CSE 719: Computational Theories of Consciousness, Fall 2009 ======================================================================== Crick & Koch quotes (for bib info, see online bibliography) ======================================================================== 1. C&K 1990: ------------------------------------------------------------------------ a) "Attempting to infer the internal structure of a very complex system using a 'black-box' approach (i.e., manipulating the input variable swhile observing the output of the system) will never lead to unique answers. In short, such methods are not by themselves powerful enough ever to solve a problem, though they are good enough to suggest tentative solutions." (page 263, column 2, paragraph 0 [i.e., 263c2p0]) Note added 12/15: In this paper, C&K observe that perceptual systems translate world events into neurochemical events. This seems to be the converse of the Hard Problem. 2. C&K 1998: ------------------------------------------------------------------------ a) "Why does not our brain consist simply of a series of...specialized zombie mechanisms? We suggest that such an arrangement is inefficient when very many such systems are required. Better to produce a single but complex representation and *make it available* for a sufficient time to the parts of the brain that make a choice among many different but possible plans for action. This, in our view, is what seeing is about." (98c1p4) b) "the biological usefulness of visual consciousness in humans is to produce the best current interpretation of the visual scene in the light of past experience...and to make this interpretation directly available, for a sufficient time, to the parts of the brain that contemplate and plan voluntary motor output..." (98c1p2) 3. K&C 2001: ------------------------------------------------------------------------ "Why aren't we just big bundles of unconscious zombie agents? Why bother with consciousness, which takes hundreds of milliseconds to set in? It may be because consciousness allows the system to plan future actions, opening up a potentially infinite behavioral repertoire and making explicit memory possible." (c3p1) 2.1. C&K 1998: ------------------------------------------------------------------------ c) "How can you possibly explain the vivid visual scene you see before you in terms of the firing of neurons? The argument that you cannot explain consciousness by the action of the parts of the brain goes back at least as far as Leibniz. But compare an analogous assertion: that you cannot explain the 'livingness' of living things (such as bacteria, for example) by the action of 'dead' [better: non-living] molecules. This assertion sounds extremely hollow now....It is entirely possible that the very elaborate nature of neurons and their interactions, far more elaborate than most people imagine, is misleading us, in a similar way, about consciousness." (103c2p3-104c1p0) 3. C&K 2003: ------------------------------------------------------------------------ a) "The most difficult aspect of consciousness is the so-called 'hard problem' of qualia...." (119c1p1) 4. Searle on Crick (Mystery of Csness 1997:28) ------------------------------------------------------------------------ "the problem of qualia is serious. It is this: How is it possible for physical, objective, quantitatively describable neuron firings to cause qualitative, private, subjective experiences? How, to put it naively, does the brain get us over the hump from electrochemistry to feeling?" 2.2. C&K 1998: ------------------------------------------------------------------------ d) "Psychophysical evidence for short-term memory (Biederman et al. [!]) suggests that if we do not pay attention to some part or aspect of the visual scene, our memory of it is very transient can can be overwritten (masked) by the following visual stimulus. This probably explains many of our fleeting memories when we drive a car over a familiar route." (99c1p4) 1.1. C&K 1990: ------------------------------------------------------------------------ b) "So far no single area has been found whose neurons correspond to everything we see. How is it, then, that we seem to have a single coherent visual picture of the scene before us?" (267c2p0) c) "We suggest that one of the functions of consciousness is to present the result of various underlying computations and that this involves an attentional mechanism that temporarily binds the relevant neurons together by synchronizing their spikes in 40Hz oscillations" (272c1p4) 2.3. C&K 1998: ------------------------------------------------------------------------ e) "Much has been made of the presence of oscillations in the [40Hz] range....The existence of such oscillations remains in doubt in higher visual cortical areas....We remain agnostic with respect to the relevance of these oscillations to conscious perception." (103c1p4-103c2p0) 3.1. C&K 2003: ------------------------------------------------------------------------ b) "the classical binding problem...was mainly concerned with how two different objects/events could be 'bound' simultaneously. On [our] view, the 'binding' of the features of a single object/event is simplyu the membership in a particular coalition. There is no single cortical area where it all comes together. [Cf. Dennett's Cartesian theater?] ...[Coalitions] bind by ineracting in a diffuse manner." (123c2p1) c) "We no longer think that synchronized firing, such as the so-called 40Hz oscillations, is a sufficient condition for the NCC." (123c3p2) 2.4. C&K 1998: ------------------------------------------------------------------------ f) "the major problem [of meaning]...is: How do other parts of the brain know [sic!] that the firing of a...set of similar neurons produces the conscious percept of, say, a face? How does the brain know what the firing of those neurons represents? Put in other words, how is meaning generated by the brain? This problem has two aspects. How is meaning expressed in neural terms? [cf. Fodor's LOT?] And how does this expression of meaning arise? We suspect that meaning derives both from the correlated firing...and from the linkages to related representations. [Cf. holism] For example, neurons related to a certain face might be connected to ones expressing the name of the person whose face it is, and to others for her voice, memories involving her and so on, in a vast associational network, similar to a dictionary or a relational database. Exactly how this works in detail is unclear." [Cf. SNePS] (104c2p3-4) g) "In the long run, finding the NCC will not be enough. A complete theory of consciousness is required, including its fnl role. With luck this might illuminate the hard problem of qualia. **It is likely that scientists will then stop using the term consciousness except in a very loose way.** [Cf. Eliminativism?] After all, biologists no longer worry whether a seed or a virus is 'alive'; they just want to know how it evolved, how it develops, and what it can do." (105c2p2) 5. Searle on Koch (Searle 2005) ------------------------------------------------------------------------ "according to [Koch], we never perceive objects in the real world, not even our own bodies. For example, you never see the chair in front of you, but only a mental representation of the chair in your brain. ...The theory that we can never perceive the real world but only our inner pictures of it is the single most disastrous view in the past four centuries of epistemology. The arguments for it (Koch gives none, by the way) are invariably bad and the consequences are worse. This theory makes it impossible to have a public language or publicly verifiable knowledge. All we can ever talk about is our own solipsistic mental pictures. Historically this view leads from Descartes to Berkeley and then to Kant and eventually to Hegel. It is a road down which no sane person should wish to go. (sect. 4) * Arg. from Illusion * Arg. from perceptual time lag * Need a public language? -- cf. Russell 1918, Russell: "When one person uses a word, he [sic] does not mean by it the same thing as another person means by it. I have often heard it said that that is a misfortune. That is a mistake. It would be absolutely fatal if people meant the same things by their words. It would make all intercourse impossible, and language the most hopeless and useless thing imaginable, because the meaning you attach to your words must depend on the nature of the objects you are acquainted with, and because different people are acquainted with different objects, they would not be able to talk to each other unless they attached quite different meanings to their words. . . . Take, for example, the word Piccadilly. We, who are acquainted with Piccadilly, attach quite a different meaning to that word from any which could be attached to it by a person who had never been in London: and, supposing that you travel in foreign parts and expatiate on Piccadilly, you will convey to your hearers entirely different propositions from those in your mind. They will know Piccadilly as an important street in London; they may know a lot about it, but they will not know just the things one knows when one is walking along it. If you were to insist on language which was unambiguous, you would be unable to tell people at home what you had seen in foreign parts. It would be altogether incredibly inconvenient to have an unambiguous language, and therefore mercifully we have not got one. (Russell 1918: 195-196.) cf. Rapaport 2003 on negotiation. But see "worst argument"