher signing on to examine Gib- son'sideas willbedrawnbackt o the core problems ofepistemology. Gibsonthoughtofhimselfas an experimental psychologistbuilding hisideasonasolidempiricalfoundation.Experimentsalwayswere importanttohim.Neverthelesshewasmindfulofrelevantphilosophy. Being an experimentalpsychologist,aware of andopen t o contributions fromphilosophy,wasconsistentwithhispedigree-WilliamJamesvia E.B.Holt. His teacherat Princeton in the mid1920s was E.B.Holt, who was in turn the student of William James(Heft 2001). Holt, known as one ofthe "New Realists"in the early 20th century, worked both as an exper- imental psychologist andasaphilosopher.Inhisbookon consciousness (Holt 1914). hestressedthatconsciousnesswasnot"inthehead"and that the objects ofcognitive activity wereessentialto understanding cog- nitiveactivity. ThroughHolt,GibsonabsorbedmuchofJames's"radicalempiri- cism."IsaythroughHoltbecauseJames'sessaysonradicalempiricism seemt o setthestageforGibson'sideasverywell,butthereislittleevi- dencethatGibsonstudiedthisaspectofJames. The JamesthatGibson studiedwithintensityandadmirationwasthePrinciplesofPsychology (James 1890),especially James'streatment ofthe stream of consciousness. Gibson appropriated the imagery ofa stream for perceiving,arguing that perceivingwascontinuousanduninterruptedfrombirtht odeath,an activitythat couldvaryindetailandintensity,butnevergotozero.As with James, when considering flow and discreteness, Gibson gave the pri- orityto flow. He stressed that discretenessprecipitatesout offlow;flow does not buildupfrom discreteness. DEFINING THESUBJECT MATTER JamesGibson'secologicalapproacht ovisualperception(1950, 1966, 1979) isan account ofhowan animalperceivesitsenvironment. The emphasis of that sentence should be on the word environment. Many psychologistsand neuroscientistscouldhonestlywrite the same sentence without subscribing t o what Gibson believed becausethey would empha- sizethewordhow,givinglipserviceatbestt o thewordenvironment. Most commonly, perception is studied as experience, whetherofthe envi- ronment or not. According to the received views, while some experiences mightbeoftheenvironment,theyneednotbeto qualifyasperception. Perceptionoftheenvironmentwouldbeasubsetofabroaderclassof perceptual experiences. AsformulatedbyGibson, however,perceptionisan achievement.It isasuccessword(Ryle1949; Shaw, Turvey,andMace1982) reserved onlyforcasesofperceptionofthe environment. The phrase'perception oftheenvironment,'forGibson,isalmostredundant(Isay'almost' because the self is also perceivedand it wouldseem confusingt o refer t o the selfas part ofthe environment, even though it is specified in the same ways-e.g.,opticallyforvision).Shaw, Turvey,andMace(1982) have added that perception,as treated in ecologicalpsychologyis not proposi- tional. It is not like a belief, which may be true or false. We(Shaw, Turvey, and Mace1982) argued that perceiving isa state ofaffairs. To perceive a placeto sitiscomparableto sitting on asitting place. We havesaid, fol- lowingHintikka(1975). thattheobjectofintentionandtheobjectof reference are the same. This is not to say that perceptionis ever perfect or complete. Perceptionintheinterestofactionscanbemoreorlessade- quate. It cannot betrue or false. This is a lot for philosophers to chew on. WILLIAMM.MACEJA Wethinkthe ecological position is pragmatic,and that what even though we argued that perception is not propositional, that this does not disqual- ifyit frombeingrelevantt o epistemology.We'llseethesepropertiesin Gibson'sdefinition of perceptionquoted atthe end ofthis section. The challenging task taken on by ecological psychologyis t o develop an understanding of awareness of the environment a tits best,its most sta- ble;thekindofapprehensionthatisthe"bottomline"ofexperience. Evenifillusionsandmisperceptionsgiveuspauseaboutwhatwecan trust,theperceptualtheoristmustexplainourbestperceptualaccessto the worldas wellas the errors. For example, consider how illusions typ- icallyare discussed. Anobserver isaskedto make a judgmentabout size, thestraightnessofaline,thelightnessofasurface,theweightofan object,or anynumberofotherproperties.Thenthat judgmentisevalu- ated in light ofthe "true"state ofaffairs. The illusion is "wrong."But how is the "true"state of affairs ascertained? How is "true"size, straightness, weight,or lightness determined? The same "sense"that is fooledin some limiting situation, say visionin visual illusions,also may be used to deter- minethe clarified, "real"state ofaffairsunderconditions offull viewing opportunity. That is thekindofcaseGibson ultimatelyaddressed. Ifthe stickinwaterlooksbent,wetakeitoutofthewatert o show thatthe stick"really"isnotbent.Butthestraightness we'resure of,that iscon- trastedwiththebentlookat thewaterline,isstilljudgedvisually. Supposewehavetwolinesofequallengthwitharrowheadsoneither end, those on one line facing in and those on the other facing out. This is the well-knownMuller-Lyerillusion. One line now looks longerthanthe other andthe argument from illusion leads some peopleto conclude that visionshouldnotbetrusted.However,ifwewantt oshow the"real" lengthofaline,wemeasureit. The matchbetweenlineson arulerand the line beingmeasuredis establishedthroughvisionjustas muchas the illusion was. Without a visual(or other perceptual) basis for determining the "true"state ofaffairs, an illusioncouldnotbedefined.Our criteria1 measurementisoftenestablishedbyvisionjustasmuchas theillusion itself. Withweight, welookatthe output ofthe scales weusefor weigh- ing.Nevertheless,peopleoftenproceedas ifthesubjectmatterofvisual perceptionisbetterrepresentedbytheappearanceofthestickinthe waterratherthanthestickout ofthe water;orbythe Miiller-Lyerlines ratherthanbythesightofthelinesas visuallycomparedt o markson a ruler. It'sall vision. I like to say that our goal, as ecologicalpsychologists, ist ostudy theperceptionofthemethodssectionofaresearchreport, ratherthantheintroductionorresultssections.Isaythisbecausein researchpapers, it is in the methods section where materials and circum- stancesaresupposedt obedescribed"objectively,"sothatother researchers can establish the same conditions. It is in the methods section whereresearcherssayhowlongthelinesare,howbrightthelightsare, how much the weights b'actually" weigh, where the materials are placed, who theparticipantsare,how manyofthem thereare atatime,andso forth,Howdoestheexperimenterknowthesethings? Largelythrough vision. Ifnot through vision,then through some other perceptual systems or combination ofthem. This isthe worldwe take for granted. Gibson's goal, I take it, was t o understand this situation. Bywhat means do people get t o a "bottom line"about theircircumstances? Gibson'sapproach wasnottheresultofasimple preferenceor even aphilosophicalargument.Itdevelopedfromexperimentalfindingsand frequent revisions t o accommodate those findings. An important possibil- ity that gradually dawnedon Gibson was that an adequate theorycould notbeconfinedt o psychologyor even neuroscience. Inthemost mature account ofhis position(1979). Gibson outlined a comprehensive position thatincluded(1)atheoryofwhatthereistobeperceived,thatis,an ontology, (2) a theory oftheinformationfor perceiving,and(3) a theory oftheactivity ofdetecting that information.Gibsonrealizedthat a com- prehensive theoryofperceiving the environmentrequiredcommensurate treatmentsofeach ofthesecomponents. The theoryofthe environment, the theory ofinformationfor that environment, and the theoryofdetect- ing information had to fit together. Ecological psychologycould not stand alone, but requiredthat the theorist identify the relevant physics and biol- ogy as well. That is, even thoughphysicsand biologyare crucial,Gibson recognizedthatphysicsdevelopedt o realizethegoalsofphysicistsand biologydevelopedforthepurposesofbiologistsdonotautomatically yieldthephysicsandbiologyappropriateto the psychology.Physics and biologythemselvescomeinmultiplelevelsanddo notrequirethatone levelbefixedasmorerealthanothers.Asheetofbrassisjustas real, physically, as a copper atom, and tissues and organs in animals are justas realas cells. It isinstructivet o examine the numberofhypothesizedpsy- chologicalprocesseswhosepurposeamountst o convertingonekindof WILLIAMM.MACE description into another. If, for example, one were to describe light at the eye in terms of photons, and an experience as the experience ofenviron- mentalsurfaces, theremightbeatemptationtoaskhow psychological andphysiologicalprocessesconvertedphotonstothe experience ofsur- faces.Alternatively,ifonefoundthatarrangementsofphotonscould carry patternsspecific to surfacestobeginwith,justassurfacescanbe saidtobemadeofatomsandmolecules,thenthelevelsofpatterning couldberecognizedas alternativedescriptionsoflight, The taskofneu- rophysiologyandpsychologycouldthenbetodiscoverthepatterns relevant to perception and then to understandhow these relevant patterns couldbeappreciated.No psychologicalprocess wouldneedtobeimag- inedforthe purpose of convertingone levelofdescriptioninto another. Gibsoncametorealizethatbuildinganecologicalpsychologyrequired coordinatedattentionto selecting(and sometimes developing) appropri- ate biologyand physics as well. To summarize essentialfeatures mentionedthus far inthe paperand to set the stage for furtherpresentationofGibson'sideas,I offerhislast definition ofperception inthe next paragraph. Gibson wrote and rewrote very carefully. Eachwordwasdeliberately chosenand eachphraserefers to a topic that Gibson elaborated in multiple nonredundant publications. Thisdefinition comesat theendof, andisasuccinctsummaryof,years ofinvestigation. The readershould note the centrality ofGibson'suseof the word'surface.'This is crucial to his ontology, andhis ontology is cru- cialto his epistemology. Asurface, forGibson, is areal,materialsurface inthe world. Wecan see it as such, we can experienceit directly, because arealsurface isoptically(for vision) distinctfrom non-real alternatives. In anumberofplaces,including his1979 book,helists important char- acteristicsofsurfacesanddistinguishesthesefromabstractconcepts, images, and representations(to list a few contrasting concepts). A surface reflects light. Think about it. An abstract triangle or circle does not reflect light. Animage on the retinaor inthebraindoes not reflectlight.Itis a longstanding puzzleofvisionto wonderhow animals can tellthe differ- ence betweenreflected light and radiant light whenit'sall the same at the eyeball.Establishingconditions for seeing surfaces implies one is making the distinctionbetweenreflectedand radiantlight. Surfaces have charac- teristictexture.Thetextureofthematerialconsistsofpatternswithin patterns that are revealed as one gets closer. Getting very close to a paint- ingdoes not revealthetextureofadepictedscene, butofthe canvasor whatever material was painted on. Very close scrutiny ofa museum paint- ing is the province ofthe art restoration expert and the structure revealed by scrutiny is one distinctionbetween a realsurface and an image or rep- resentation.Keepinginmindthefundamentalroleofrealsurfaces, connectedthroughout the environment, forGibson, Imove to the prom- isedquotation. "Toperceive is to be aware ofthe surfaces ofthe environment and of oneselfinit. Theinterchangebetweenhiddenandunhiddensurfacesis essentialto this awareness. Theseare existing surfaces;theyare specified at some points ofobservation.Perceiving gets widerand finerand longer andricherandfulleras theobserverexploresthe environment.Thefull awarenessofsurfacesincludes theirlayout, theirsubstances, theirevents and theiraffordances.Notehowthisdefinitionincludeswithinpercep- tion a part ofmemory, expectation, knowledge, and meaning-somepart butnot allofthosementalprocessesineach case"(Gibson 1979,255). What is essentialat the beginningofthisdefinition isGibson'siden- tificationofacoherenttopic-thedetectionofexistingsurfaces-and distinguishing this from the study ofthe appreciation ofsurfaces that do notexist. Existing surfaces cancome into viewbychanging the placeof observation, That is, if they exist, they can reflect light and be visible from some pointofview. Iftheydo comeinto view or go out ofview, theydo sointhecharacteristicwayspecifictochangesofviewpoint.Those changesdo notindicateanychangeintheexistenceofasurface.Other changes do affect surface existence-evaporation, disintegration, melting, and burning, for example (Gibson, Kaplan, Reynolds, and Wheeler1969). Noteagain that the topicofstudy here isthe existenceofsurfaces based on the differingbehavior ofoptical information structured ina real envi- ronmentbyrealsurfaces.Howmanypsychologistshavepresumedto grapple withexistence? Surfacesare notallthatare seen,ofcourse. Thesecondclausesays that one is aware ofoneselfin the environment. Gibson stressedthat this toowasamatterofopticalspecification,not"storedknowledge."The viewofeacheyeisboundedbyeyesockets,nose,andfacialfeatures. Much ofthe remainder ofthe body is visible as well. The perspectiveview on an arrangement ofsurfaces, beginning with the earth stretching to the horizon, isspecified, and part ofwhat there is to beseen. That'swhat he meansbyawareness ofthe environment and "oneselfinit." Seeing is not disembodied andit certainly is not perspective free. The surfaces are not abstract andare not merelysurfaces. Ashenotes,theyare madeofsub- stances,theymovecharacteristically(events), andtheysupport(afford) the activities of individual animals. Privacy, in the sense ofa unique point ofview,unsharedbyany otheranimal,isembodied. It isnot"internal" experience alone. No one else can see my nose, my cheeks, my body, from my pointofview. DIRECTPERCEPTION:ACQUAINTANCEAT FIRSTHAND AnassertionlongassociatedwithGibsonandhisfollowersisthat perceptionisdirect.Imaintainthat althoughtrue,italsohasbeenmis- leading.Directperception,forGibson,namessomethingwe'dlikean accountofandnotjusttheaccountitself. There presumablyisadiffer- encebetweenbeinginthe presenceof Johnandbeinginthepresence of some representation, some surrogate of John. Arewe likely to beembar- rassedbyasocialmiscueinfrontofapictureofJohninthesameway that we wouldbein the presence of John? This ought to go to the core of concernsforenvironmentalphilosophersofanyilk.Whydopeople travel? What'sthe difference between the real Yosemite and pictures from Yosemite? Letmecounttheways.Framedinthisway,aquestionlike "whydo peopletravel?"oughtt obeanabsurdquestion.Nevertheless traditionalphilosophers and psychologists have had nothing to say about it, so far as I can tell. Am I in love with my wife or a surrogate of my wife? Do I drive my children to soccer practicesand music lessons or do I drive representationsand imagesofthem t o variousevents? Arethe events we travelt orealevents?Ifnot,whywastegasoline?Gibsonprovidesa frameworkthat allows for thedistinctionbetweenfirst-handexperience (direct perception) and mediatedexperiences(experiences ofthe environ- ment with tools or movies or photos), then poses graded series of research questions. It makes sense to askofany theoreticalpositionhow it accountsfor directperceptionasthedifferencebetweenfirst-handexperiencesofan environmentandother experiences. Combining thetwo senses of"direct perception,"itisamusingto notethatone canaskifagivenposition's account ofdirect perceptionisdirect or indirect.Gibsonwrote, Directperceptioniswhatone getsfromseeing NiagaraFalls, say,as distinguishedfromseeingapictureofit.. . Directperceptionisthe activity ofgetting information from the ambient array of light. . .This isquitedifferentfromthesupposedactivityofgettinginformation fromtheinputs oftheoptic nerves, whatevertheymayprovetobe. (Gibson 1979,147) The contrast hereis to the picture. We can see the differencebetween picturesandthepartsoftheworldtheyare pictures of-thusthe"real" NiagaraFallsandthepictureofNiagaraFalls.Whereinliethediffer- ences? Ifone supposes that visionbeginswith theretinalimageand the retinalimageisbasicallya picture, thenone has obscured thedistinction betweenenvironmental entities (first-hand) and pictures ofthem (second- hand), or thedistinctionbetweentheopticarrayandaretinalimage. If one were t o insist that the retinal imageisthe basis for vision, and that it ispictorial, but that italsois the casethat the pictureofthe "real"Nia- garaFallsisdifferentfromthepictureofNiagaraFalls,theoriginal problem, howa"real"environmentalentityisdistinguishedfrom apic- ture ofit, reemerges. Seen as atopic,one couldviewGibson'ssolutions t o beone among many; and that competitors would offer alternative theories ofdirect per- ception. When construedas a process,"directperception"istakenas the theoryitselfandnotatopic.IdonotdenythatGibson'sapproachis directtheoryofprocess,justasbothsympatheticandunsympathetic commentatorssayitis,butIalso suspect that Gibson'ssolutions would bebetterappreciatedifthe problemtheyaddressed wereacknowledged. Atthemoment,IcannotthinkofanyoneotherthanGibsonwhohas embracedthetopicofdirectperceptionandofferedalternativetestable accounts. Workers in "virtual reality," especially video games, are likely t o cometheclosestt oappreciatingtheneedt odistinguishbetweenthe "real" world and pictured worlds. The appeal ofvirtual reality is a strong indicationthatpeopleknowfull wellthat thereisadifferencebetween "reality"anditssurrogates.Theprominentphilosopherofperception, FredDretske(1994), hasmisinterpretedGibson'sprogramasone solely aboutprocessandnotaboutobjects.Thiswasunfortunatebecause Dretskeformulatedtheoptionofconsideringdirectperceptiont obe about theobjectsofperceptionratherneatly,butthenassertedthat this was not what Gibson was writingabout. Inlightofthe above quotation WILLIAM M.MACEIAMESJ , GI BSON' SECOLOGI CAL APPROACH 207 from Gibson, and the materialaround it inthe same chapter, it is hard t o grasphow one couldmiss his point. For thephilosophersthatGibsonaddressedin1967, thekeystep in the analysis ofoptical patterns for Gibson was the 'invariant.'He pointed out that when there is change in a pattern, not everything changes. As one seesvaryingperspectiveonasolidsurface, texturesandotherinternal adjacenciesremainthesame.Gibsonarguedthatthereweremorethan enough suchinvariants to account for the perceptionofunchanging fea- turesof the worldamidthestandardsystematic changes suchas change ofviewpointinlocomotionor change ofilluminationasthesun'sposi- tionchangesrelativetotheearth.Detectinginvariants,heargued,not only provideda basis for experiencing a world that existedapart from us, butmadepossibleapublicworld, aworldthat couldbeexperiencedin common. Thatis,twopeoplecannotbeinthesameplaceatthesame time, but over time, they can occupy enough positions to extract the same invariants. Establishing abasisfor public knowledge is another emphasis ofGibson'swork.Notonlydoesheestablishabasisforpublicknowl- edge, but pressestherealityof the extended surface ofthe earth andthe sky as example "objects."The surface of the earth, as a perceptual object, is notan example one usuallyencountersin psychologyand philosophy. Yetit provides a very concrete theoretical anchor for an extended consid- eration ofpublicknowledge, the shared environment. Gibson'ssystem, as a fundamentalbasis for perception,for epistemology, is about this shared world. His systemisnotabout an abstraction,not about a category, but aboutthisindividual,specific world. In thenext section, Ishall sayabit more about this,but do notforget that itisashort step from appreciat- ing hisfocus on a reality that everyone can share to considerations ofthe qualities (for goodor i l l ) ofthat shared environment. INTERIORPERCEPTION Generalideasarebestkeptgroundedinspecificexamples.Thisis especiallyimportantforpresentingGibson'sideasbecausetherepresen- tativecasesarefrequently sodifferentfromtheexemplarsfixedonby scientists discussedinmost textbooks ofperception.Itake the perception ofinteriorstobeclosetoaminimalcase(short ofNiagaraFalls)for dramatizingthedirectperceptionsituation,somethingtobeperceived whichis not readily capturedbythinking about pictures. w* w208ETHICS The phraseinteriorperceptionwouldcommonlyleadpsychologists to expect a discussion ofsome kind ofintrospection, a looking inward. In thiscase itistheperceptionofinteriors that willbethefocus. ForGib- son, allperceivingoccurs withininteriors, theoutermost shellbeingthe earth-sky pair, ground or waterbelow, sky above. In an open terrain, the groundextendstothehorizoninalldirections. Itisimportanttonote that theobserveris surrounded,bothbythe groundandsky as environ- mentallowerandupperbounds andtheopticarraystructuredbythose features. The momentary,localviewthat an observergetsisasample of this surround. The sample isboundedby the eye sockets and the body on one (the limitofnear) end andthe horizon on the other (the limit offar). For vision, these extremes are components ofthe same optic array and do not,therefore,differinkind.Thatis,Gibsonrejectedthedistinction betweenso-calleddistalandproximal"stimuli."Traditionally,the "objects"ofthe environment are said to be "distal"t o observers and opti- cal patterns are said t o be "proximal7' becauseone can imagine a pattern impressed on the retina(how much closer, or proximal, can one get?).The proper appreciation of the proximal pattern is then said to give rise t o an experienceofthedistalobject.Gibsonarguedthatacarefulanalysisof whatonecouldmeanbythesethingsleftthemetaphoricalvalueof "near"and"far"equaling"opticalpattern"and"environmentalrefer- ent" t o be close to nil. Whereasit is intelligibleto analyze information in optical patternsforthenear(boundaries oftheheadandbody) andthe far(horizon). Byanalyzing the opticalstructure of"occludingedges"Gibson could distinguishbetween informationfor separation(occluding edges separate surfacesfrom one another and from partsofthemselves) and connected- ness in the same pattern.Ifthe observer turns his or herhead, portionsof thesurface thatarehiddenbytheheadcomeintoview,andpartsthat begininviewgooutofviewbyvirtueofocclusion. The newparts that comeinto vieware connectedt o whatwasseenbefore,as aretheparts thatgooutofview.Theboundariesaretheboundariesoftheviewing "window"asitwere,nottheextendedterrainitself, justasthebound- aries ofany window are not taken to beboundaries of the scene observed through the window. The visible terrainis boundedonly bythe occluding edgeofthehorizon.Texturecancomeintoviewandgooutofview reversibly withheadrotationonly ifthe surface to beviewedexists.Por- WILLIAM M.MACEJAMES J .GIBSON'SECOLOGICAL APPROACH tions brought into view are seen t o preexistand those that go out ofview are seent o continue t o exist. The revealingandconcealing oftextureatthe boundaries of the eye are seen t o be the resultofa change in the point ofview.In thisway, surfaces, beginning withthelargest one, the ground, are revealedasunitaryacrossmany successive, overlapping,views. This earth-sky enclosure is a fundamental perceptual "object"but hardly what leapst o mindasanassociation t o theword"object."Howeverfarone travels, the earth-skyshell remains fixed as an invariant frameworkfora person'sentirelife(before spacetravel). Everythingelsegoeson within that shell. At this outer limit, we spend our entire lives exploring features ofthis single connectedsurface, ifwe focus on the ground half. Lewis and Clark took in more ofit than ImmanuelKant did. Gibson'sinsight meant thatone couldexperience the connectedness ofan expended butexisting surface without seeing all ofit atonce-becausethe persistenceand con- nectednessofthe surfaceover time canbebasedon invariants extracted over time. Change of pattern over time, recall, does not necessarily change every aspect of a pattern. Again, invariance forms the basis for the (direct) perceptionofan extended,sharedenvironment.Environmental philoso- phersshould findthisausefulbasisforexaminingtheconsequencesof thisformulation for problems ofinterest t o them.Bybringing the episte- mologicalfocus to theindividualenvironmentthat weshare with others onearth Gibsonprovidesabasisforconnecting t o theconcerns of any- one else focusingonthe utilizationofthis common environment. MUTUALITY Throughout his writing, Gibson emphasized the reciprocity of animal andenvironment. Thephysicalworldassuchisnotan environment.It canbean environmentfora givenanimal. Ananimal cannot existapart fromitsenvironment. Eachimplies theother. Realperceivingisembod- ied.Theeyesockets-nose-head-bodythatoneseesarehere.The horizonis there.Wesaw that the perceptionofself wasincludedinGib- son'sdefinitionofperceiving.Ihavejustemphasizedthefundamental earth-skyinteriorassomething tobeperceived, especiallytheextended surfaceoftheearth.Theperceptionofthepersisting,connected,earth- sky,isplausiblyconnectedtotheperceptionofapersistingself.The continuityofselfoveralifetimeissupportedbythecontinuityofthe earth-skyframework. The reciprocitiesstillhold. Whenone looksatthe environment, one sees oneself,notas areflectionbut as a perspective on theenvironment.Wherethereisnoenvironmenttobeseen,asinan unstructuredfieldofhomogeneouslightcalledaGanzfeld,onemight expect a correlativelydiffusesense ofself. Gibson'smost famous idea t o reach a broaderaudience is his concept of affordance.This is meant to capture the fact that what animals see can bepartitionedrelativetothescaleoftheanimal.Asupporting surface thatisabout kneehighissomething that apersoncan siton. Stairs that allow climbing lookdifferent from stairs that do not. The factthat these arerelationalpropertiesdoesnotmake themmental.Thefactthat they are scaled to an animal means'thatthey are not strictly physicaleither. Yet therelationexistsintheworld. Thiskindofrelationalentity,reflecting environmentalpropertiesand, simultaneously,an animal'spointofview, isahallmarkofGibson'semphasesfromat least1950.Beforeaffor- dances, he stressed the concept ofthe occluding edge as a similar kindof relationalentity. Theopticalboundarywhereanopaquesurfacehides othersurfacesdependsonapointofview. Thereisnooccludingedge without specifyinga pointofview.It is clearwhat theroleofa pointof viewisinthedefinition,anditalso isclearthat thereisnothingmental about it. AsGibson saidrepeatedly,such entitiesare realandnotmyste- riouseventhoughtheyarerelational. The roleoftheanimalindefining anoccludingedgedoesnotgobeyondthatofthegeometricpointof observation.Theaffordance conceptusesmoreofthesizeandaction capabilitiesofan animal(what can be grasped with the hands, for exam- ple) than a mere point ofview, but the logic is the same. The arrangement andpropertiesofsurfacesintheworldcanbescaled relativeto the ani- mal'scapabilities.The relationalentities sodefinedarenotspooky,and canbesaidto beobjective, realpropertiesoftheworldtakenrelativeto givenanimals. CONSEQUENCESOFGIBSON'SREFORMULATION Thischapteralreadyhasstressedthatafundamentalrealization within ecologicalpsychologyis that the appropriate "stimuli"for perceiv- ing are not givenbysome other discipline. Boththe ontological bases and theinformationalbases(structure oflight when consideringvision) must beconsidered relativet o the scale ofa given animal. This does not mean, however, that such entities are created by the theorist. They exist and they 1 can be discovered. The embodied activities that constitute perceiving must bereformulated(Gibson 1966). Ifinformationintheenvironmentcon- tainsinvariantsthatmustbeseparatedfromvariants,thenexploratory activity to do this,on the part of animals, is necessary. Thus perceiving is expected t o bebetterinactive thanpassiveanimals. The active case that allows invariants t o be extractedis simpler than cases oflimited observa- tionthatcontainstoolittlevariety.Newperceptualactivitiescanbe identified. Because 'whatthere is to be perceived"is not "given"and obvi- ous from Gibson'spoint ofviewthis too can be the subject ofhypothesis and test, the normal proceduresofscience. Thus the perceptualscientist'sscope must include the physical world andthebiologicalworldaswellasthepsychological,andtheconcepts usedt odiscussthemmustbescaledt o bemutuallycompatible.Other- wise,there'sno reasonto expect the piecesto fit andonegetsasense of theenterpriseresemblingRichardGregory'sviewofperceptionwhichis atthe opposite extreme ofGibson's.Gregory says, Perceptions are constructed, by complex brain processes, from fleeting fragmentary scraps o fdatasignaled bythe senses and drawn from the brain'smemorybanks-themselvesconstructions from snippets ofthe past. Onthis view,normal everyday perceptions are notselections of realitybutareratherimaginative constructions-fictions-based. . . more onthe storedpastthanonthepresent. Onthis viewallpercep- tions are essentially fictions: fictions basedonpastexperience selected by presentsensory data. Currentsensory data(or stimuli) are simply not adequate directly to control behavior in familiar situations. . . .The fact isthatsensory inputs are notcontinuously requiredoravailable, and so we cannot bedealing with a pure input-output system. (Gregory 1972,707) See Mace(1974) foracollectionof otherquotations along the same lines. These are notdifficult to find. WhatGregory describes is a viewof the brain'sjobbasedon a severe mismatchbetween perceptual experience andwhat is given. Ifindeedallthat is"given"are "fleetingfragmentary scrapsofdata,"thenGregory'sviewofthejobofthebrainiscom- pelling-atthecostofanimalsurvivalbecomingalmostmiraculous. Moreover,thereisno way,inGregory'sview,to conceive ofan environ- ment that people share, that is public, and first hand. InGibson'streatment ofvision, the naturalcase to treatalways was a flow, what Gibson calleda flowfield. Without a flow, there would be no way to separate nonchanging structure from changing structure. I empha- sizeinvariantsearlier,buttheconceptofinvariantisdefinedrelativet o relevantvariation.Gibson'srelianceonflowimageryinhistheorizing, influencedbyJames,isanimportantcontrasttomostothertheorists. Gregory,as noted,isas good arepresentativeoftraditionalassumptions as any other. J. Hochberg (1982) is another. Each very clearly sees percep- tionbuiltupfromdiscretesources. Hochberg placesgreatstorein"the single glance."For Gibson, the flow is primary and stable entities emerge withinthe flow,as eddiesor whirlpools emergeintheflowofastream. Gibsondeclared, Theactofpickingupinformation, moreover, isa continuous act, an activity that isceaseless andunbroken. The seaofenergy inwhichwe liveflows and changes without sharp breaks. Eventhe tiny fraction of this energy that affects the receptors inthe eyes, ears, nose, mouth, and skin isaflux, nota sequence. The exploring, orienting, andadjusting ofthese organs sink to a minimumduring sleep but do not stop dead. Hence, perceiving isa stream, and William James'sdescription ofthe stream ofconsciousness (James 1890, Ch. 9) applies to it. Discrete per- cepts,likediscreteideas,are"asmythicalastheJackof Spades. (Gibson 1979,240) Ironically,totrustphysicstoprovidebiologyandpsychologywith immutable entities that biology and psychologyhave to work with can be viewedas asource ofcuttingpsychologyoff fromphysics,disconnecting it from a coherent science and making psychologya standalone, modular, discipline,a"special"science. Alternatively,asImentionedearlier,some ofushaveargued(Shaw,Turvey,andMace1982)thatpsychology, physics,andbiologycanbepartsofthesamesystemofscientificlaws, andthereforeofapiecewiththerestofscience,ifGibson'sstrategyis adopted, Then, and only then, can information and its detection be trans- parentandspecifictoitssources,Gibsontalkedaboutneedinganew optics, an ecological optics. Shaw and his colleagues have generalized that toecologicalphysics.Allthismeansisthatthe"physical"environment canbecut up atmanylevels and in many ways, each ofwhichserves its own purposes and no one ofwhich is more fundamental than the others. Thus, "surfaces that can support locomotion by elephants"are justas real as hydrogenatoms orphotons andfar morerelevantto thetasksofele- phantperceiving. Some writershavedescribedtheecologicalviewas maintainingthat WI LLI AMM.MACE the "physicalworld"is what is perceived. Ifso, the "physical"entities per- ceived are rather strange becausethey come withadefinite pointofview (e.g., the occluding edge, its special case in the horizon, and affordances). We argue that they are objective and real, but the incorporation ofa point ofview is contrary to the physicist'simpulse t o transcendperspectives,t o express truths that are perspective free. LetusnowreturntoGibson'sdefinitionofperception.Itfocuses partlyontheawarenessofexistingsurfaces,includingverylarge, extendedsurfaces-surfacesthat are much too large to take in with a sin- gle glance-upto thelargest surface, thesurfaceoftheearth(both land and water), whichis too large to take in during a single lifetime. Itnever- theless,inGibson'sapproach,isasingle,connectedentitythatcanbe perceived as such. It never can be perceived completely, ofcourse, but one learns more about its layout, substances, events, and affordances through exploration.Perceivingbecomes"widerandfinerandlongerandricher and fuller" as one explores. Reflect,then,on theendofGibson'sdefinitionofperception. "Note how thisdefinitionincludes withinperceptionapart ofmemory,expec- tation, knowledge,andmeaning-somepartbutnotallofthosemental processes in each case."Ifone can explore a surface over time, an instance ofextractinginvarianceovertime,torevealsomethingseparatedout from time,itisamostnoteworthy.It means thatthethingrevealed,the extended surface, isnotsubject to the sametemporalunitsas theexpio- rationprocess. Gibson stressed that changes of existence (like the creation or destruction ofa surface) are different from changes of what is in or out ofsight without a change in existence. Iftexture comes into sight by"dis- occlusion,"a change in whichthe surface is seen t o come into view rather thanexistence,then,asGibsonsaid,thesurfaceisseent o"preexist." Likewise,thepartsofsurfacesthatgooutofviewinocclusionarenot seent o bedestroyed, but t o continue to exist. Ifone acceptsthat invari- anceovertimecanbedetected,thenmanytraditionalpsychological categories do lookquite different. We realizethat what wehavethought ofas thedivisionof"processes"into perception,memory, cognition, and so on, areindeedenmeshedinahostofassumptions. Itiseasyto think about perceptionas referringto the presentandmemory t o the past.But whentheinformationrevealedovertimeisaboutpersistence, suchas a persisting surface, the categories threatento becomeless categorical. TheGibsonian,ecologicalapproachtoperception,beganaspure experimentalpsychology. The consequencesgo farbeyondexperimental psychology, however, t o all areas that intersect with psychology, including epistemology.Gibsonprovidesasystemthatshowsbasesforasserting what is importantly real in the world, how animals can perceive those real things,anddistinguishthem,perceptuallystill,fromnon-realthings. There isnodemarcation,inGibson, between"pure"and"applied"sci- ence. Byextending his work t o affordances, the realm of practical activity, heisoffering a wayto conceptualize, within his system, what other theo- ries setapart as mereapplications. Not only hasGibsonshown a way to maketheenvironmentcentraltoepistemology,buthehasdone so ina waythat can provideafoundation t o pursuea varietyoftopicsofinter- esttoenvironmentalphilosophers.Ihavementionedseveralofthosein thecourseofthispaper.ForGibson,thedifference betweenfirsthand encounters withtheenvironmentandnon-first handencounters, canbe conceptualized. Whatare the consequences? Peoplecan haveencounters withpristineforestsandwithgarbagedumps.Theycanbetoldabout them. What are the differences between first-hand encounters and second- handknowledge?Thiswouldseemtobeascientificallyand philosophicallyempoweringsetofideaswhichcanleadtonumerous fruitfulexplorations. REFERENCES Browne, J. 2002. Charles Darwin: The PowerofPlace.Princeton: Princeton Uni- versity Press. Dretske, F. 1994. "MeaningfulPerception." InVisual Cognition: AnInvitationto Cognitive Science(pp. 331-352),edited by S. Kosslynand D.Osherson. Cam- bridge: MIT Press. Gibson, J. J.1950. The Perception oftheVisual World. Boston: Houghton Mif- flin. . 1959. "Perceptionas aFunction of Stimulation." InPsychology: AStudy ofa Science, I (pp. 456-Sol),edited by S.Koch. New York: McGraw-Hill. . 1960. "TheConcept ofthe Stimulus inPsychology." AmericanPsycholo- gist(16):694-703. . 1962. "Observations on Active Touch." Psychological Review(69): 477- 491. . 1966. The SensesConsidered asPerceptualSystems.Boston:Houghton Mifflin. WI LLI AMM.MACE JAMES J.GIBSON'SECOLOGICAL APPROACH . 1967. "NewReasons for Realism."Synthise (17):162-172. . 1974."A NoteontheRelationbetweenPerceptualandConceptual Knowledge." Unpublished manuscript. Available online athttp://www.trincoll .edu/depts/ecopsydperils/folder6/perceptcon.html~ . 1979. The Ecological Approach to Visual Perception. Hillsdale, NJ:Law- rence Erlbaum Associates. Gibson, J. J., G. Kaplan, H. Reynolds, andK. Wheeler. 1969. "TheChange from VisibletoInvisible:AStudyinOpticalTransitions."Perception6r Psy- chopbysics 5:113-1 16. Gregory, R.L. 1972. "Seeingas Thinking. AnActive Theory ofPerception." Lon- don Times Literary Supplement, 23 June, 707-708. Heft, H.2001.Ecological PsychologyinContext: JamesGibson, Roger Barker, andtheLegacyofWilliam James'sRadical Empiricism.Mahwah,NJ:Law- renceErlbaum Associates. Hintikka, J.1975. TheIntentionsofIntentionality andOtherNewModels for Modalities. Dordrecht, The Netherlands: D. Reidel. Hochberg, J. 1982. "How Big is a Stimulus?" InOrganization and Representation inPerception(pp. 191-217),editedbyJ.Beck.Hillsdale, NJ:Lawrence Erl- baurn Associates. Holt. E.B.1914. The Concept ofConsciousness. London: George Allen. Kanizsa, G, and W. Gerbino. 1982. "Amodal Completion: Seeing or Thinking?" In OrganizationandRepresentationinPerception(pp.167-190),editedby J. Beck.Hillsdale, NJ:Lawrence Erlbaum Associates. Mace, W. M.1974. "Ecologically Stimulating CognitivePsychology:Gibsonian Perspectives." InCognition and the Symbolic Processes, I (pp. 137-164), edited byW. WeimerandD.Palerrno. Hillsdale, NJ:Lawrence Erlbaurn Associates. . 1977. "James J. Gibson's Strategy for Perceiving: AskNot What'sInside YourHead,ButWhatYourHead'sInsideOf."InPerceiving,Acting,and Knowing (pp. 43-65), editedbyR.E.Shaw and J.Bransford. Hillsdale, NJ: Lawrence Erlbaum Associates.9 . 1986. "J. J. Gibson'sEcological Theory ofInformation Pickup: Cognition from the Ground Up."In Approaches toCognition:Contrasts and Controver- sies(pp.137-157),editedbyT.J.KnappandL.Robertson.Hillsdale,NJ: Lawrence Erlbaum Associates. Shaw, R.E.,M. T. Turvey,and W. M. Mace.1982. "Ecological Psychology: The Consequence ofaCommitment toRealism."InCognition and theSymbolic Processes,I1 (pp.159-193),editedbyW. WeimerandD.Palermo.Hillsdale, NJ:Lawrence Erlbaum Associates. NOTESONCONTRIBUTORS TimAdamsoninAssistantProfessorintheDepartmentofPhilosophy and ReligionatIowa WesleyanCollege and Adjunct Professor ofReligion atthe University ofIowa. He is author ofseveral articles dealing with the role ofembodiment and metaphorin human cognition, the links between phenomenologyandcognitivescience,andKant'snotionofReflective Judgmentas amodelfor contemporaryapproaches t o cognition. E-mail: tadam@iwc.edu JimCheney(aka ShagbarkHickory) isProfessorEmeritus atthe Univer- sity of Wisconsin- Waukesha, and currently visiting flora with Zenlite. He hasbeenaRockefellerFoundationVisitingHumanitiesFellowwiththe NativePhilosophyProjectat LakeheadUniversityinThunderBay, Ontario, and theinaugural VisitingScholar ofEcophilosophyandEarth Educationat MurdochUniversityinWesternAustralia.E-mail: shagbarkhickory@sbcglobal.net I r i sh Glazebrook is Associate ProfessorofPhilosophyatDalhousie Uni- versityinNovaScoria.Herresearchinterestsareinenvironmental philosophy,philosophyofscience and technology, feminism, and Heideg- ger. Her recent book, Eco-Logic: Erotics ofNature,is in progress. E-mail: pglazebr@dal.ca WilliamM. Mace isChair and ProfessorofPsychology atTrinityCollege inHartford,Connecticut.He isafoundingdirectoroftheInternational SocietyforEcologicalPsychology(ISEP), performstheexecutivefunc- tionsoftheSociety,andiseditorofthejournal,Ecological Psychology. He has held visiting positions atCornell Universityand the University of Texasa tAustin,and has acontinuing affiliation withtheCenterfor the EcologicalStudy of Perceptionand Action(CESPA) attheUniversityof Connecticut. E-mail:William.Mace@trincoll.edu BonnieMannisAssistantProfessorofPhilosophyat theUniversityof Oregon in Eugene. Before returning to academia full-time she spent many years working inanti-domestic violenceorganizations, homelessshelters, andwithanumberoffeministactivistgroups.E-mail:bmann@ uoregon.edu Andrew Picketing is Professor ofSociology atthe UniversityofIllinoisatUrbana-Champaign.HeistheauthorofConstructionQuarks andThe Mangle ofPractice,andisthe editorofScience as Practiceand Culture. He is currently completing a book on the history of cybernetics in Britain. E-mail: pickerin@uiuc.edu Christopher J.Prestonisan environmental philosopher withexpertisein philosophy ofscienceandfeminist epistemology.He has workedforthe National ParkService and has been involvedwithissues concerning com- mercialfishingandoil-spillresponseinAlaska.Heistheauthorof GroundingKnowledge:EnvironmentalPhilosophy,Epistemology,and Place (2003).Currently he is AssistantProfessor ofPhilosophy at the Uni- versityof Montana. E-mail: christopher.preston@mso.umt.edu Holmes Rolston 111is University DistinguishedProfessor and Professor of PhilosophyatColorado State University. He was TempletonPrize Laure- atein2003. Advocatingenvironmentalethics,hehaslecturedonseven continents. He is featured in JoyA. Palmer, ed., Fifty Key Thinkers on the Environment.E-mail:rolston@lamar.colostate.edu Mark Rowlands is ProfessorofMental and Moral Philosophyat the Uni- versityofHertfordshire, andhaswrittenanumberofacademicbooks and articles on philosophyand ethics. Currentlyhe is writing for the gen- eralreaderonphilosophyandpopularculture.Hehashadnumerous mediaappearances. TworecentpublicationsareThe Philosopher a tthe End oftheUniverse(2003) and Everything I Know I Learned fromTV (2004).E-mail:m.rowlands@herts.ac.uk OUR THANKS TO THEREFEREES BairdCallicott Claudia Card Chris Cuomo Deane curt i n Kevin DeLuca Frederick Ferrk GretaGaard TrishGlazebrook Christine Harold Dale Jamieson AndrewLight Holmes Rolston I11 Catriona Mortimer-Sandilands Gary Varner Steven Vogel Anthony Weston Clark Wolf