Philosophy 225F, Week 2: John Searle

Three Crucial Features of Our Worldview

• 1 External realism—there is a world independent of our representations

• 2 Intentionality—our representations are about that external reality; some representations have this aboutness intrinsically (e.g., perception), in other cases it is learned & assigned (e.g., language)

• 3 Correspondence theory of truth—our representations are true if & only if they correspond to the independent facts

What IS Realism?

• It is the claim that there is no logical connection between the existence of reality & our representations of it

Antirealism

• This is the thesis that the existence of the objects in the world are logically dependent on our representations of them

Searle’s Argument for ER

Searle Provides a Transcendental Argument for External Realism

Moore’s Proof

• Moore tried two prove the existence of the external world by claiming that he knew that he had two hands

The Brute Force Argument

• Insert an explicit denial of the Background presupposition & see what happens

• E.g., Mt. Everest has snow & ice near the summit, but external reality has never existed

Understanding Denials of the Background Presupposition

• The second clause doesn’t just contradict the first—it denies a condition that is taken for granted in the normal understanding of the first

Truth & Correspondence

Using Disquotation

• Disquotation is said to give us the truth conditions of a sentence

• Thus, “Snow is white” is true in English if & only if snow is white

Two Extensions of Disquotation

• “Schnee ist weiss” is true in German if & only if snow is white

• “I am hungry” said by speaker S at time t is true if & only if S is hungry at t

How Disquotation Supports the Correspondence Theory

• Searle says that the condition stated on the right specifies the truth condition of the sentence mentioned on the left—it gives the state of affairs or fact that the statement on the left must correspond to in order to be true

Semantic Realism

• Philosophy 225 F

• Week 2

• September 18, 2001

• Gottlob Frege

• On sense & reference

Gottlob Frege 1848-1925

On Sense & Reference

1892

Response to 1879 Begriffsschrift

Four Classic Puzzles: 1 Identity Sentences

• 1 How can true identity sentences be informative?

– They can’t be if “a = b” & “a = a” say the same thing

– If, e.G., “The morning star = the evening star” & “the morning star = the morning star” both say that the planet Venus is identical with itself

2 Failure of Substitutivity of Coreferential Expressions

• The codesignative expressions

– “The morning star” & “the evening star”

• Cannot be substituted for one another in the context “X knows that a = b”

• The ancient Babylonians knew that

• The morning star was the morning star

• But they did not know that

• The morning star was the evening star

Another Illustration

• It is mathematically certain that

– 9 is odd

• The number of planets = 9

• But it is not mathematically certain that

– The number of planets is odd

• There might have been 8 or 10 planets

3 True Negative Existentials

• “The present king of France does not exist”

– If there is no king of France, then the subject term has no reference & so the sentence is meaningless

– On the other hand, if there is a king of France, then the sentence is meaningful, but false

4 Vacuous Names

• “The present king of France is bald”

– Can’t be counted as true because the class of all bald people does not include a present king of France

– Nor can it be counted as false since the class of not bald people does not include a present king of France either

4 Vacuous Names

• Appears to violate law of the excluded middle, that either P or not-p

Why We Need Senses

• Why expression/sign & reference/object are not enough

• If signs are only distinguished formally or syntactically (I.E., By their shapes), then the cognitive value of a = a & a = b will be essentially the same

Frege’s Earlier Solution Trivialized Identity

• If we only have signs & objects to work with

• Then the fact that

– Polio = A virus of a certain sort

• Is an arbitrary truth of lexicography

• But nothing can prevent us from using one sign to name any object we like

What Are Fregean Senses?

• A sense is

– The manner in which an object is designated

– It is the way in which the reference is presented

• An expression’s sense contains its mode of presentation

Senses & Aspects

• When a word has a reference, a sense illuminates an aspect—a property or characteristic—of the object of reference

Knowing a Language

• To understand a language is to know the senses expressed by its signs

Searle’s Criticism of Frege

• For Frege the sense of “Aristotle” is expressed by the conjunction of all the predicates true of Aristotle.

• Pupil of Plato & teacher of Alexander the great & born in Stagira, etc.

– Makes “Aristotle was Plato’s pupil” analytic.

Searle’s Criticism of Frege

• Searle’s alternative.

– Have the sense be expressed by a weighted disjunction of predicates.

– This is called the Cluster Theory of Names.

Frege’s Response to Another Objection

• Frege realized that

– People assign different senses to proper names—particularly to their own names

Frege’s Response to Another Objection

• In logic or a perfect language, such ambiguity would not be tolerated

• Frege says we get by in natural languages as long as the reference is the same

Terminology

• Expressions, senses & references

• Expressions express their senses

– They designate or stand for or refer to or denote their reference

Vacuous Names

• One of the big roles of the idea of a word’s sense is to explain the significance of vacuous names

– For a name can have a sense without having a reference

Indirect Speech

• Quoted speech

– John said “Mary stole the bike”

• Here we talk about the words used

Indirect Speech

• Reported speech

– John said that Mary stole the bike

• Here we talk about the sense expressed

• The indirect reference is the customary sense

Frege’s Platonism

• Reference & sense & idea are all different

– Ideas are subjective while senses may be the common property of many

• Mankind has a common store of thoughts that are transmitted from one generation to another

Frege’s Telescope Analogy

• The moon itself is the reference

– But our observation is mediated by

• The real image projected by the telescope’s object glass—which corresponds to the sense

• And our observation is mediated by our retinal image—which corresponds to the idea

Can We Know That Our Words Have Reference?

• Frege’s answer is that when we use a referring expression such as “the moon,” we presuppose or intend a reference

– We mean to be talking about the real thing—not our ideas—our ideas are normally not in question

Sentences Refer for Frege

• The reference of a declarative sentence is a thought (or proposition)—a kind of sense

• This is not the subjective act of thinking, but its objective content—its sense—which is a public & shared property

Vacuous Names & Truth Value Gaps

• “Odysseus was set ashore at Ithaca while sound asleep”

– “Odysseus” is probably vacuous/empty

• So the whole sentence probably lacks a reference

• So Frege says the sentence is neither true nor false

Sentences Refer to Truth Values

• When we are concerned about a sentence’s truth value, the thought it expresses is not enough

• We are concerned about its reference whenever we are concerned about its truth

– So a sentence’s reference is its truth value sentences refer to truth values

Nonextensional (Epistemic, Modal) Contexts

• In contexts like

• X knows that/believes that x is F

– The truth value of “x is F” is irrelevant

– All that matters is the thought expressed

• So the reference of the subordinate clause is the thought (the customary sense)—not the truth value (the customary reference)

• So only synonyms can be interchanged

The Same Considerations Hold for Names

• We all know that 9 = 9

– But I only remember that

• 9 = the number of planets when I read about it in philosophy examples

– So knowing that 9 = 9 does not entail

• Knowing that 9 = the number of planets, even though 9 = the number of planets

Frege’s Treatment of Psychological States

• Thoughts & desires involve processing representations/senses

• If near the end of the battle of waterloo Wellington was glad that the Prussians were coming, then the basis for his joy was his conviction—not the fact that they were coming

A Similar Case

• Columbus inferred from the roundness of the earth that he could reach India by traveling towards the west

– All that matters is his conviction

• Whether it is or whether he could in no way affect the sentence’s truth or falsity

The Solution to Frege’s Problem About Identity

• For purposes of knowledge

– Sense is no less important than reference

• The morning star = the morning star &

• The morning star = the evening star

– Have the same reference & truth value, but their cognitive values are different

– They represent different judgments

Vacuous Names

• An important job for the notion of sense

– Is to explain the significance of

• Vacuous names

– For a name can have a sense

• Without having a reference

• If reference & meaning were the same

– It would then be meaningless to say that

• Santa Claus does not exist