In Defense of Physicalist Accounts of Consciousness

1. In Defense of Physicalist Accounts of Consciousness Ron Chrisley School of Cognitive & Computing Sciences, University of Sussex After October 1st: School of Computer Science, University of Birmingham Toward A Science of Consciousness 2001 Skövde, Sweden August 11, 2001 TSC 2001

2. Can we have ascienceofconsciousness? TSC 2001

3. Can we have ascienceofconsciousness? TSC 2001

4. Ö Can we have ascienceofconsciousness? TSC 2001

5. More specifically:Can we have aphysicalistscienceof consciousness? TSC 2001

6. Take-Home Message If we gain a better understanding of what science is, then we will have a better idea of whether particular scientific accounts of consciousness are possible I’ll show this by looking at particular case – even if you disagree with the details, you can still agree with the general point TSC 2001

7. Overview • Look at three influential arguments against the possibility of a physicalist account of consciousness: TSC 2001

8. Overview • Look at three influential arguments against the possibility of a physicalist account of consciousness: • Nagel: incompatibility of subjective and objective TSC 2001

9. Overview • Look at three influential arguments against the possibility of a physicalist account of consciousness: • Nagel: incompatibility of subjective and objective • Jackson: knowledge argument (feat. Mary) TSC 2001

10. Overview • Look at three influential arguments against the possibility of a physicalist account of consciousness: • Nagel: incompatibility of subjective and objective • Jackson: knowledge argument (feat. Mary) • Chalmers: lack of logical supervenience (zombie earth) TSC 2001

11. Overview • Show that these arguments only work on a particular and implausible view of science: TSC 2001

12. Overview • Show that these arguments only work on a particular and implausible view of science: • Objectivity as “the view from nowhere” TSC 2001

13. Overview • Show that these arguments only work on a particular and implausible view of science: • Objectivity as “the view from nowhere” • Science as non-experiential TSC 2001

14. Overview • Show that these arguments only work on a particular and implausible view of science: • Objectivity as “the view from nowhere” • Science as non-experiential • Explanations as logical deductions TSC 2001

15. Strategy/Caveats Will argue for the possibility of physicalist accounts of consciousness: TSC 2001

16. Strategy/Caveats Will argue for the possibility of physicalist accounts of consciousness: • By refuting three influential arguments against same TSC 2001

17. Strategy/Caveats Will argue for the possibility of physicalist accounts of consciousness: • By refuting three influential arguments against same • Not a direct argument; failure of the three arguments is compatible with the impossibility of physicalist accounts TSC 2001

18. Strategy/Caveats Will argue for the possibility of physicalist accounts of consciousness: • By refuting three influential arguments against same • Not a direct argument; failure of the three arguments is compatible with the impossibility of physicalist accounts • Will be brisk, leaving out detail, and assuming familiarity with the three arguments to be rejected TSC 2001

19. Defining terms • “Physicalist” TSC 2001

20. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative TSC 2001

21. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative • Roughly: business as usual TSC 2001

22. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative • Roughly: business as usual • “Account” TSC 2001

23. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative • Roughly: business as usual • “Account” • Scientific TSC 2001

24. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative • Roughly: business as usual • “Account” • Scientific • Where the action is TSC 2001

25. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative • Roughly: business as usual • “Account” • Scientific • Where the action is • “Consciousness” TSC 2001

26. Defining terms • “Physicalist” • Non-dualistic, ontologically conservative • Roughly: business as usual • “Account” • Scientific • Where the action is • “Consciousness” • Phenomenal awareness: “hard problem” TSC 2001

27. Nagel’s argument:Subjectivity vs objectivity • Consciousness is a subjective phenomenon TSC 2001

28. Nagel’s argument:Subjectivity vs objectivity • Consciousness is a subjective phenomenon • That is, consciousness is accessible only from a subjective point of view TSC 2001

29. Nagel’s argument:Subjectivity vs objectivity • Consciousness is a subjective phenomenon • That is, consciousness is accessible only from a subjective point of view • But scientific accounts should be objective TSC 2001

30. Nagel’s argument:Subjectivity vs objectivity • Consciousness is a subjective phenomenon • That is, consciousness is accessible only from a subjective point of view • But scientific accounts should be objective • Objective accounts are from “no point of view”, or a “God’s-eye view”: contain no subjectivity TSC 2001

31. Nagel’s argument:Subjectivity vs objectivity • Consciousness is a subjective phenomenon • That is, consciousness is accessible only from a subjective point of view • But scientific accounts should be objective • Objective accounts are from “no point of view”, or a “God’s-eye view”: contain no subjectivity • Thus, science cannot explain subjective consciousness TSC 2001

32. Rejecting “The view from nowhere” • Nagel’s mistake concerns the nature of objectivity TSC 2001

33. Rejecting “The view from nowhere” • Nagel’s mistake concerns the nature of objectivity • Not a God’s eye view, not a “perspectiveless perspective” TSC 2001

34. Rejecting “The view from nowhere” • Nagel’s mistake concerns the nature of objectivity • Not a God’s eye view, not a “perspectiveless perspective” • Rather, a way of negotiating human, perspective-bound views; “a view from anywhere” (Brian Cantwell Smith, On the Origin of Objects) TSC 2001

35. Rejecting “The view from nowhere” • Nagel’s mistake concerns the nature of objectivity • Not a God’s eye view, not a “perspectiveless perspective” • Rather, a way of negotiating human, perspective-bound views; “a view from anywhere” (Brian Cantwell Smith, On the Origin of Objects) • Thus, no incompatibility between objectivity and subjective experience TSC 2001

36. Jackson’s knowledge argument • Suppose there is a scientist, Mary, who has all the physical information about vision, but has never actually seen colour. TSC 2001

37. Jackson’s knowledge argument • Suppose there is a scientist, Mary, who has all the physical information about vision, but has never actually seen colour. • When she eventually does see, say, red, she learns something she didn’t know before: what it’s like to see red TSC 2001

38. Jackson’s knowledge argument • Suppose there is a scientist, Mary, who has all the physical information about vision, but has never actually seen colour. • When she eventually does see, say, red, she learns something she didn’t know before: what it’s like to see red • So physical information is not all the information about consciousness TSC 2001

39. Rejecting the non-experiential view of science • Jackson’s mistake is to assume that science is a set of propositions that can be written down and read, independently of experience TSC 2001

40. Rejecting the non-experiential view of science • Jackson’s mistake is to assume that science is a set of propositions that can be written down and read, independently of experience • Rather, science is an experiential activity, not just the “output” of that activity TSC 2001

41. Rejecting the non-experiential view of science • Jackson’s mistake is to assume that science is a set of propositions that can be written down and read, independently of experience • Rather, science is an experiential activity, not just the “output” of that activity • To be sure, text plays a big role in the activity of science, but so also does experience TSC 2001

42. Rejecting the non-experiential view of science • Jackson’s mistake is to assume that science is a set of propositions that can be written down and read, independently of experience • Rather, science is an experiential activity, not just the “output” of that activity • To be sure, text plays a big role in the activity of science, but so also does experience • Science does not aspire to provide an account of anything to anyone independently of their experience TSC 2001

43. What to do about Mary? • Mary may have all the “physical information”, but does not know everything that science knows about vision TSC 2001

44. What to do about Mary? • Mary may have all the “physical information”, but does not know everything that science knows about vision • Thus, the fact that she learns something does not indicate some limitation of science TSC 2001

45. What to do about Mary? • Mary may have all the “physical information”, but does not know everything that science knows about vision • Thus, the fact that she learns something does not indicate some limitation of science • Science presupposes that one already knows what is trying to be explained TSC 2001

46. What to do about Mary? • Mary may have all the “physical information”, but does not know everything that science knows about vision • Thus, the fact that she learns something does not indicate some limitation of science • Science presupposes that one already knows what is trying to be explained • It does not atempt to make this intelligible for those for whom the problem does not arise TSC 2001

47. Chalmers’ argument:the possibility of Zombie Earth • Scientific explanations must show how the lower-level facts logically entail what is to be explained TSC 2001

48. Chalmers’ argument:the possibility of Zombie Earth • Scientific explanations must show how the lower-level facts logically entail what is to be explained • We can imagine a Zombie Earth, physically identical to Earth, but with no consciousness at all TSC 2001

49. Chalmers’ argument:the possibility of Zombie Earth • Scientific explanations must show how the lower-level facts logically entail what is to be explained • We can imagine a Zombie Earth, physically identical to Earth, but with no consciousness at all • So consciousness is not logically entailed by physical facts TSC 2001

50. Chalmers’ argument:the possibility of Zombie Earth • Scientific explanations must show how the lower-level facts logically entail what is to be explained • We can imagine a Zombie Earth, physically identical to Earth, but with no consciousness at all • So consciousness is not logically entailed by physical facts • So there cannot be a physicalist explanation of consciousness TSC 2001