Notes towards a Computational Theory of Consciousness

1. Notes towards aComputational Theoryof Consciousness William J. Rapaport Department of Computer Science & Engineering, Department of Philosophy, Department of Linguistics, and Center for Cognitive Science rapaport@cse.buffalo.edu http://www.cse.buffalo.edu/~rapaport

2. 2 (or 3) Questions for a Computational Theory of Consciousness • Could a computational cognitive agent“be conscious”? • I think so • But it depends on what’s meant by “conscious” 1.5. If so, how would we build one? • Answer depends on “psychological” theories of consciousness • How would we know? • We wouldn’t… • …any more (or less) than we know about humans!

3. And What about Qualia? • “What are qualia?”≈ “What are numbers?” ≈? “What is the base case of a recursion?” • Problem of role of qualia in theories of consciousness ≈Problem of mathematical structuralism

4. What Is Consciousness? • What is ‘consciousness’? From the OED: • L. con- together + sci- knowing;knowing something with others,knowing in oneself, privy to • 1601 (Ben Jonson): Attributed to inanimate things as privy to, sharing in, or witnesses of human actions or secrets • 1620: having the witness of one’s own judgment or feelings, knowing within oneself • 1651 (Hobbes): knowing, or sharing the knowledge of anything, together with another • Not overly helpful

5. Perhaps slightly more helpful…?

7. Kinds of Consciousness • Chalmers: • “Psychological” consciousness • “Phenomenological” consciousness • Better: • Psychological problems of consciousness • Phenomenological problems of consciousness

8. “Psychological” Consciousness • Chalmers: • “awakeness, introspection, reportability, self-consciousness, attention, voluntary control, knowledge, awareness” • The “easy” problems • I.e., those explainable in principle infunctional / computational or neural terms, viz. …

9. “Psychological” Consciousness “# the ability to discriminate, categorize, and react to environmental stimuli; # the integration of information by a cognitive system; # the reportability of mental states; # the ability of a system to access its own internal states; # the focus of attention; # the deliberate control of behavior; # the difference between wakefulness and sleep.” [etc.](Chalmers 1995, “Facing Up to the Problem of Consciousness”) • I.e., “awareness” = Block’s “access” consciousness

10. “Psychological” Consciousness • Models: • “Cartesian theater” • a big “no-no” for humans • “global workspace” • Baars, Franklin, Dehaene, et al. • Anderson’s ACT-R buffers • “multiple drafts”, “fame in the brain” • Dennett

11. On “Multiple Drafts” • “On the critical question of which version of the novel [Frankenstein] is truest or best, however, [Charles E.] Robinson [editor of a scholarly edition of the Frankenstein Notebooks] demurs: ‘These texts of Frankenstein are what we call fluid texts,’ he says. ‘There is no single edition we can judge to be the best.’ ” • Howard, Jennifer (2008), “The Birth of ‘Frankenstein’,” Chronicle of Higher Education 55(11)(7 November): B12-B15; quote on p. B15. • For “fluid texts”, read “multiple drafts”.

12. “Psychological” Consciousness 1.5. “Reflexive” consciousness (Block) • special case of access consciousness • HOT (Rosenthal) • self-representational experiences (Kriegel) • Any of these models: • global workspace • HOT • multiple drafts, … could be implemented… • neurally • computationally

13. “Phenomenological” Consciousness • “experience”,“what it’s like”,“qualia” • ? • yes (Searle, Chalmers, Nagel, McGinn, Block, G.Strawson) • no (Dennett)…

14. “Phenomenological” Consciousness • “ ‘I can explain to you what love is until I turn blue in the face. I can take two weeks to explain everything to you…. ‘But there is no way I can make you feel it until you feel it.’ ” (p. 40) • Schmidle, Nicholas (2008), “Faith & Ecstasy”, Smithsonian 39(9) (December): 36-47. • Cf. Jackson’s “Mary” the color-blind color scientist • Dennett: • Qualia can’t be described (in language) •  Don’t have to/can’t explain them

15. “Phenomenological” Consciousness • Dennett (cont’d): •  qualia •  only reports of them • Don’t have to explain why you experience green or pain • Because you don’t! • Only have to explain why you say that you do! • cf.: How would your experience be different if Earth revolved around Sun? (Wittgenstein) • What we think are qualia are really just states of psychological consciousness

16. “Phenomenological” Consciousness • Could “phenomenological” consciousness (qualia) be nothing but neuron firings? • yes: • Searle: It’s just biology (like digestion) • WJR • It’s biology for humans… • but it could be implemented otherwise for computers • (more later) • no: • Chalmers:  non-physical, phenomenological properties • McGinn: It’s an unsolvable mystery (for us) • Nagel: It can only be experienced… • yes?: • G.Strawson: • Because everything is “experiential”, including neuron firings.

17. Nagel:What Is It Like to Be a Bat?

18. What Is It Like to Be a Bat? • Cf. “The Boy Who Sees through Sound” • Discovery Health documentary • People (14 July 2006) • http://www.people.com/people/article/0,26334,1212568,00.html

19. Is “Consciousness” Univocal? • Maybe there are lots of different kinds of,or aspects to, consciousness • Maybe more than one theory is correct • Block, in Cognition 79 (2001): 217

20. The Hard Problem (Chalmers) • Recall the distinction between: • Psychological concept of mind/consciousness: • as causal/explanatory basis of behavior • functional characterization • what mind does • Phenomenal concept of mind/consciousness: • experience, qualia, what it’s like • how mind feels

21. The Hard Problem • The “hard” problem: • “the problem of experience” • How are organisms subjects of experience? • Why do we experience sensations as we do? • Why & how does physical processing give rise to our rich inner life?(all quotes/paraphrases from Chalmers 1995)

22. A Brief Look Ahead • Suggestion: • Easy problem… • i.e., the functional characterization of psychological consciousness • … is like a recurrence relation or recursive clause of a recursive definition or mathematical structuralism • Hard problem… • i.e., qualia, or phenomenal consciousness • … is like the initial conditions or base case or objects that “play roles” in mathematical theories

23. Chalmers’s Zombie Argument(simplified version) • A “zombie” is_def a creature that isphysically & behaviorally indistinguishable from us,but that has no conscious experiences. • http://consc.net/zombies.html • http://plato.stanford.edu/entries/zombies/ • Physicalism is_def the theory that mental states & processes (logically) supervene on physical S&P • I.e., any physical duplicate of me would also be a psychological duplicate • Physicalism  zombies are not conceivable • But zombies are “conceivable” •  Physicalism is false •  Psychological phenomena (e.g., qualia) are something over and above physical phenomena

24. Ways to React to the Zombie Argument • That’s right! (Chalmers) • So we’d better devise a separate theory of psychological consciousness • take mental terms as primitive, not characterizable in physical terms • cf. Newton & gravity • + some psychophysical laws to tie them in with the physical world • mostly 1-1 correspondences

25. Ways to React to the Zombie Argument • There can’t be any zombies • Any sufficiently complex cognitive system (including any duplicates of me) will have just as much subjective mentality as I do • Dennett: I.e., none • Or: Commander Data will really be just as phenomenally conscious as I am (and I really am so!) (*)

26. Ways to React to the Zombie Argument • (*) How to give a zombie consciousness? • A calculator has the ability to add • but it does so unconsciously, zombie-like • Give Cassie a theory of math cognition • then she’d be aware of adding • she’d be conscious of it in both the psychological sense and in the phenomenal sense • she’d have the experience of adding • but what gives her that experience? • perhaps Rosenthal-like HOT?

27. Ways to React to the Zombie Argument • There can be zombies: • There are plenty of unconscious cognitive processes: • “People who solved puzzles with insight activated a specific subset of cortical areas. Although the answer seemed to appear out of nowhere, the mind was carefully preparing itself for the breakthrough. …The scientists refer to this as the "preparatory phrase," since the brain is devoting its considerable computational power to the problem. The various sensory areas, like the visual cortex, go silent as the brain suppresses possible distractions. "The cortex does this for the same reason we close our eyes when we're trying to think," Jung-Beeman said. "Focus is all about blocking stuff out " ” (New Yorker, 28 July 2008, p. 43) • All of this is unconscious; so, zombies are possible • but they could become conscious if another part of the brain were aware of it, or watching it, HOT-like • I.e., “absent” qualia • So why couldn’t all of them be unconscious?

28. There Can Be Zombies • This is the Really Hard Problem: • But then why do we experience some of them? • Other really hard problems in the vicinity: • Why do we experience things as we do and not another way? • cf. inverted qualia • Why do we experience red as we do (however we do) and not as the sound of a bell? • cf. synaesthesia

30. Qualia • A “quale” (plural: “qualia”) is: • a “raw feel”, • a “phenomenal experience”, • “what it’s like” • It’s what you experience when you… • sense a color, • or hear a sound, • or taste, or smell, or touch. • It’s what Chalmers says needs to be explained

31. Qualia: The Classic Problem • Psychological consciousness can be characterized functionally (i.e., computationally) • I.e., in terms of causal and logical relations… • between inputs and internal concepts, • among internal concepts, • & between internal concepts and outputs • Qualia cannot be characterized functionally • Because of the possibilities of: • absent qualia • inverted qualia •  Qualia are not psychological • or else: Psychological consciousness can’t be characterized functionally

32. Do Qualia Exist?—Wittgenstein’s Beetle in the Box • "Suppose everyone had a box with something in it: we call it a ‘beetle’. No one can look into anyone else's box, and everyone says he knows what a beetle is only by looking at his beetle. — Here it would be quite possible for everyone to have something different in his box. One might even imagine such a thing constantly changing. — But suppose the word ‘beetle’ had a use in these people's language? — If so it would not be used as the name of a thing. The thing in the box has no place in the language game at all; not even as a something: for the box might even be empty. No, one can ‘divide through’ by the thing in the box; it cancels out, whatever it is." • (Ludwig Wittgenstein, Philosophical Investigations I, §293)

33. Qualia • Are qualia beetles in boxes? • Dennett: yes! • Chalmers: • maybe (?) • but I do have a beetle in my box • even if zombies don’t have beetles in theirs!

34. Are Qualia Beetles in Boxes? • WJR: • we do have qualia • even if we may be misled by them or misremember them • we are phenomenally conscious • even if sometimes we may not remember it • e.g., “blanking out” when driving or daydreaming

35. The Hard Problem…for me! • No matter how detailed our theories of psychological consciousness are,I do experience qualia • Castañeda: • Philosophy must be done in the first person, for the first person • What is that which I experience?What is experience itself? • If I try to characterize it in terms of other aspects of my “mental economy”,it loses its “raw feel” nature • But if it is “primitive”, how can I understand it? • Want a theory of qualia that is consistent with computational theory of consciousness

36. 2 Main Questions about Qualia • Why (& how) do we experience anything rather than nothing? • the zombie question • the really hard problem • Why are our qualia as they are& not like something else? • answer may depend on answer to #1

37. Why Do We Experience Anything Rather than Nothing? • Some plants are sensitive to light,some to what we would call odors • I.e., airborne chemicals • Can they “see” or “smell”? • Do we see or smell? • Or are we, too, merely light- & chemical-sensitive? • Does anything further happen in the brain? • I.e., qualia? • Or are qualia just our sensitivity to the light & chemicals? • Or is there any sensitivity (or sensation) at all?

38. Why Do We Experience Anything Rather than Nothing? • Cf. visual quale of seeing a red (traffic) light with olfactory quale of an odor • Cf. these with the lack of an olfactory quale: • We are qualitativelyinsensitive to many odors • We are certainly less sensitive than a dog • Yet ly these odors do influence our behavior • “blind smell”; cf. blindsight • If so, then we are at least partial zombies • How could that be? • Why is there such a difference? • Does the (visual or olfactory) quale do anything?

39. Why Do We Experience Anything Rather than Nothing? • Cf. my visual quale of a red light with my absence of a visual quale for infrared light • Suppose infrared light influenced my behavior but I was not subjectively aware of the IR light • I could be objectively aware of it: • via an objective sensing device • via monitoring my brain • Would that feel like anything? • Maybe like an intuition • That’s a quale, but not necessarily a quale of the IR light • 2nd-order quale? HOT? • But probably not like a visual experience of red light • It wouldn’t be a “deeper” red

40. Why Do We Experience Anything Rather than Nothing? • What’s the difference in my behavior between: • my reaction to the quale of red light • & my reaction to IR light w/o quale? • Case 1: • I can voluntarily react (or not react) to the quale of red light • doesn’t run afoul of problem of free will: • whatever free will turns out to be will work here • Case 2: • I have no choice • especially if there is not even an intuition

41. Why Do We Experience Anything Rather than Nothing? • So we can be partial zombies • but not complete zombies • because: • a complete zombie would have no free will • but we do • If the complete zombie had free will,it would then also have to have some HOT/access/awareness of the impingement of the external object(s)… • chemicals for odor, photons for vision, etc. …on its sensory apparatus

42. Why Do We Experience Anything Rather than Nothing? • Knowing that the external object has so impinged… • being aware of its impingement …from the 1st-person POV… • i.e., subjective awareness • not objective awareness …is the experience of a quale • but ly  “inverted” qualia • i.e., what the quale feels like may  physical implementation

43. Why Are Some Stimuli Experienced as Colors & Others as Sounds? • ◊ly because of different sources? • photons • sound waves • chemicals in air • But could be all felt on a common spectrumrather than by orthogonal experiences • ◊ly they are: synaesthesia? • Why are some things experienced at all,& some things differently, but others not at all? • ◊ly because of evolutionary usefulness • voluntary ability to perform the “4 Fs” • odors are not useful to us, but are to dogs

44. Qualia • Chalmers: • A mental state or process (MSP)can be characterized functionally • “external” to the mental state or process • “behavioral” • in terms of the MSP’s I/O relations to other MSPs • its “role in the cognitive economy” • A conscious MSP can also be characterized by “what it’s like”—its quale • “internal” • “phenomenal” • by definition: without functional role • like Wittgenstein’s beetle in the box

45. Qualia • Cf. the monetary economy: • A dollar has the value it has because of the role it plays in the world monetary economy • Does it have an intrinsic value? (a quale?) • Dennett: • Does a dollar have “something logically independent of its functionalistic exchange powers”? • no: there is no economic theory of such intrinsic value • WJR: • at best, $’s intrinsic value is…its role in the world economy. • might play several roles at once • cf. Hofstadter on value of Polish zloty • Maybe: the value of the paper it’s printed on? • But that value is a function of the world monetary economy!

46. Qualia • Cf. axiom systems & intended interpretations: • Can characterize the natural numbers only as: • any sequence that satisfies Peano’s axioms • But an  of sequences do that • There’s no way to pick out “the” natural numbers • trying to do that is like trying to characterize qualia • “Arithmetic is, in this sense, all there is to number: there is no saying absolutely what the numbers are; there is only arithmetic” • Quine 1969: 45 • I.e., numbers : qualia = arithmetic : cog. economy • Maybe: a cog. agent’s internal mental representation of numbers corresponds to the qualia?

47. Qualia • Benacerraf 1965: “What Numbers Could Not Be” • 3 is neither { Ø, {Ø}, {Ø,{Ø}} } nor {{{Ø}}} (& it can’t be both); • each has properties & relations that the other lacksand that are irrelevant to numbers, e.g.: • on both theories, numbers have set-theoretic cardinality • on one theory, |3| = 3; on the other, |3| = 1; • on one theory, 1  3; on the other, 1  3 • none of these are true of the natural number 3 • “Any object can play the role of 3” • “Arithmetic is…the science that elaborates the abstract structure that all progressions have in common….It is not…concerned with particular objects—the numbers. The search for which independently identifiable particular objects the numbers really are…is…misguided….”

48. Qualia • What is a graph? • =def a structure consisting of: • a set V of vertices • & a set E of edges, • with certain relationships among the members of V & E • But what is a vertex? what is an edge? • anything that satisfies the relationships among the members of V & E • So, a telephone network really is a graph,because we can take phones to be vertices& phone connections to be edges • It’s not merely that a phone network can be modeledas (or “by”) a graph • It really is one!

49. Qualia • Logically speaking, vertices & edges are (types of) variables that can take as values certain phones & connections • such talk of variables is just talk of roles that can be played by certain (usually physical) objects • the objects implement those roles (i.e., those abstractions)

50. Qualia • Veblen (on his axiomatization of geometry): • “The terms ‘point’ and ‘order’…differ from the other terms of geometry in that they are undefined.” (p. 344) • Because they are undefined, we are not told what they are • Therefore, they can be (implemented by) anything that can play their roles • Cf. Hilbert on geometry: • "One must be able to say at all times—instead of points, lines, and planes—tables, chairs, and beer mugs.”