2 + 2 = 42 + 2 = 4

Your mother loves you.Your mother loves you.

Death is a part of life.Death is a part of life.

The sky is blue.The sky is blue.

Truth PowerPointTruth PowerPoint

What do we mean What do we mean when we say we when we say we

“know” something?“know” something?

Ex. “I know my car is in the Ex. “I know my car is in the parking lot.”parking lot.”

If If PP is any proposition, what requirements must is any proposition, what requirements must we meet to claim we meet to claim PP??

a) We must a) We must believebelieve that that P P is the case is the case (knowledge implies belief, but belief (knowledge implies belief, but belief does not imply knowledge-assumptiondoes not imply knowledge-assumption

b) We have evidence for justification or b) We have evidence for justification or warrantability (sufficient reason for warrantability (sufficient reason for belief … belief … how much is enoughhow much is enough?)?)

c) Knowledge c) Knowledge requires truthrequires truth!!

Knowledge is warrented, true belief. To Knowledge is warrented, true belief. To understand knowledge, we must understand understand knowledge, we must understand warrantability and truth.warrantability and truth.

Modes of WarrantabilityModes of Warrantability Logical warrantability – laws of logicLogical warrantability – laws of logic

Semantic warrantability – analyzing the meaning of wordsSemantic warrantability – analyzing the meaning of words

Systemic warrantability – derive warranty from logical Systemic warrantability – derive warranty from logical

interdependence of all propositions in a deductive systeminterdependence of all propositions in a deductive system

Empirical warrantability – confirmatory relation to specific Empirical warrantability – confirmatory relation to specific

qualities of first person experience, sometimes qualities of first person experience, sometimes

conformation conformation

needed outside selfneeded outside self

Warrantability does not imply truthWarrantability does not imply truth

Warrantability = justification and evidenceWarrantability = justification and evidence

Warrantability comes in degrees, truth does notWarrantability comes in degrees, truth does not

What is Truth? What is Truth? What is Truth? What is Truth? •Truth is closely Truth is closely connected to connected to knowledge and knowledge and beliefbelief•““The The contemplation of contemplation of truth and beauty is truth and beauty is the proper object the proper object for which we were for which we were created” created” William William HazlettHazlett

I.I. The CorrespondenceThe CorrespondenceTheory of TruthTheory of Truth

Most popular theory of truth Most popular theory of truth Plato, Aristotle & Aquinas Plato, Aristotle & Aquinas Truth is an agreement Truth is an agreement

between a proposition and a between a proposition and a factfact

Bertrand RussellBertrand Russell (1872-1970) (1872-1970) states that there is a realm of states that there is a realm of facts that exists independent facts that exists independent of us (e.g. Toronto is the of us (e.g. Toronto is the capital of Ontario) … “the capital of Ontario) … “the truth” of a belief depends on truth” of a belief depends on whether the belief whether the belief corresponds to the corresponds to the independent factindependent fact

Critiques of the Critiques of the Correspondence TheoryCorrespondence Theory

Critics ask “what is a Critics ask “what is a fact ?”fact ?”

Assumes that we Assumes that we know our experience know our experience of things and also of things and also facts about the worldfacts about the world

II. The Coherence II. The Coherence Theory of Truth Theory of Truth

Adherents include Leibniz, Adherents include Leibniz, Spinoza and Hegel Spinoza and Hegel

A statement is true if it is A statement is true if it is consistent with other consistent with other statements that we regard as statements that we regard as truetrue

Brand Blanchard (1892-1989) Brand Blanchard (1892-1989) said that “an agreement said that “an agreement between judgments is best between judgments is best described not as a described not as a correspondence but as a correspondence but as a coherence.” coherence.”

Geometry constructs an Geometry constructs an entire system of truths by entire system of truths by building on a few basic building on a few basic axiomsaxioms

Critique of the Critique of the Correspondence Theory Correspondence Theory

Does not distinguish Does not distinguish between consistent truth between consistent truth and consistent errorand consistent error

A judgement may be true if A judgement may be true if it accords with other it accords with other judgments, but what if judgments, but what if other judgments are false? other judgments are false?

Result is a system of Result is a system of consistent errorconsistent error

What does the first What does the first judgement cohere with? judgement cohere with?

III. The Pragmatic TheoryIII. The Pragmatic Theory Pragmatism develops in the Pragmatism develops in the

west …. William James west …. William James (1842-1910) and John (1842-1910) and John Dewey (1859-1952) …if Dewey (1859-1952) …if something works it is true !something works it is true !

There is no absolute truth There is no absolute truth … truth is dynamic … truth is dynamic changing, subjective and changing, subjective and relativerelative

See if the belief satisfies See if the belief satisfies the whole of human nature the whole of human nature over a long period of timeover a long period of time

A statement is true if A statement is true if people can use it to get the people can use it to get the results that they needresults that they need

Critiques of the Critiques of the Pragmatic Theory of Pragmatic Theory of TruthTruth

Critics argue that Critics argue that truth depends on truth depends on the fallible the fallible judgments of judgments of human communities human communities … unacceptable… unacceptable

If truth is not If truth is not absolute but absolute but relative, who is to relative, who is to decide what is true decide what is true and what is not? and what is not?

Cartoons on Truth Cartoons on Truth

The Instrumentalist The Instrumentalist ViewView

Related to the Pragmatic Related to the Pragmatic Theory of TruthTheory of Truth

Scientific Theories are true Scientific Theories are true if they enable us to if they enable us to accurately predict what will accurately predict what will happen ...they work !happen ...they work !

No one believed that No one believed that Copernicus’ theory was an Copernicus’ theory was an accurate description of the accurate description of the solar system but it solar system but it explained the motion of the explained the motion of the celestial spheres celestial spheres

The Realist ViewThe Realist View

Related to the Correspondence Theory of Related to the Correspondence Theory of TruthTruth

Scientific theories are true or false in so far as Scientific theories are true or false in so far as they describe what they describe what reallyreally exists exists

The goal of science is to explain the world as it The goal of science is to explain the world as it really isreally is

The scientist “discovers” the scientific truthThe scientist “discovers” the scientific truth

The Conceptual Relativist The Conceptual Relativist ViewView

Related to the Coherence Related to the Coherence Theory of Truth and the work Theory of Truth and the work of Thomas Kuhnof Thomas Kuhn

A true scientific theory A true scientific theory coheres with the conceptual coheres with the conceptual framework accepted by a framework accepted by a community of scientistscommunity of scientists

Our theories about reality Our theories about reality influence what we think we influence what we think we are seeing when we observe are seeing when we observe reality reality ….we cannot reality reality ….we cannot independently know the real independently know the real worldworld