There are two main problems with Churchland’s discussion. First, his summary of the case for dualism is no good. Second, his arguments against dualism are no good either. In this post we’ll look at the first problem and in a second post I’ll address the second.
What are the main arguments for dualism? Churchland identifies four; he calls them the argument from religion, the argument from introspection, the argument from irreducibility, and the argument from parapsychology. To anyone familiar with the philosophical literature on dualism, this list cannot fail to seem very odd.
One problem with it is that it includes two arguments – the “argument from religion” and the “argument from parapsychology” – that dualist philosophers actually put little or no emphasis on. As Churchland presents the “argument from religion,” it amounts to little more than the claim that “Dualism must be true, because my religion says it is.” He cites no philosophers as actually having given this argument, no doubt because there aren’t any. (Yes, a philosopher who happens to believe on independent grounds that his religion is true and that it entails dualism might present that as an argument for dualism to someone who already agrees with its premises. But no dualist philosopher I can think of has ever pretended that such an argument would be a good stand-alone argument for convincing either an irreligious materialist or even someone whose attitude toward either religion or dualism is noncommittal.)
The “argument from parapsychology” no doubt does have some defenders; certainly there are serious philosophers who have taken the subject of alleged paranormal phenomena seriously either in a sympathetic way (e.g. C. D. Broad and, in recent years, Stephen Braude) or in a critical spirit (e.g. Antony Flew). But this subject does not in fact play much of a role in contemporary debates over dualism, and even those philosophers who believe that at least some purported paranormal phenomena cannot plausibly be explained away in terms of existing scientific theory (e.g. Braude) do not necessarily put such claims forward, primarily or at all, as grounds for accepting dualism.
It is in any event a mistake to think that dualism is intended as a kind of scientific hypothesis put forward as the “best explanation” of the empirical evidence, parapsychological or otherwise. The central arguments for dualism have always been attempts at metaphysical demonstration, intended to show conclusively that whatever the mind is, it cannot even in principle be material. And this brings us to the most glaring fault with Churchland’s list: He simply ignores these key arguments entirely. For example, though he purports to summarize Descartes’ own reasons for endorsing dualism, and rightly notes that Descartes thought that certain key mental phenomena are irreducible to material phenomena, he fails even to mention the two arguments Descartes put the most emphasis on: the clear and distinct ideas argument (these days often called the conceivability argument or the modal argument), and the indivisibility argument (which is related to what is often called the unity of consciousness argument). The first argument (which I have discussed in a previous post) holds that since – the argument claims – it is metaphysically possible for mind to exist apart from anything material, it cannot be material. The second holds that the mind has a kind of unity or indivisibility-in-principle that nothing material can have. (Variations on this basic idea were also defended by the likes of Leibniz and Kant.)
It isn’t like these arguments are not well known. Nor are they mere historical relics; they have defenders to this day. (For those who are interested, I discuss them in detail in my book Philosophy of Mind.) The modal argument in particular received renewed attention in the wake of Kripke’s Naming and Necessity, and thus in the years leading up to the publication of Churchland’s book. It was defended by Richard Swinburne in The Evolution of the Soul, which appeared in 1986 – two years before Churchland’s revised edition – and by W. D. Hart in The Engines of the Soul, which itself came out in 1988. (Charles Taliaferro is another philosopher who has defended it in the years since, in his book Consciousness and the Mind of God.)
Churchland also ignores – as, in fairness, almost all contemporary philosophers of mind do – what early modern writers like Malebranche regarded as the central proof of dualism, viz. that dualism follows from the very mechanistic conception of matter Cartesians and materialists hold in common. For if color, odor, taste, sound, etc., as common sense understands them, do not exist in matter itself but only in our perceptual experience of matter, then those experiences cannot be material. (I have discussed this argument in previous posts as well, e.g. here and here.)
What is in fact the chief argument for dualism, at least from the point of view of the classical (Platonic-Aristotelian-Thomistic-Scholastic) traditions in philosophy, concerns, not sensory qualities or “qualia,” but rather our capacity for abstract thought. For concepts, and our thoughts about them, are universal in a way nothing material can be, and (sometimes, anyway) determinate, precise, or unambiguous in a way nothing material can be. (I have discussed this sort of argument too in many earlier posts, e.g. here and here.) While this line of argument has also been largely ignored by contemporary academic philosophers of mind, it was defended by Mortimer Adler in the years leading up to the publication of Churchland’s book, and by 20th century Thomist writers generally. Needless to say, Churchland ignores it as well.
So, while Churchland pretends to be summing up “some of the main considerations” usually given in support of dualism, he completely ignores the arguments the most prominent dualist philosophers actually regarded as the most important, and includes arguments that dualists do not typically make use of – arguments that are either clearly feeble (the “argument from religion,” as Churchland presents it) or which rest on premises which are as controversial as dualism itself is (the “argument from parapsychology”). The rhetorical effect is obvious: The unwary reader, who assumes that a textbook will give him an accurate summary of what each side has to say, is bound to come away with a completely distorted conception of the case for dualism. In particular, he is bound to think it far weaker than it actually is.
I am not claiming that Churchland is knowingly perpetrating what looks like a pretty sleazy rhetorical tactic. I think he is, like most materialists, simply ignorant of what most dualists have actually said. He no doubt thinks he knows enough about what they say to be justified in concluding that their position is not worth looking into any further than he already has. He is wrong, but will never know that he is, because he has gotten himself onto the sort of merry-go-round that (as we have seen in recent posts) naturalists seem to have so much difficulty keeping off of: “I know that dualism is too silly to investigate any further because of how bad the arguments for it are; and I know that I must be understanding those arguments correctly because dualism is obviously just too silly to be worth investigating any further.”
The thing is, books like Matter and Consciousness contribute to the formation of the same mindset in others. As generation after generation of philosophy students are taught out of such books, the conclusion that dualism is intellectually disreputable comes to seem something that “everyone knows.” In fact, what “everyone knows” is nothing more than a bunch of straw men and circular arguments, bounced around the materialist echo chamber long enough that no one can hear anything else. (This is, of course, exactly parallel to what most atheist philosophers “know” about the classical arguments for God’s existence, as I have noted here, here, and here. The hegemony of atheism and materialism crucially depend on a stubborn and studied ignorance of what theists and dualists have actually said.)
Having said all that, Churchland is at least correct to say that what he calls the "argument from introspection" and the "argument from irreducibility" are prominent arguments for dualism. Unfortunately, what he says about these arguments is no good either. We’ll see why in part II.