Problems for the Idea Theory - PowerPoint Presentation

Slide1

Problems for the Idea TheorySlide2

Review from last timeSlide3

Metasemantics

Theories of Meaning

The Conformal Theory

The Idea Theory

The Resemblance Theory

BerkeleySlide4

General terms/

Abstract ideasSlide5

Locke on General Terms

“

It is not enough for the perfection of language, that sounds can be made signs of ideas, unless those signs can be so made use of as to comprehend several particular

things…”Slide6

Locke on General Terms

“…for

the multiplication of words would have perplexed their use, had every particular thing need of a distinct name to be signified

by…”Slide7

Locke on General Terms

“To

remedy this inconvenience, language had yet a further improvement in the use of

general terms

, whereby one word was made to mark a multitude of particular existences.”Slide8

Particular Terms

LockeSlide9

General Terms

DogSlide10

Abstract Ideas

If we accept the idea theory, then, we have to accept that there are “abstract ideas”– not mental pictures of a particular person, but mental pictures that resemble equally a group of things.

These abstract ideas are the meanings of

general terms.Slide11

Berkeley vs. Abstract Ideas

Berkeley, however, argues that abstract ideas are impossible. The abstract idea of a man is supposed to apply equally to a tall man and a short man; a black man and a white man; a skinny man and a fat man; well-dressed man and a pauper, etc. But no picture resembles equally all such men, as any picture of a man depicts him as either skinny or fat, but not both and not neither. Slide12

Berkeley

Again, this didn’t lead Berkeley to reject the idea theory, only to (once again) place a severe limit on what we can have ideas of.

Just as we can’t have ideas of non-ideas (because non-ideas can’t resemble ideas) we can’t have ideas of abstract things, because mental pictures are always determinate and never abstract (like regular pictures).Slide13

The tribunal of experienceSlide14

Hume: Impressions and Ideas

David Hume took Berkeley’s style of austere empiricism to its logical extreme.

Hume makes a distinction that wasn’t made by Locke and Berkeley between impressions and ideas. Impressions are sensations or perceptions or sense experiences. Things like seeing red or feeling pain. The idea of red is not the same thing as seeing red though: for Hume, all (simple) ideas are “copies” of impressions.Slide15

The Tribunal of Experience

Hume then proposes the tribunal of experience. For each supposed idea, we ask:

Is it copied from an impression? If so, which one? [No answer? Go to (d).]

If not, is it a complex idea, built out of simpler ones?

If so, repeat (a) and (b) for each of its parts.

If not, it’s not really an idea at all!Slide16

Hume vs. Causation

Hume notoriously targeted causation for the tribunal of experience. Imagine the following sequence of events (that is, have the following sequence of ideas in your head): first you have an idea of ball A headed toward ball B. Then A hits B and causes B to move away. Got it? OK, now imagine this other sequence of events: A is moving toward B, A and B touch, and B moves away on its own (not because A caused it).Slide17

Hume vs. Causation

What’s the difference here? Hume argued that there wasn’t one. You couldn’t

see

one event causing another, and since all ideas were copies of impressions (for Hume), you couldn’t have an idea of one event causing another. Slide18

Other Imperceptibles

There were some other problems with the idea theory involving

unobservables

. How is your idea of a black hole or an electron anything like those things? Even more straightforwardly, how is your idea of (for example) Moses anything like Moses (there’s no ancient statues or other representations of him)? But it seems we do have an idea of Moses, at least in the sense that we can think about him.Slide19

Concepts vs. propositionsSlide20

Problems for Resemblance Theory

Can’t distinguish concepts and propositions.

Resemblance is an equivalence relation, representation is not.

Resemblance is in some ways more and in some ways less determinate than representation.

Even photos and paintings don’t represent what they resemble.Slide21

Concepts

Concepts are representations of things or qualities: so I can have a concept of Obama, or a concept of red, or a concept of a horse, or a concept of a concept.

Importantly, concepts are

not truth-evaluable

. My concept of red isn’t true, and it isn’t false either. It might be more or less accurate.Slide22

Propositions

We can say that when I

think of

a thing, or

think about

a thing, then I am entertaining a concept.

However, when I

think that

such-and-such, I am entertaining a proposition. Slide23

Propositions

For example, I can think that Obama is the US president, or think that grass is red, or think that the concept of a horse is not a concept.

Propositions

are

truth-evaluable: when I think that grass is red, my thought is false. (Not so when I just think

of

red.)Slide24

The idea theory seems to have trouble distinguishing concepts and propositions.

According to the idea theory, thought is having ideas, and ideas are like mental pictures. Are mental pictures truth-evaluable? If they are, then concepts aren’t ideas. If they aren’t, then propositions aren’t ideas. Slide25

Equivalence RelationsSlide26

Resemblance as an Equivalence Relation

Resemblance, like identity, is an equivalence relation, meaning it’s reflexive, symmetric, and transitive:

Reflexive

: for all X, X resembles X. (Everything resembles itself.)

Symmetric

: for all X and Y, if X resembles Y, then Y resembles X.

Transitive

: for all X, Y, and Z, if X resembles Y and Y resembles Z, then X resembles Z.Slide27

Problem for the idea theory: resemblance is an equivalence relation, but representation is not. Therefore representation ≠ resemblance.Slide28

1. Representation is Not Reflexive

You can have a representation that represents itself (for example, a map of Hong Kong that includes the map’s location), but most representations don’t represent themselves.

You can have a painting of a horse, that is not a painting of a painting of a horse (not a painting of itself).Slide29

2. Representation is Not Symmetric

Most of what gets represented is not representational. My thoughts represent lakes and rivers and trees, but lakes and rivers and trees don’t represent my thoughts.

And even when I do represent representations (when I think about a painting, say), usually they don’t represent me or my thoughts.Slide30

3. Representation is not Transitive

The directory at the museum might represent the location of a certain Picasso painting. That painting could represent a horse. But the directory doesn’t represent any horses, it only represents paintings.Slide31

We could try a strategy similar to Aquinas’ in dealing with the reflexivity problem for the conformal theory. [Does that work?]Slide32

Indeterminacy and Error

Another class of problems for resemblance theories of representation involve indeterminacy and error.Slide33

Wittgenstein’s Man on the Hill

“A picture which corresponds to a man walking up a hill forward corresponds equally, and in the same way, to a man sliding down the hill backward.”

-- Philosophical InvestigationsSlide34

Wittgenstein’s Man on the Hill

“

Perhaps a Martian would describe the picture

[as the man sliding down].

I do not need to explain why

we

do not describe it

so.”

Representation can be

more determinate

than resemblance.Slide35

Twins

Suppose

you met a woman last night and I met her twin. You and I both have memories (mental representations) of the women we met, and let’s suppose those mental images are identical in every

respect.Slide36

Twins

Here, even though the representational vehicles are the same, and thus resemble the exact same things, the representational contents are different.Slide37

Error

Consider a revised version of the twins case: you and I separately meet each of two twins. They are exactly alike except that the twin you meet has a scar on her left cheek and mine has no scar. Slide38

Error

However, the next day I falsely remember my twin as having a scar on her left cheek. Then the resemblance theory says

my memory is about the twin you met.

Someone I’ve never met in my entire life

!Slide39

Massive Error

Imagine that I have a pen pal whom I’ve never met, or seen a picture of. Over the course of our correspondence, I develop an elaborate mental image of her: what color her hair is, how big her nose is, etc. Suppose that my mental image is completely wrong and doesn’t resemble my pen pal at all. Slide40

Massive Error

On the resemblance view, it would seem that I was incapable of thinking about her, for example, I couldn’t think: “Oh, here’s another letter from my pen pal!”Slide41

Indeterminacy of Resemblance

In

both the man-on-the-hill case and the twin case, what we have is one representation that exactly resembles two distinct things (man going up vs. man going down, twin #1 vs. twin #2). Slide42

Indeterminacy of Resemblance

If

representation = resemblance, then my memory (for example) should represent both twins equally. But I only have a memory

of

one of them; my memory represents only one of them.Slide43

Error

Consider a revised version of the twins case: you and I separately meet each of two twins. They are exactly alike except that the twin you meet has a scar on her left cheek and mine has no scar. However, the next day I falsely remember my twin as having a scar on her left cheek. Then the resemblance theory says my memory is about the twin you met (someone I’ve never met in my entire life).Slide44

Conceptual Competence

One direction for a solution to the problem of error is to say that my idea of my twin or my pen pal is only a “partial” idea or is an “incompletely grasped” idea or something like that. Slide45

Conceptual Competence

That may be true, but this doesn’t really resolve the problem. Why is the idea– partial or incomplete as it is– an idea

of

my pen pal, rather than of someone else whom it more closely resembles, or of a mere fiction?Slide46
Slide47

Fodor vs. the Image Theory

Fodor holds that thought happens in a language (“the language of thought”) rather than in images– the ideas of the idea theorist. One argument goes like this: you can see a Necker cube in two different ways. There’s one picture that corresponds to two ideas. But if ideas are just mental pictures, what two

different

mental pictures correspond to the two different ways you can see the one physical picture?Slide48
Slide49

Seeing vs. Seeing-as

What the Necker cube example suggests is a more general problem. You can look at the Fischer cow and not see that it is a cow. When you see the picture

as

a cow, your perception changes. But if your idea of the picture is just a copy of that picture in your head, what about it changes such that once it was just squiggles and then it’s a cow?Slide50

Fodor vs. the Image Theory

Another argument is that the idea theorist doesn’t have a good story about my thought that I am NOT wearing a red shirt. Is it a picture of me wearing a blue shirt? Or a green one? What if I’m just thinking that I’m NOT wearing a red one, but not thinking of what color shirt I am wearing? Notice how “No smoking” signs have to resort to non-pictorial symbols. You can’t just have a sign where someone isn’t smoking.Slide51

Perhaps the biggest problem for the idea theory is that in most cases where x resembles y, x does not represent y.

Two cows for instance might resemble each other much more than our ideas, paintings, or photographs resemble them. Yet we have no inclination to say that the cows represent each other.Slide52

Hilary Putnam points out an interesting case. Imagine two lines in the sand. One has been drawn by a human with the intention of tracing the figure of Winston Churchill, and it resembles him (or his figure) a lot. The other has been traced by an ant just wandering aimlessly in the sand. But imagine that the ant’s line is identical to the human’s. We think the human-drawing represents Churchill, but the ant-line doesn’t.Slide53

This suggests that

drawings, paintings, and so forth don’t represent things by resembling them

. They represent things on the basis of our intentions.

But the entire motivation of the idea theory was to model ideas on drawings and paintings.

Those

things represent by resembling, and that’s how ideas were supposed to work as well.Slide54

summarySlide55

The Idea Theory

The idea theory is an attempt to answer the question: why do words mean what they do, rather than something else, or nothing at all. It’s a “metasemantic” theory.

According to the theory, words are associated arbitrarily and conventionally with ideas, which are construed as something like little colored pictures in the mind.Slide56

Representation as Resemblance

This is not the whole story, because it doesn’t explain why the word ‘dog’

is true of

dogs. This is a question about meaning (“is true of” is a semantic relation).

So the idea theory further says that ‘dog’ is true of dogs, because the idea associated with ‘dog’ most closely resembles dogs (as opposed to cats, or nothing at all). Slide57

The Idea Theory in History

The idea theory was influential, especially among the British Empiricists of the 17

th

and 18

th

Centuries. Philosophers were willing to abandon abstract ideas, ideas about cause and effect, and some even maintained that thought about an external world was impossible– that since only ideas resemble ideas, what we think about when we think about tables and chairs and mountains are ideas.Slide58

Problems

Eventually, however, the idea theory came into ill-repute. There were lots of reasons, and we discussed a few:

There’s a distinction between concepts and propositions that is blurred on the idea theory.

Resemblance is an equivalence relation, representation is not. So representation can’t be identical to resemblance.Slide59

Problems

Representation can be more determinate than resemblance: we can think of a man going up a hill, even if the image equally applies to a man sliding down; we can think of a Necker cube with one side to us, even if the image equally applies to a cube with the other side to us.

In general, resembling things simply don’t represent one another.