[This is for grad students taking the course]
The causal structure of cognition can be simulated but not implemented computationally, just as the causal structure of a furnace can be simulated but not implemented computationally. Heating is a dynamical property, not a computational one. A computational simulation of a furnace cannot heat a real house (only a simulated house). It lacks the essential causal property of a furnace. This is obvious with computational furnaces. The only thing that allows us even to imagine that it is otherwise in the case of computational cognition is the fact that cognizing, unlike heating, is invisible (to everyone except the cognizer). Chalmers’s “Dancing Qualia” Argument is hence invalid: Even if there could be a computational model of cognition that was behaviorally indistinguishable from a real, feeling cognizer, it would still be true that if, like heat, feeling is a dynamical property of the brain, a flip-flop from the presence to the absence of feeling would be undetectable anywhere along Chalmers’s hypothetical component-swapping continuum from a human cognizer to a computational cognizer -- undetectable to everyone except the cognizer. But that would only be because the cognizer was locked into being incapable of doing anything to settle the matter simply because of Chalmers’s premise of input/output indistinguishability. That is not a demonstration that cognition is computation; it is just the demonstation that you get out of a premise what you put into it. But even if the causal topography of feeling, hence of cognizing, is dynamic rather than just computational, the problem of explaining the causal role played by feeling itself – how and why we feel – in the generation of our behavioral capacity – how and why we can do what we can do – will remain a “hard” (and perhaps insoluble) problem.
ReplyDelete" It would not be the causal structure of planets, moving, nor gravity, attracting: it would be the causal structure of computer hardware, executing a certain algorithm, thereby formally “mirroring” the causal structure of planetary motion, as encoded in the algorithm. Two different dynamical systems, with different dynamical properties: those of the hardware, implementing the algorithm, and those of the planets, orbiting. (This is exactly the same as the two examples Chalmers concedes to be non-‐computational: flying and digestion.)"
it would seem to me that this depends very much on how 'computer' is defined. in so far as the symbols cannot be dynamical inputs/output, then probably i agree that the system would not be mirroring the dynamical system. but if the computer could take dynamic input and generate 3d dynamical output, then i would think it to be possibly for the system to mirror planetary motion.
what i am always unclear is how machine, computer and algorythm are define. often papers seem to imply that only the currently known input/output of computers are relevant. but i don't understand why it would theoritically be impossible for anything but the current input/output language of today's computer to be input/output of any computer.