Theories of Mental Representation

1. Theories of Mental Representation Part I

2. Vehicle vs. Content Small [horse picture] [Small horse] picture

3. Vehicle vs. Content Representational vehicles are the things that represent (we can just call them representations: words, maps, photos, beliefs. The representational content of a representation is what it represents/ what it means.

4. Metasemantics Since most things don’t have representational content, and only a few things do, it’s reasonable to ask: why do things like maps, sentences, and thoughts have contentand rivers, lakes, and trees have no content?

5. Metasemantics Why is a map of Hong Kong a map of Hong Kong, rather than (say) a map of Kuala Lumpur? Whydo representationalthings have the contents they do rather than some other content?

6. Metasemantics “Metasemantics” (metaphysical semantics, the metaphysics of meanings) is the part of philosophy of language that tries to answer the question: “Why [in virtue of what] do representations have the contents they do, rather than some other content, or no contentat all?”

7. The conformal theory

8. Aristotle Aristotle (384-322 BCE) is in the running for “greatest Western philosopher” and he’s usually in everyone’s top 5 at least. According to Aristotle, substances are composed of matter + form.

9. Aristotle on Hylomorphism Example: a house is a substance. The matter of the house is the bricks, cement, plaster, wood, and so forth. But the house is not just the bricks and cement, etc. It is those bricks, cement, plaster, etc. arranged in a certain way: with a certain form.

10. The Conformal Theory of Representation Aristotle held an obscure doctrine of the identity of the knower with the known. When I think of a house, for instance, my soul (i.e. my matter) takes on the form of a house. Thus, even though I (me, my soul, my matter) am distinct from a house (its matter), I represent the house because it and my soul have literally the same form (the form of a house).

11. Conformal Theory Represents

12. Aquinas and the Conformal Theory Aristotle’s greatest medieval follower, St. Thomas Aquinas (1225-1274 CE), tried to deal with a problem in the conformal theory.

13. Problem for Conformal Theory Represents???

14. Intentional Presence The solution Aquinas proposed wasthat the house-form was not “really” present in me, it was only “spiritually” present. Spiritually present forms represent really present ones, but not vice versa. (Incidentally, this is also the explanation for why even though I have the form of a house, I don’t look anything like a house.)

15. Conformal Theory Spiritual Form Real Form Represents

16. The Idea Theory The addition of “spiritual forms” to regular forms presaged what would become the dominant view of mental representations: the idea theory.

17. Idea theory

18. The Nature of Ideas According to Locke, ideas are “the pictures drawn in our minds” (Essay, II.x.5).

19. The Nature of Ideas An idea of a horse, then, is very much like a picture, image, or painting of a horse. Compare Hume: “By ideas I mean the faint images of [perceptions] in thinking and reasoning” (Treatise, I.i.1).

20. Idea Theory Dagger Mind Idea of a Dagger

21. Indirect Realism The idea theory is a variety of “indirect realism.” What you directly see are mental entities (for example, ideas). You only indirectly see the real things that the ideas represent.

22. Resemblance Theory According to the resemblance theory of representation, ideas represent things by resembling them– sort of like how painting works. The resemblance theory is thus a theory of what it is in virtue of which ideas have the contents they have: the ideas resemble the contents.

23. Idea Theory Resembles Sees Dagger Mind Idea of a Dagger

24. Corpuscularianism In the 17th Century, corpuscularianim was the dominant scientific worldview. It held that all physical things are made of tiny little things called “corpuscles.” The theory was very similar to Greek atomism, with the exception that atoms couldn’t be divided and corpuscles (in theory) could.

25. Corpuscularianism Part of the theory held that corpuscles only had shape, size, solidity, and motion. They did not have color, taste, texture, smell, or heat, though they could cause us to experience these things by exciting our sense organs.

26. Idea Theory Partly Resembles Sees Dog Mind Idea of a Dog

27. Problems for the idea theory

28. 4. Problems for the resemblancetheory

29. 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.

30. 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.

31. 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.

32. 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.)

33. 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.

34. Equivalence Relations

35. 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.

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

37. 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).

38. 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.

39. 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.

40. Indeterminacy and Error Another class of problems for resemblance theories of representation involve indeterminacy and error.

41. 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 Investigations

42. 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.

43. 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.

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

45. 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.

46. 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!

47. 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.

48. 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!”

49. 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.

50. 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?