On 29 July 2014 18:41, Bruno Marchal <marc...@ulb.ac.be> wrote: It is thought as a reductio ad absurdum. If consciousness supervenes on the > physical activity, then it supervenes on the movie, But there is no > computation in the movie, only a description of a computation, so > consciousness does not supervene on the physical activity of the brain, it > supervenes "directly" on the "abstract self-referential number relation > with themselves and with respect to their most probable universal > neighbors, from your laptop to gravitation and many others.
Yes, that is the only possible move to salvage CTM. But one isn't forced to take this second step. One could claim that, since there is no computation in the movie, CTM is thereby falsified. But, since Alice's overt behaviour and hence her relation to her environment are by assumption unchanged, it might not be unreasonable to suppose that her consciousness continued to supervene on the physical activity. Of course a claim of that sort could no longer be "qua computatio", but in some sense "qua materia". It's unclear how such a position could be distinguished from eliminativism about consciousness (at least, pace Brent, elimination of the possibility of *explanation* beyond physical parallelism), but it isn't prima facie incoherent. That apart, at this point in the argument, assuming one accepts the reversal and salvages CTM, some things are still not quite clear (at least to me). For example let's now assume that Alice remains conscious at the conclusion of the thought experiment, qua computatio. What is the nature of the relation between her observable brain processes and the computations that are supposed to be associated with her consciousness? And what is the relation between what is observable in general and any deeper level we may suppose to be reponsible for it? I tried to develop some intuition about this latter point with an analogy based on the distinction between an LCD screen and the movies that could be presented on it (though unfortunately it seems as if this may have got mixed up in your response with the movie in the MGA). In any case, in my analogy, all the characters and action at the level of the movie are of course generated at the deeper level of a rendering engine (which I rather inaccurately called the level of the screen). Now let's assume that this movie is some futuristic, fully-immersive, self-interpreting presentation. For the analogy to hold, the "physical constitution" of the embedded characters and environments must be fully consistent both with the action at the level of the movie and the self-interpretation of the characters. Nonetheless all these internal "observations" and "observables" are a consequence of a deeper level of "rendering", which itself has no necessity of isomorphism with anything at the level of observation. Does the idea of such a level (which must of course be "noumenal" or unobservable in principle with respect to the "level of internal observation") still make any sense in comp terms? David -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
