Philosophy of Mind (Continued)

1. Philosophy of Mind (Continued) • On Monday: • Dualism • Logical Behaviorism • Methodological behaviorism • Today: • The Mind/Brain Identity Theory • Functionalism

2. The Mind/Brain Identity Theory Water = H2O Mind = Brain

3. The Mind/Brain Identity Theory Water = H2O Mind = Brain This is a conclusion reached by science. You can’t tell what the mind is just by thinking really hard, as Descartes’ and Ryle’s arguments assumed.

4. The Mind/Brain Identity Theory Materialism: All physical events have physical explanations, including human behavior.

5. The Materialist Slogan: No mental difference without a physical difference

6. The Materialist Slogan: No mental difference without a physical difference Materialism: There must be some physical difference between someone who loves jazz and someone who hates jazz. Dualism: Someone who loves jazz could be physically identical to someone who hates jazz.

7. The Materialist Slogan: No mental difference without a physical difference According to Identity Theory: Dualism gets more and more implausible as we learn more about the nervous system.

8. The Materialist Slogan: No mental difference without a physical difference According to Identity Theory: Dualism gets more and more implausible as we learn more about the nervous system. Dualism made sense before we had any way of knowing which physical differences correlated with loving jazz. Now we know.

10. 2,000 years ago, Lucretius was a materialist before it was cool. He believed that the mind is part of the body, so when the body dies, the mind does too. But Lucretius thought the mind was more like a hormone—a chemical substance.

11. 2,000 years ago, Lucretius was a materialist before it was cool. He believed that the mind is part of the body, so when the body dies, the mind does too. But Lucretius thought the mind was more like a hormone—a chemical substance. Since then, the materialist account of the mind has gotten much better.

12. In the same manner, the materialist account of lightning has also improved. In Lucretius’s time, many seriously believed that lightning was made by Zeus. This was not just a cute story.

13. In the same manner, the materialist account of lightning has also improved. In Lucretius’s time, many seriously believed that lightning was made by Zeus. This was not just a cute story. At the time, this was literally the best explanation for lightning and thunder.

14. According to Identity Theory: The materialist account of the mind has gotten a lot better, just as the materialist account of lightning has gotten a lot better.

15. According to Identity Theory: The materialist account of the mind has gotten a lot better, just as the materialist account of lightning has gotten a lot better. Indeed, materialism is now the best explanation for both kinds of events.

16. Like Lucretius, we may not know exactly which physical event correlates with each and every mental event, but we can safely conclude that some physical event correlates with each and every mental event.

17. Like Lucretius, we may not know exactly which physical event correlates with each and every mental event, but we can safely conclude that some physical event correlates with each and every mental event. Identity between mind and brain is offered as the best explanation for these correlations.

18. The best explanation for correlations between mental events and neurological events is identity:

19. The best explanation for correlations between mental events and neurological events is identity: • Why is activity in a specific part of the brain always correlated with the enjoyment of jazz? • Because that’s what it is to enjoy jazz: activity in that part of the brain just is the enjoyment of jazz.

20. The best explanation for correlations between mental events and neurological events is identity: • Why is activity in a specific part of the brain always correlated with the enjoyment of jazz? • Because that’s what it is to enjoy jazz: activity in that part of the brain just is the enjoyment of jazz.

21. Do you agree with this? • activity in that part of the brain just is the enjoyment of jazz.

22. According to Identity Theory: Dualism is likeVitalism. Both theories posit some special substance as the best explanation for something, but we can now explain those same observations without positing that substance.

23. Vitalism: There is a physical substance—a “vital fluid”—found only in living things. It is the best explanation for what living things all share, and for the differences between living and non-living things.

24. Vitalism: There is a physical substance—a “vital fluid”—found only in living things. It is the best explanation for what living things all share, and for the differences between living and non-living things. Dualism: There is a non-physical substance—a “soul”—found only in humans. It is the best explanation for mental events.

25. Vitalism posits a physical substance, while Dualism posits non-physical substance.

26. Vitalism posits a physical substance, while Dualism posits non-physical substance. Still, Identity Theory says, both posits are superfluous.

27. Identity Theory: The concept of a soul does no explanatory work. (Like the concept of “vital fluid”)

28. Identity Theory: The concept of a soul does no explanatory work. (Like the concept of “vital fluid”) We need a materialist theory anyway, to explain physical things. This same theory can now explain everything Dualism was supposed to explain, but without positing any special substances.

29. Identity Theory: The materialist theory of the mind is a better explanation for mental events than dualism.

30. Identity Theory: The materialist theory of the mind is a better explanation for mental events than dualism. What makes it better?

31. Identity Theory: The materialist theory of the mind is a better explanation for mental events than dualism. What makes it better? Parsimony.

32. We need a materialist theory anyway. • We need to explain physical phenomena regardless of what we say about mental phenomena. If this same theory can also explain all mental phenomena, then why bring in some different, additional theory to explain those phenomena?

33. Materialism explains both physical phenomena and mental phenomena, in one unified theory. Dualism only explains mental phenomena.

34. Materialism explains both physical phenomena and mental phenomena, in one unified theory. Dualism only explains mental phenomena. All else being equal, a theory that both explains and unifies provides a better explanation than one that just explains, without unifying.

35. Materialism explains both physical phenomena and mental phenomena, in one unified theory. Dualism only explains mental phenomena. All else being equal, a theory that both explains and unifies provides a better explanation than one that just explains, without unifying. Thus, materialism provides a better explanation for mental events than dualism.

36. Materialism explains both physical phenomena and mental phenomena, in one unified theory. Dualism only explains mental phenomena. All else being equal, a theory that both explains and unifies provides a better explanation than one that just explains, without unifying. ??? Thus, materialism provides a better explanation for mental events than dualism.

37. In Groups: Provide support for this premise. Why is a unifying theory better than a non-unifying theory? All else being equal, a theory that both explains and unifies provides a better explanation than one that just explains, without unifying. ???

38. By definition, non-unified theories employ novel concepts, which can’t be defined in terms of concepts we are already committed to.

39. By definition, non-unified theories employ novel concepts, which can’t be defined in terms of concepts we are already committed to. The Principle of Parsimony Only posit novel concepts when you really have to, because your existing concepts can’t do the job.

40. According to Identity Theory, existing concepts can do the job. The Principle of Parsimony Only posit novel concepts when you really have to, because your existing concepts can’t do the job.

41. In Groups: • Do you agree that we should only posit novel concepts when our existing concepts prove inadequate? • Are parsimonious theories more likely to be true, or is parsimony good for some other reason? • (Recall the justification of induction...)

42. Functionalism

43. Functionalism Functionalism shares the Identity Theory’s commitment to materialism, and its rejection of dualism. However, it also finds problems with the Identity Theory.

44. Functionalism Functionalism agrees with Identity Theory that every token mental state is identical with some token brain state. But it disagrees that every type of mental state is identical with some type of brain state. What does this mean?

45. Tokens vs. Types • Tokens: particular, specific, concrete instances. • Example: the particular instance of redness displayed by a particular apple • Types: general kinds, or properties, which may take many different instances. • Example: the property of being red in general.

46. Tokens vs. Types • Tokens: particular, specific, concrete instances. • My homesickness, when I was at summer camp at age 10, is a token mental state. • Types: general kinds; properties that may have many different instances. • Homesickness in general, across all particular instances, is a mental type.

47. Functionalism agrees that token mental states are identical with token brain states. • My homesickness, when I was at summer camp at age 10, was identical with a certain state of my brain at the time.

48. Functionalism agrees that token mental states are identical with token brain states. • My homesickness, when I was at summer camp at age 10, was identical with a certain state of my brain at the time. • But it denies that types of mental state are identical with types of brain state. • Homesickness in general is not identical with any one type of brain state.

49. According to Functionalism: Psychological types, or properties, can be realized in multiple ways.

50. According to Functionalism: Psychological types, or properties, can be realized in multiple ways. Multiple Realizabilitysounds complicated, but it’s very simple. It just means that a property or type can be instantiated in physically different ways. • A wooden spoon and a metal spoon are physically different, but they’re still instances of the same type: spoon.