From: THEORM::STAPP 21-OCT-1996 20:07:29.38 To: SMTP%"phayes@picayune.coginst.uwf.edu" CC: STAPP Subj: reply to yours of oct15 Dear Pat, Oct 21, 1996 Your letter of Oct 15 began with a quote from my previous note: >I have answered this argument by pointing out the principled difference in >kind between, on the one hand, the abstractions from our experiences of >the world about us that comes chiefly through our visual sense, and that >are therefore readily compared by us to experiences of the kind from which >they were abstracted, and, on the other hand, the brain activity that *is* >our conscious experience, but that is represented within CM >as something altogether different from the experience that it actually >is: this brain activity is represented within CM by neuron pulses >etc, that are not abstractions from "the patch of blue" that the experience >actually is. You replied: "Ah, I see the problem that is bothering you. It is nothing whatever to do with CM or QM. It is the difference between the neural event, as seen from outside, and the quality of the experience. This is an old philosophical straw. The computational perspective gives an immediate reply to this old puzzle: the subjective experience is the *meaning* of the representation encoded by the neural event. My experience of blue isnt blue for much the same reason that the word "blue" isnt blue: the map is not the territory. If you want to respond that the notion of "meaning" isnt in CM, there are two replies. It isnt in QM either; but, more to the point, we can make machines which can be understood within CM but for which an adequate account requires talk of the meanings of the symbols encoded within them, ie computers." (End of quote from PH) You appear to recognize and reaffirm, here, a difference in kind between the neural event as seen from the outside (the objective event) and the quality of the experience (the subjective event associated with it). You say that: "the subjective experience is the *meaning* of the representation encoded in the neural event." Later on you say: "... we can make machines which can be understood within CM but for which an adequate account requires talk of the meanings of the symbols encoded within them." Thus you are in effect trying to substitute "meaning" for "experience". The "meanings" of these symbols derives from the fact that they are imbedded in, or can be imagined to be imbedded in, a decoding machine, i.e., in an environment that transforms the symbols, singly or collectively, into corresponding activities of the decoding or environmental system. This objective "source of the meaning" resides in the system that we computer/physical scientists and philosophers observe. *We* see meaning. This meaning is something that *we* experience. *We* are the human observers who are looking at the computer from the outside. What we are observing is the "behaviour" of some physical system describable in terms of the concepts of CM. Alternatively, we may be not observing any actual physical system that lies outside our bodies, but rather contemplating an abstraction from experiences of this sort: we may be contemplating a certain "model" based on abstractions from our experiences of the world about us, including relationships such as inclusion, disjunction, conjunction, etc. We can distinguish "objective meanings" that we can ascribe to the observed or contemplated system based purely upon its internal properties, from "subjective meanings" related to one's own personal interests in the system. The interesting question arises when we try to include a human observer, or contemplator, Sam Smith, in the system that is being observed by the rest of us. If we treat Sam just as we treated the computer, then we shall be able to identify certain behavioural features and ascribe "objective meaning" to these features purely on the basis of behavioural connections: we shall be able to ascribe meaning to neural events in terms of their behavioural consequences in the neural dynamics. Thus suppose Sam is contemplating Pythagoras's Theorem, and is visualizing a right triangle. We who are observing Sam's brain (say, with very sensitive but non disturbing probes) can "see" the neural event but not the triangle that he experiences. Yet it may be eventually true that someone's comprehension of brain dynamics will great enough so that that he can "see" the following "objective meaning" of the neural event: Sam will presently utter the words "I am visualizing a right triangle". This fact may also have some "subjective meaning" to some outside, viewer in terms of his own situation or interest. Your suggestion is evidently to identify Sam's "subjective experience" with "Sam's meaning" of the objectively described neural event. This would, of course, make Sam's sort of "subjective" meaning very different from the "subjective meanings" spoken of before. For there the meaning to some person was the meaning of something that he either observed through his senses, or contemplated in the form of abstractions from such observations. They were meanings of thoughts about things viewed, perhaps in imagination, from afar; not the meanings of the activities of his own brain as felt from within. It would seem more straightforward to call this new kind of "subjective meaning from within" by its usual name, "experience". One problem with the new language is that each event in a human brain has many consequences, not all of which are experienced. Thus "meaning"is too broad a category: what is "experienced" does not include everything that has some significance for the dynamical development of the system. Also, significance or meaning is often in terms of what is "initiated", but lies still in the future: I seem to experience the triangle *before* I utter the words "I am experiencing a triangle". And many consequences lying still further in future are not experienced "now". Experiences seem to be connected to some finite-duration process of laying down certain special types of "memory structures" that normally can be re-accessed at a later time. So, again, "meaning" is too broad a category to be equated to what we mean by the word "experience". The latter is something that has certain properties independently of some definition that can be arbitrarily set down: it is not a free category that can simply be defined so as to create a convenient logical framework. You say that the issue here has nothing whatever to do with CM and QM. But CM is a theoretical framework based on objective concepts abstracted, basically, from our visual experiences of the world outside of us, and it is unitary in this sense. But QM naturally has two (inimately entangled) kinds of things: 1) the local operators, which are like the material things of CM in that their evolution throughout all of spacetime is fixed by deterministic equations of motion; and 2) the chnges in the state vector, which are like the experiential things of CM in that they pick the single *real situation* out from among the many merely possible ones. So how is this all tied to the issue, which is my claim that: "The same orthodox principles of CM that *do* entail the motion of Foucault's Pendulum *do not* entail the existence of consciousness". Our previous discussions have brought us to the point where I identified the principles of CM as including the identification of features of a CM theoretical model such as `the location of the center of mass of something such as the pointer of some measuring device as positioned on a backdrop of numbers enscribed on some dial' with `an observation of such a coincidence of pointer and location a dial': the correspondence between CM theory and experience is in terms pointer readings, which can be interpreted either as properties of a theoretical model of the objective physical system, or as subjective experiences. It is this principle of psycho-physical parallelism of `readings on devices' that allows CM to be relevant to our experiences. The motion of the pendulum can be described in terms of readings on devices, namely the readings on clocks and sightings of the pendulum passing over certain marks on the floor. These ideas are the basis of Einstein's analysis leading to the special theory of relativity. They are also the basis of Bohr's theory of QM, through its crucial dependence on "classical description". So this *is* orthodox CM: it is the psycho-physical principle that both Einstein and Bohr took as basic. You said: " If you allow CM to include such descriptions [which link the vocabulary of springs, gases, etc., to that of classical mechanics] then I still fail to see why there might not be similar descriptions of subjective things like thoughts and experiences." But CM already has its principle of psycho-physical correspondence, and this principle keeps the concepts in the domain of `abstractions from visual experiences of things viewed from afar'. Of course, this does not mean that one could not *add* something else onto orthodox present-day classical mechanics. But I stressed from the beginning of this series of exchanges that I was not denying, in this discussion, the possibility that some new principle could be added onto the present CM, in order to bring in consciousness; my arguments for this stronger conclusion are of a very different kind. Here I was only defending the much more conservative claim that the (orthodox) principles of CM do not entail consciousness. But this weaker claim is important in its own right, as I have stressed and explained in earlier letters. Best regards, Henry