Use Theory

1. Use Theory

2. recap

3. Motivation for Use Theory Most theories of meaning have trouble accounting for the meanings of logical terms like ‘and,’ ‘or,’ and ‘not.’ • Idea Theory: Can’t draw a picture of ‘and’; how does a picture of ‘A and B’ differ from a picture of ‘A or B’? • Causal Theory: the meanings of ‘and’ and ‘or’ are causally isolated.

4. Truth-Functions

5. Truth-Functions

6. Truth-Functions

7. Truth-Functions

8. Truth-Functions

9. A lot of logicians have thought: the meaning of ‘and’ is a truth-function (same for ‘or’ and ‘not’). The problem is to get a theory of meaning that will say that!

10. Inference Rules A and B B A and B A A,B A and B

11. Inference Rules A and B B A and B A A,B A and B If “B” is false, “A and B” must be false

12. Inference Rules A and B B A and B A A,B A and B If “A” is false, “A and B” must be false

13. Inference Rules A and B B A and B A A,B A and B If “A” and “B” are true, “A and B” must be true

14. A and B

15. Inference Rules The truth-functions are determined by the inference rules! Some philosophers are happy to stop there: the meaning is the truth-function, and the metasemantic theory is that the meanings of logical expressions are determined by the inference rules for those expressions.

16. Two Ways to Go Further • You could say that it’s not just logical expressions, but all words that have their meaning determined by the “inference rules” that govern them. • And you could say that the “inference rules” aren’t what determines the meaning, but that they are the meaning. This is what the Use Theory does say.

17. The Use Theory

18. The Use Theory and

19. The Use Theory and means AND

20. The Use Theory A and B B follows AND A and B A A, B A and B

21. The Use Theory A et B B follows ET A et B A A, B A et B

22. The Use Theory same concept AND ET

23. Summary of Principles • Words mean concepts, and “meaning” is univocal– it always means just “indication.” • For any word, all of its uses may be explained by a basic acceptance property: a regularity in the use of the word, that explains irregular uses as well. • Concepts are individuated by the basic acceptance properties of the words that express them.

24. Arguments for the use theory

25. PRO Argument 2: Explanation Premise: “What people say is due, in part, to what they mean.” Premise: “It is relatively unclear how any other sort of property of a word [besides use properties] would constrain its overall use.” Conclusion: Only the use theory can explain how what people say is due to what they mean.

26. Premise 2? I’m skeptical of premise 2 in this argument. Horwich says that what a word refers to can’t explain its use. Imagine I have a map of Central and on one part of it is written “Wing Lok Street.”

27. Premise 2? Why did the mapmaker use that name there? Quite sensibly, because the street drawn on the map corresponds to Wing Lok Street, and “Wing Lok Street” refers to Wing Lok Street.

28. Premise 2? How does a basic acceptance property provide a better explanation than that?

29. PRO Argument 3: Attribution When we judge that two words (in different languages or idiolects) mean the same thing, we check to see if their uses are appropriately similar.

30. Appropriate Similarity And what does ‘appropriate’ mean here? Horwich argues that it means differences in use are circumstantial– both words are still governed by the same basic acceptance property. He says we judge they mean differently when differences in use are more than merely circumstantial.

31. Theoretical Entities Redux This is certainly an empirical question. It does run Horwich into some potential trouble though (CON Argument 2: Holism). People with radically different theories (about electrons or whatever) will use words in radically different ways.

32. Radical Theory Difference

33. Theoretical Entities Redux Horwich can say that they are still talking about the same thing but only up until the point that their uses are governed by the same basic acceptance property. Again, whether this comports with intuition is an empirical matter.

34. PRO Argument 4 Premise 1: We are generally inclined to accept inferences from a sentence S containing word w, S(w), to the sentence S(v), when w and v are synonyms (have the same meaning).

35. PRO Argument 4 Premise 2: If the use theory is true, then w and v are synonyms = w and v’s uses are governed by the same basic acceptance property. Thus if w’s basic acceptance property leads me to accept S(w), v’s basic acceptance property, which is the same as w’s, will likewise lead me to accept S(v)

36. PRO Argument 4 Inference to the best explanation: Since no other theory of meaning explains these facts better than the use theory, the use theory is true.

37. Against Application as a ToM For example, Horwich argues that if the meaning of ‘groundhog’ is what it applies to, then to know the meaning is to know what it applies to.

38. Against Application as a ToM And to know the meaning of ‘woodchuck’ is to know what it applies to. But, he claims, you can know all this without knowing that ‘groundhog’ and ‘woodchuck’ apply to all the same things.

39. In Defense of Denotation Is that really true though? Many philosophers have held that the meaning of a sentence is its truth-conditions (and remember: truth is a notion belonging to the denotation relations). To know what a sentence means is to know the circumstances under which it is true.

40. In Defense of Denotation If S(w) and S(v) are true under the same circumstances, then shouldn’t we know that S(w) if and only if S(v), when we know their meanings?

41. In Defense of Horwich Well… not exactly. There are classic examples where sentences are true under the same circumstances, but not known to be so by people who understand them: • 2 + 2 = 4 if and only if Obama is president. • eiπ + 1 = 0 if and only if Obama is president.

42. PRO Argument 5: Implicit Definition An implicit definition is where we define a word or symbol by using the defined symbol in a context. Here’s an example:

43. Euclid’s Postulates 1. A straight line segment can be drawn joining any two points. 2. Any straight line segment can be extended indefinitely in a straight line. 3. Given any straight line segment, a circle can be drawn having the segment as radius and one endpoint as center.

44. Euclid’s Postulates 4. All right angles are congruent. 5. Given any straight line and a point not on it, there exists one and only one straight line which passes through that point and never intersects the first line, no matter how far they are extended.

45. PRO Argument 5: Implicit Definition Horwich argues that the use theory is needed to make sense of implicit definition. When people are given a set of axioms or postulates involving new terms, they accept them and use those postulates to decide what other sentences involving those terms to accept.

46. PRO Argument 5: Implicit Definition Thus the implicitly defining postulates wind up being the basic acceptance properties governing future use.

47. Implicit Definition? This argument rests quite a bit on the possibility of implicit definition. There’s some reason to think things don’t work this way.

48. Non-Euclidean Geometry In non-Euclidean geometry, lines don’t satisfy Euclid’s postulates. But that doesn’t make sense if Horwich is right: the things in non-Euclidean geometry aren’t lines.

49. PRO Argument 6: Translation Why is it that when I say, “I’d like some cheese” in America and “Je voudrais du fromage” in France, similar things happen in both countries? Here’s Horwich’s idea. I have this theory: If I say “I’d like some _____” in America, peons bring me some _____.

50. Further Theory In addition, I have this theory: If I say, “I’d like ----- _____” in America then peons bring me ----- _____. For example, If I say “I’d like ALL cheese,” then peons bring me ALL cheese.