- Reply to Review of Neither Brain nor Ghost
Professor McCarthy1 has carefully read many passages in my book Neither Brain nor Ghost (NBG), and clearly understands many of my main points. Unfortunately, there are other passages throughout the book that she seems to have missed, which contradict many of her criticisms. However, I have heard many of these criticisms before, so I probably have not been clear enough on these points. I welcome the opportunity to make further clarifications.
I could respond to her objection that no one believes that the brain possesses intrinsic causal powers by referring to the quotes from Jerry Fodor and Colin McGinn on pages 59 and 60. But my main point was that these kinds of concepts are the only way to make sense out of metaphors like Dennett's claim that "the Head is Headquarters" or Paul Churchland's description of the brain as "the seat of the soul." There are a variety of causal factors that are responsible for the experiences we have. These include brain activity, other kinds of body activity, light bouncing of objects, and the objects themselves. Why is it that we assume that the activities within the brain "embody" experience, while these other factors only "cause" the experience? Why is it that only causal activity within the skull is given this special honorific? The answer seems obvious until you ask the question. Once the question is asked, the only answers available are the sort that McCarthy says no one would accept: that the brain is autonomous, or a closed system, or has intrinsic causal powers which make it fully responsible for the production of mental states. There are quotes, in my book and elsewhere, which show that many philosophers and scientists do accept these answers. But the important point is that no other available answer will support the claim that the mind is identical to the brain, regardless of who acknowledges this fact. To some degree my book is a challenge to those who defend mind/brain identity theory. "If you don't use these criteria for determining mind/brain identity, what criteria should we use?" My claim is that these kinds of criteria, weak as they are, remain the only reasons we have for believing that the mind is identical to the brain.
McCarthy frets about my "insouciance about the intricate processes in the brain that are necessarily involved in the generation of the conscious experience of any organism." I felt no need to add my voice to the chorus of wonder about the brain's intricacies, but that was not meant to imply disagreement. I felt a greater need to deal with those marginalized biological facts about consciousness and cognition [End Page 87] which are not explainable solely by talking about the brain, because most people don't know about them, and because I believe they are philosophically important. (They appear mostly in chapters 2, 3 and 10.) More importantly, as I explain on page 30, the fact that these brain processes are necessary for conscious experience does not mean that they are identical to conscious experience. Mind-Brain Identity requires that those brain processes be both necessary and sufficient. It is necessary for your car to have spark plugs in order for you to drive it. But that doesn't mean the spark plugs are identical to the car, because owning a set of spark plugs is not sufficient to enable you to drive to work. So the question remains: Why is brain activity identical to consciousness, and not just necessary for it? At what point does the intricacy become both necessary and sufficient, and why should we automatically assume that all of this intricacy will take place in the skull?
When most people get to this stage in the argument, they usually reply, as McCarthy did, that, even if we can't answer that question, we still need to make a distinction between Mind and World for pragmatic reasons. She, Dewey and I all agree that there is value in what McCarthy calls the "analytic distinctions of self and world." That is why I say this on page 104 of NBG: "To...