Philosophy E156: Philosophy of Mind

1. Philosophy E156: Philosophy of Mind Week 12: Dennett’s Multiple Drafts Model and the Case Against Filling In

2. Cartesian Materalism • Descartes believed not only in dualism, that we are made up of both brain and soul, but that there was a point in the brain where everything came together before it was sent across a psychophysical bridge into the soul • He located that point in the pineal gland, located between the two hemispheres • Dennett ridicules the non-dualist vestige of such a view as “Cartesian materialism” (CE, p. 107): • “the view you arrive at when you discard Descartes’s dualism but fail to discard the imagery of a central (but material) Theater where ‘it all comes together’”

4. The Cartesian Theater • “The Cartesian Theater is a metaphorical picture of how conscious experience must sit in the brain. • “It seems at first to be an innocuous extrapolation of the familiar and undeniable fact that for everyday, macroscopic time intervals, we can indeed order events into the two categories ‘not yet observed’ and ‘already observed.’ • “We do this by locating the observer at a point and plotting the motions of the vehicles of information relative to that point.”

6. Problem with the Cartesian Theater Metaphor • “But when we try to extend this method to explain phenomena involving very short time intervals, we encounter a logical difficulty: • If the ‘point’ of view of the observer must be smeared over a rather large volume in the observer’s brain, the observer’s own subjective sense of sequence and simultaneity must be determined by something other than ‘order of arrival,’ since order of arrival is incompletely defined until the relevant destination is specified.”

7. Three Puzzle Cases • Nelson Goodman’s & Paul Kolers’ “color phi” experiment • Geldard & Sherrick’s “cutaneous rabbit” experiment • Benjamin Libet’s “backward referral in time” cases

8. Phi Phenomenon • http://upload.wikimedia.org/wikipedia/commons/6/6e/Lilac-Chaser.gif

9. Color Phi Demonstration • http://www.philosophy.uncc.edu/faculty/phi/Phi_Color2.html

10. Color Phi Demonstration • http://highered.mcgraw-hill.com/sites/0070579431/student_view0/chapter8/phi_phenomenon_activity.html

11. Color Phi Penomenon

12. The Cutaneous Rabbit Illusion • http://video.search.yahoo.com/search/video;_ylt=A0geuqHVbYJSFmoAWkpXNyoA?p=Cutaneous+rabbit+illusion&fr=yfp-t-600&fr2=piv-web

13. Dennett’s Question • “Now, at first one feels like asking how did the brain know that after the five taps on the wrist, there were going to be some taps near the elbow?” (CE, p. 143)

14. Libet’s Experimental Results • Benjamin Libet ran experiments on willing subjects during brain surgery • He discovered a 500-millisec delay between the physical prodding of a part of the brain and the conscious awareness associated with that brain part • Normal stimulation of the brain by stimulation of the skin is faster – as required if anything is achievable in a timely way • Libet explained the discrepancy by positing “backward referral in time” – mental causation begins in unconsciousness & consciousness backdates experience to seem as if it was conscious from the start

15. Eccles Claims Libet’s Results Are Inconsistent with Physicalism • Eccles: “This antedating procedure does not seem to be explicable by any neurophysiological process. Presumably it is a strategy that has been learnt by the self-conscious mind…. The antedating sensory experience is attributable to the ability of the self-conscious mind to make slight temporal adjustments, i.e., to play tricks with time.”

16. Penrose Claims Libet’s Results Are Inconsistent with Ordinary Physicalism • Penrose: “[W]e seem to be driven to the conclusion that in any action in which an external stimulus leads to a consciously controlled response, a time delay of some one and one-half seconds would seem to be needed before that response can occur. For awareness would not even take place until half a second has passed; and if that awareness is to be put to use, then the apparently sluggish machinery of free will would then have to be brought into play, with perhaps another second's delay.... [I]f, in some manifestation of consciousness, classical reasoning about the temporal ordering of events leads us to a contradictory conclusion, then this is a strong indication that quantum actions are indeed at work!”

17. The Multiple Drafts Model • Dennett tries to explain these effects by positing parallel processing in the brain of sensory inputs that involves constant interpretation and revision, but only a single detection and discrimination, and no re-presentation.

20. Julesz Random-Dot Stereogram To construct a random-dot stereogram, you first place a bunch of dots randomly in an image. Then make two copies of it.  In one copy shift a central square region to the left and in the other copy shift the same central square region to the right. This leaves holes in each of the images (left over from where the square shifted from). Fill the holes with new random dots.  Why do you see it in 3D?  The shift mimics differences which ordinarily exist between the views of genuine 3D objects. The extra dots (X and Y above) correspond to those parts of the background that one eye can see, but which are occluded from the view of the other eye by the foreground square. (http://www.cns.nyu.edu/~david/courses/perception/lecturenotes/depth/depth-size.html)

25. Orwellian & Stalinesque Falsifications of Experience • On reflection, we should – and often do – recognize possibility of falsification in constructing experience • Dennett takes this lesson from Descartes, although I say Descartes himself recognizes this possibility • Two kinds of falsification are possible • pre-experiential • post-experiential • Pre-experiential falsification Dennett calls “Stalinesque,” because of Stalin’s show trials • Post-experiential falsification Dennett calls “Orwellian,” because of Orwell’s Ministry of Truth

26. Orwellian Revisions

27. Orwellian Revisions • The paradigm Orwellian device is the construction of false memories

28. Orwellian Revisions • The paradigm Orwellian device is the construction of false memories • Dennett tells a story about your seeing a long-haired woman but one second later having the experience contaminated by a memory of a short-haired woman with glasses

30. Orwellian Revisions • The paradigm Orwellian device is the construction of false memories • Dennett tells a story about your seeing a long-haired woman but one second later having the experience contaminated by a memory of a short-haired woman with glasses

31. Orwellian Revisions • The paradigm Orwellian device is the construction of false memories • Dennett tells a story about your seeing a long-haired woman but one second later having the experience contaminated by a memory of a short-haired woman with glasses • This causes you to falsely report having seen a long-haired woman with glasses

32. Orwellian Revisions • The paradigm Orwellian device is the construction of false memories • Dennett tells a story about your seeing a long-haired woman but one second later having the experience contaminated by a memory of a short-haired woman with glasses • This causes you to falsely report having seen a long-haired woman with glasses • An “Orwellian revision” of your experience

33. Stalinesque Falsifications

34. Stalinesque Falsifications • The paradigm Stalinesque device is hallucination

35. Stalinesque Falsifications • The paradigm Stalinesque device is hallucination • Imagine that your having the memory of the short-haired woman with glasses causes you to hallucinate the eyeglasses onto the long-haired woman

41. Stalinesque Falsifications • The paradigm Stalinesque device is hallucination • Imagine that your having the memory of the short-haired woman with glasses causes you to hallucinate the eyeglasses onto the long-haired woman

42. Stalinesque Falsifications • The paradigm Stalinesque device is hallucination • Imagine that your having the memory of the short-haired woman with glasses causes you to hallucinate the eyeglasses onto the long-haired woman • Unlike the first case, it is this hallucination which causes you to falsely report having seen a long-haired woman with glasses

43. Stalinesque Falsifications • The paradigm Stalinesque device is hallucination • Imagine that your having the memory of the short-haired woman with glasses causes you to hallucinate the eyeglasses onto the long-haired woman • Unlike the first case, it is this hallucination which causes you to falsely report having seen a long-haired woman with glasses • “Stalinesque falsification” of your experience

44. No Distinction • In some cases, Dennett argues, there might be no distinction between the Orwellian and the Stalinesque falsification • We have the idea that there must be, he argues, because we have the idea that there must be an “actual conscious experience” even if we are unable to report it • This is just the idea of the Cartesian Theater • There is “no privileged finish line,” he says

45. Orwellian & Stalinesque Interpretations of Color Phi

47. Orwellian & Stalinesque Interpretations of Color Phi • Hypothesis of a Stalinesque mechanism:

48. Orwellian & Stalinesque Interpretations of Color Phi • Hypothesis of a Stalinesque mechanism: • “In the brain’s editing room, located before consciousness, there is a delay, a loop of slack like the tape delay used in broadcasts of ‘live’ programs, which gives the censors in the control room a few seconds to bleep out obscenities before broadcasting the signal” (CE, p. 120)

49. Orwellian & Stalinesque Interpretations of Color Phi • Hypothesis of a Stalinesque mechanism: • “In the brain’s editing room, located before consciousness, there is a delay, a loop of slack like the tape delay used in broadcasts of ‘live’ programs, which gives the censors in the control room a few seconds to bleep out obscenities before broadcasting the signal” (CE, p. 120) • Hypothesis of an Orwellian mechanism:

50. Orwellian & Stalinesque Interpretations of Color Phi • Hypothesis of a Stalinesque mechanism: • “In the brain’s editing room, located before consciousness, there is a delay, a loop of slack like the tape delay used in broadcasts of ‘live’ programs, which gives the censors in the control room a few seconds to bleep out obscenities before broadcasting the signal” (CE, p. 120) • Hypothesis of an Orwellian mechanism: • “shortly after the consciousness of the first spot and the second spot (with no illusion of apparent motion at all), a revisionist historian of sorts, in the brain’s memory-library receiving station, notices that the unvarnished history in this instance doesn’t make enough sense, so he interprets the brute events, red-followed-by-green, by making up a narrative about the intervening passage, complete with mid-course color change, and installs this history….” (CE, pp. 120-1)