Unreal Nature

February 17, 2009

The Mereological Fallacy

Filed under: Uncategorized — unrealnature @ 7:31 am

Brains are no more conscious than they are capable of taking a walk or holding a conversation. True, no animal could do either of these things without a properly functioning brain. But it is the person, not the brain, that engages in these activities.

At risk of seeming to want to have the last word on a topic, ‘free will’, that Dr. C introduced, and has now concluded, I want to get this last bit into the record because I think it goes to the crux of why we can’t even get to what it is that we’re trying to get to. All of this is from (yet another) review of a book, Philosophical Foundations of Neuroscience, 2003, by Bennett, M.R. and Hacker, P.M.S; reviewed by Dennis Patterson in Notre Dame Philosophical Reviews.

Bennett — a distinguished neuroscientist — and Hacker — the preeminent scholar of Wittgenstein’s thought — have teamed up to produce a withering attack on the conception of the mental that lies at the heart of contemporary neuroscience. Although neuroscientists are committed materialists, and adamantly insist on this aspect of their anti-Cartesianism, they have, Bennett and Hacker argue, merely jettisoned the dual substance doctrine of Cartesianism, but retained its faulty structure with respect to the relation of mind and behavior.

… What interests Bennett and Hacker about the Cartesian replacement of Aristotelian thought is the extent to which contemporary neuroscientists have failed to go far enough in their rejection of Cartesianism, thereby threatening the integrity of their scientific endeavors. In brief, these are the key elements of Descartes’s legacy:

(1) Descartes reconceived the soul “not as the principle of life, but as the principle of thought or consciousness” (p. 26), a thesis which led to the idea that the mind was separate from the body in all respects. This formulation inevitably “casts a long shadow over neuroscientific reflection . . . .(p. 26);

(2) Descartes further complicated his position by insisting that while distinct, mind and body are united. The central problematic to emerge for both Cartesianism and its inheritors is how to explain the connection between mind and body;

(3) The only thesis of Descartes that withstood critical objection was his claim that “explanation at the neurophysiological level will be in terms of efficient causation” (p.27). In this respect, Bennett and Hacker remind us that “Descartes contributed substantially to advances in neurophysiology and visual theory” (p.27).

Once the Cartesian paradigm took hold, it fell to neuroscientists to work out its implications at the experimental level. For two generations (from Sherrington to his protégés) modern brain scientists remained fundamentally Cartesian (i.e. they adhered to the Cartesian explanatory framework of the relation of mind to body). The third and current generation of neuroscientists repudiated Cartesian dualism, replacing the mind with the brain as the explanatory locus of human psychological and emotional capacities. But, Bennett and Hacker argue, merely replacing the mind with the brain falls short of a repudiation of the structure of the Cartesian explanatory system.

In Chapter 3 of Part I – “The Mereological Fallacy in Neuroscience” – Bennett and Hacker set out a critical framework that is the pivot of the book. They argue that for some neuroscientists, the brain does all manner of things: it believes (Crick); interprets (Edelman); knows (Blakemore); poses questions to itself (Young); makes decisions (Damasio); contains symbols (Gregory) and represents information (Marr). Implicit in these assertions is a philosophical mistake, insofar as it unreasonably inflates the conception of the ‘brain’ by assigning to it powers and activities that are normally reserved for sentient beings. It is the degree to which these assertions depart from the norms of linguistic practice that sends up a red flag. The reason for objection is this: it is one thing to suggest on empirical grounds correlations between a subjective, complex whole (say, the activity of deciding and some particular physical part of that capacity, say, neural firings) but there is considerable objection to concluding that the part just is the whole. These claims are not false; rather, they are devoid of sense.

They also cover philosphers of mind, who “are themselves prone to similar conceptual errors”. They then return to discussion of neuroscientists:

… Some neuroscientists have themselves fallen victim to the logical fallacies of philosophers of consciousness. Damasio, for example, explains vision as the production of mental images in the brain. Bennett and Hacker object that this explanatory model makes no sense, since it raises objections of another kind; the hypothesis that mental images are real features instantiated in the brain would not seem subject to empirical verification and, even if it were, it would fail to illuminate vision as we know it. Of course, there is brain activity associated with vision. But it is unhelpful and of little value to say that “we” perceive the image of the apple produced in our brain. The question Bennett and Hacker ask, “How is it that we see it?” (p. 305) cannot receive philosophical illumination by the question “Where ‘in’ the brain is the image?” The reason is that that question ignores the all-important one: “Who, or what, is doing the seeing?” The error is in thinking that seeing an object is itself somehow reducible to a quale behind vision. But it is not. And the object of normal vision is not an image of any kind either. Neuroscientists may find inductive correlations between seeing certain items (e.g. lines, corners, curves) and brain activity. But finding such correlations is not the same as reducing one to the other. It is the reduction that leads to a muddle.

Finally, the review returns to philosophers’ treatments of the issue, ending with that of John Searle:

… In the case of Searle, Bennett and Hacker find much with which they agree. Cartesian dualism, behaviorism, identity theory, eliminative materialism and functionalism are all rejected, and rightly so. Searle advocates “biological naturalism,” the view that consciousness is a biological phenomenon, a proper subject of the biological sciences (p. 444). Bennett and Hacker serve up no objection here. It is when Searle claims that “mental phenomena are caused by neurophysiological processes in the brain and are themselves features of the brain” (Searle, Rediscovery, p. 1) that Bennett and Hacker demur. Searle’s claim commits the mereological fallacy discussed earlier. Brains are no more conscious than they are capable of taking a walk or holding a conversation. True, no animal could do either of these things without a properly functioning brain. But it is the person, not the brain, that engages in these activities.

This is a fascinating discussion of the core problem of theory of mind. Highly recommended. [ link ]

Addendum: The reviewer of the above, Dennis Patterson, sent me, via email, a link to a page from which you can get to a downloadable .pdf file that he co-authored with Michael S. Pardo, Philosophical Foundations of Law and Neuroscience (posted on February 6, 2009). I’ve only skimmed it, but it looks very interesting.



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