[deleted]
Hi nmann,
Certainly, computers operate on as many varieties of energy as are available -- a computer as simple as an abacus uses mechanical energy, and one can conceive of constructing a more complex computer with, e.g., water or another fluid substituting for electricity flowing through logic gates.
" ... how does the electrochemical information coursing around in your brain relate to the symbolic information your brain outputs, as represented for instance by your post?"
George answered that in a reply to Georgina: "The placebo effect is fascinating; of course from my viewpoint it's a case of top-down action from beliefs (abstract entities) to physical systems (human bodies)." This can be generalized; the relation between thought and action is mediated by cognitive differentiation, between states of being, which is how a computer -- though by programming rather than cognition -- converts differential equations (difference equations, actually, because the computer is a finite state machine) to discrete output (information). The information can then be used as new input.
"How many transduction processes are involved, and what the heck are they?"
I don't think we need transduction to explain information processes. Though some favor the view that humans are only computers made of meat, I think that nature is more subtle, incorporating a structure by which information is continuous and infinite, which makes the meat computer -- the finite state -- view untenable. My essay in this contest explains why.
Tom