Theories of Truth

Truth

To say of what is that it is not, or of what is not that it is, is falsity.

To say of what is that it is, or of what is not that it is not, is truth.

Truth and Action

True beliefs lead to successful actions.

Truth and ActionSuppose:You desire to hang out with your friends for another hour.You desire to deposit your paycheck in the bank.You prefer to deposit your check to hanging out with your friends.You believe the bank closes at 6pm.You believe that if you hang out with your friends for another hour, you can still deposit your check.Plan: hang out, then go to the bank.

Truth and Action

True belief case:You get to hang out and deposit your check.

False belief case:Your greatest desire (deposit check) is unsatisfied.

The Aim of Belief

One view of what belief is, is that belief is the mental state that ‘aims at’ truth.

Knowledge and Truth

A mental state is factive if you can only be in that state when the content of that state is true.

Knowledge is factive: If you know that p, then p must be true.

Grice’s MaximsQuality: Try to make your contribution one that is true.

Quantity: Make your contribution as informative as is required (for the current purposes of the exchange); Do not make your contribution more informative than is required.

Grice’s Maxims

Relation: Be relevant.

Manner: Be perspicuous.

FloutingThe form of a flouting inference is something like this:

“The speaker is openly failing to fulfill such-and-such maxim, though I have strong reason to think the speaker wants the purpose of the conversation to succeed. The only good reason to be uncooperative, given that, would be if q. So the speaker must want me to believe q.”

Flouting QualityOne typically flouts the maxims of quality when one engages in irony, metaphor, understatement, and hyperbole. For example: The speaker said “Dick Cheney is a monster”; but he can’t really believe that Cheney is a monster, because monsters don’t exist; he must really mean that Cheney is a terrible person.

Why We Are So Clever

“[A] creature that knows what would make its thoughts true and what would cause it to have them, would be in a highly advantageous epistemic position:…”

Why We Are So Clever

“It would be able, with premeditation, to cause itself to have true thoughts. In particular, to construct, with malice aforethought, situations in which it will be caused to have the thought that P if and only if the thought that P is true.”

Why We Are So Clever

“I think it's likely that we are the only creatures that can think about the contents of our thoughts.”

Background

Criteria vs. Definitions A definition of ‘true’ gives the meaning of the word ‘true.’

A criterion for truth gives us a means of telling whether something is true.

Some “theories of truth” are better thought of as giving criteria rather than giving truth-definitions.

The Bearers of TruthWhat sorts of things can be true?

Sentence types?Sentence tokens? (utterances)Propositions?

Types vs. Tokens

Worries about Propositions

1. General issues with abstracta2. A new kind of “going together” (unity of the proposition)

The Correspondence Theory

The Correspondence Theory

A correspondence theory of truth views sentences/ propositions that are true as ones that “correspond” with the facts.

Truth the goddess is often depicted holding a mirror: truth mirrors the way the world is.

Logical Atomism

For (early) Wittgenstein and (atomism-period) Russell, the world was composed of objects, properties, and relations “going together”.

The Facts

For example, one fact might be an object, Michael, another object, this particular hat, and the relation of wearing.

These objects and relation “go together” to make a fact.

CorrespondenceTruth then is a correlation between sentences/ propositions and the facts that make them true.

“Michael is wearing a hat”

“Grass is green”

“Goats wear glasses”

The Facts

Problem: which objects and properties going together constituted the fact that Michael is not wearing a blue shirt?

We need this fact to correspond to the sentence “Michael is not wearing a blue shirt.”

Compositional AnalysisMaybe the correspondence theory should be applied to the atomic sentences, and more complex sentences have their truth-conditions determined by the truth-conditions of their atomic parts:

“NOT: P” is true iff P is not true (does not correspond with the facts).

The Facts

“Michael is wearing a blue shirt.”

So: “Michael is not wearing a blue shirt” is true.

Does not correspond

The Coherence Theory

Neurath’s Raft

What Is Coherence?

• Can’t be satisfiability!• Not mere consistency• Comprehensiveness• Truth-likeness• Criterion or definition?

The Pragmatist Theory

William James

• 1842-1910• American philosopher/

psychologist

Charles Sanders Peirce

• 1839-1914• American philosopher/ logician/

mathematician/ chemist• Along with Frege, independently

discovered modern logic

John Dewey

• 1859-1952• American philosopher/

psychologist/ education reformer• Advocate of democracy and

education

Pragmatism

“There can be no difference that makes no difference.”

Peirce’s PragmatismCorrect definition of truth: correspondence with reality.

Way to tell whether something is true: use science.

Criterion for truth: what we believe ‘at the end of inquiry’.

Primitivism, Redundancy, Delfationism

Perennial Options

In philosophy, two options are always available: primitivism and deflationism.

Primitivism

The primitivist theory says that truth is a primitive… there’s nothing more to say.

Some Equivalences

“Snow is white” is true ↔ Snow is white“Snow is purple” is true ↔ Snow is purple

“Michael is a philosopher” is true ↔ Michael is a philosopher“Michael is a shark” is true ↔ Michael is a shark

And so on…

Frank P. Ramsey

• 1903-1930• Died at 26• Influential philosopher/

economist/ mathematician• Created a branch of

mathematics ‘Ramsey Theory’• Good friend of Wittgenstein

The Redundancy Theory of Truth

Ramsey’s view of truth was that ‘it’s true that p’ is just a fancy way of saying p.

‘Is true’ is redundant. We don’t need to say it, but we can if we have extra time on our hands.

Virtue of Redundancy

Saying something ‘is true’ is not saying anything in addition to just saying that thing.

So the question of ‘what are the bearers of (the property of) truth?’ goes away: there is no property.

Problems for Redundancy

Consider the sentence ‘what Michael said is true.’ Try to say this without ‘is true’.

Attempt: Michael said ‘poodles like noodles’ and poodles like noodles; OR Michael said ‘lemurs have femurs’ and lemurs hate femurs; OR Michael said ‘llamas star in dramas’ and llamas star in dramas; OR….

Problems for Redundancy

Consider the sentence ‘everything Michael said is true.’ Try to say this without ‘is true’.

Attempt: If Michael said ‘poodles like noodles’ then poodles like noodles; AND If Michael said ‘lemurs have femurs’ then lemurs hate femurs; AND If Michael said ‘llamas star in dramas’ then llamas star in dramas; AND….

Problems for Redundancy

Consider the English sentence “‘Der Schnee ist weiss’ is true” Try to say this in English without ‘is true’.

Attempt: If ‘Der Schnee ist weiss’ translates to ‘poodles like noodles’ then poodles like noodles; AND If ‘Der Schnee ist weiss’ translates to ‘lemurs have femurs’ then lemurs hate femurs; AND If ‘Der Schnee ist weiss’ translates to ‘llamas star in dramas’ then llamas star in dramas; AND….

Deflationism

The deflationist theory of truth says that truth is not redundant, but that ‘is true’ is simply an expressive device.

You could have a language with no ‘is true’ that could say everything English can say.

Infinitary Conjunction and Disjunction

Everything Michael says is true:&{ p | if Michael says “p”, then p }

That one thing Michael said is true:v{ p | Michael said “p” and p }

Problems for Deflationism

We began with the observation that true beliefs lead to successful actions.

Why should this be so if ‘is true’ is a dispensable expressive device.