Rod Hay wrote: > With consciousness, it is true that many higher functions can be explained > by chemical changes in the brain, but it has also been shown that ideas, > behaviour, attitudes, etc., can affect the underlying chemistry. "Explain" and "affect" are misleading here. Chemical changes in the brain don't exactly "explain" anything. If they did we could read someone's mind with an EEG. In fact it is difficult to know what the correct verb would be to connect "chemical change" and "thought." And "affect"is much too weak to describe the relation of an attitude to chemical change. "Is" would probably be better in both cases -- but would still be misleading. An explanation of how the firing of neurons "is" a thought is precisely what we don't have. That is, we know that to think or feel or perceive takes the physical form of chemical action in the brain, but that merely names what needs to be explained. The link, identity, whatever is most dramatic of course in cases of malfunction. When I had to shift anti-depressants about 14 years ago, there came a Tuesday afternoon when I had to dismiss a class because my voice ran down like a primitive windup record player -- the words spacing out and stopping. The next morning (I had upped the dosage of the new anti-depressant 5 days earlier) I was sitting in my office at 8:55 wondering how I could teach my 9:00 class when with an almost audible click my "mind" came back. I could think.You just can't separate chemistry and thought in terms of one "explains" or "affects" the other. Carrol Re emergent properties. If you take (say) 20 dynamos and attach each to an electric clock, every clock will run at a slightly different speed, some slower, some faster, than they should. If you connect all 20 together, so one can draw power from another, they will all run at the same speed. It's called a "virtual governor." There is no "thing" there but the system works as though there were a governor regulating speed. That's an emergent property, but it isn't all that clear that thought can be so described. In fact "emergent property" might just be another case of substituting the name of a problem for a solution to the problem.
