How do you get blood from a stone? Easy. Start by redefining “blood” to mean “a variety of stone.” Next, maintaining as straight a face as possible, dramatically expound upon some trivial respect in which stone is similar to blood. For example, describe how, when a red stone is pulverized and stirred into water, the resulting mixture looks sort of like blood. Condescendingly roll your eyes at your incredulous listener’s insistence that there are other and more important respects in which stone and blood are dissimilar. Accuse him of obscurantism and bad faith. Finally, wax erudite about the latest research in mineralogy, insinuating that it somehow shows that to reject your thesis is to reject Science Itself.

Of course, no one would be fooled by so farcical a procedure. But substitute “mind” for “blood” and “matter” for “stone,” and you have the recipe for Daniel Dennett’s From Bacteria to Bach and Back. The philosopher Peter Geach once wrote that we should treat materialist claims to have explained the mind the way we would treat a claim to have squared the circle: the only question worth asking is “How well has the fallacy been concealed?” In Dennett’s case, not well.

* * *

Indeed, what the Tufts University philosopher and cognitive scientist gives us is a whole battery of blatant fallacies. For example, throughout the book, Dennett makes assertions to the effect that evolution “designed” this or that. Of course, evolution, which is an entirely impersonal natural process, doesn’t really design anything. The whole point of Darwinism, as Dennett well knows, is to get rid of notions like “design,” “purpose,” and the like. Rather, evolution merely simulates design. It is as if the products of natural selection were designed, though really they are not—just as water flows downhill as if it “wanted” to get to the bottom, though of course it doesn’t really “want” anything at all. Talk of evolution “designing” things, like talk of what water “wants,” can only be metaphorical.

The trouble is that Dennett’s entire edifice makes sense only if it is not metaphorical. For example, like other materialists, Dennett models the mind on the idea of the computer. But computers are the products of human designers. Hence it makes no sense to try to explain the mind in terms of computers, since the existence of a computer itself presupposes the existence of a designing mind. Dennett’s way of dealing with this problem is to say that the human minds or “computers” that design computers in the ordinary sense are themselves designed in turn by evolution. But again, evolution doesn’t literally “design” anything, so this is no answer to the problem at all. It only seems to be an answer if we fail to distinguish the literal and metaphorical senses of the word “design.”

Dennett thrives on such ambiguity and imprecision. Consider the use he makes of fellow celebrity atheist Richard Dawkins’s notion of a “meme,” which is a cultural artifact (such as an idea, a phrase, or a behavioral pattern) passed on from mind to mind the way a gene is passed down from generation to generation. Dennett argues that the origin of the human mind can be found in the evolutionary competition between memes, his favorite examples of which are words. Human thought is the end result of a long chain of events that began when words “invaded” brains, and some of them ended up reproducing themselves more effectively than others.

* * *

Dennett addresses various objections to this approach, but ignores the most glaring and serious problems. First, unlike genes (and like computers), words and other “memes” are human artifacts, the products of human convention. Apart from our custom of using a set of ink marks or sound waves as a word, these physical entities would be as utterly devoid of meaning or symbolic function as a random splotch of oil or dirt. The existence of words thus presupposes the existence of human minds, so that it makes no sense to try to explain the existence of human minds in terms of the preexistence of words. Dennett puts the cart before the horse so many times, he risks prosecution for animal abuse.

Furthermore, natural selection, whether among organisms or among “memes,” is sensitive to survival value alone. It “cares” nothing about the truth or falsity of our thoughts or the logical rigor of our arguments. If comforting falsehoods and fallacious reasoning happen to be conducive to our survival, then they will be selected for. They will seem right to us even if they are not. But then, if Dennett’s account of the origin of human thought processes were correct, we could have no reason to suppose that those processes track truth or conform to canons of logical inference. Again, they will appear to do so even if they do not. This undermines any confidence we could have in any idea or argument—including Dennett’s.

Dennett’s position is self-defeating in another way. He maintains that what philosopher Wilfrid Sellars called the “manifest image”—the world as it appears to us in everyday conscious experience (as opposed to the “scientific image,” or the world as represented by physics, chemistry, biology, and the like)—is a “user-illusion.” That is to say, our perceptual awareness of the external world is a set of convenient fictions that allows us to navigate a reality whose true nature is too complex for our brains to handle.

Now, there are at least two fatal paradoxes here, which Dennett does not even address, much less resolve. The first is that the human self or “user” is, in his view, itself part of the illusion. Hence there is no one there for the “illusion” to be an illusion for. Dennett’s account thus destroys the foundations of its own intelligibility. Second, natural science, in the name of which Dennett puts forward his various theories, ultimately rests on the empirical evidence provided by conscious experience. Hence if conscious experience really were a “user-illusion,” it would follow that the foundations of empirical science are illusory.

That would deprive Dennett of the rhetorical device which, next to shameless ambiguity, is his favorite—namely, the interminable rehearsal of what he’s been reading in the latest science literature. The ideas Dennett reports are sometimes interesting enough in themselves, but ultimately do nothing to support his own main contentions or solve the grave problems facing them. Their real function is to foster the impression that the dubious philosophical assertions he interposes between the pop science summaries are somehow themselves “scientific.”

* * *

Dennett’s third favorite rhetorical weapon, and the one he falls back on when the first two fail, is the vulgar abuse of those who disagree with him. Resistance to ideas like Dennett’s, he assures us, is not really motivated by science or sound philosophy but by “fear,” “pride,” and the “love of mystery.” It reflects “emotional turmoil” at the very thought that our inner lives might yield to scientific analysis. It has no arguments in its favor better than appeals to mere “intuition,” “ignorant fantasies,” “ancient myths,” or even “magic.” Dennett tells us that his critics simply find views like his “unsettling,” and he is correct to this extent: a steady barrage of begged questions, red herrings, non sequiturs, straw men, ad hominem attacks, and other transparent fallacies can indeed be unsettling, especially coming from a professional philosopher.

Dennett bemoans the legacy of what he calls “the Cartesian wound”—René Descartes’s famous bifurcation between mind and matter—without realizing how beholden to it he is himself. Descartes had, for the purposes of physics, redefined matter in entirely quantitative or mathematical terms. That is why he had to characterize the mind—which is the seat of qualitative features like the experience of a color, a sound, a pain, or a tickle—as immaterial. It is also why he drew a sharp distinction between the way nature appears to us in conscious experience and the way it really is. Dennett does not reject this set of basic assumptions. On the contrary, he insists that the difference between appearance and reality is even greater than Descartes said it was. Dennett is in fact an extreme Cartesian, rather than the anti-Cartesian he takes himself to be.

Having pulled the qualitative features of conscious experience out of the material world, Descartes relocated them in a non-physical substance. Dennett chucks out the non-physical substance, and the qualitative features of consciousness along with them. What would be truly revolutionary—and what Dennett never even considers—would be to reverse Descartes’s fundamental move and put qualitative features back into the material world. This would in no way require us to abandon the findings of modern mathematical physics. What it would require is merely the recognition that, while what physics tells us about the natural world is true, it is not the whole truth, but must be supplemented by philosophy.

* * *

The master fallacy that underlies Dennett’s entire book, however, is enshrined in the conceit that “many of the puzzles…of human consciousness evaporate once you ask how they could possibly have arisen—and actually try to answer the question!” What this means, the reader discovers, is that whenever Dennett finds some aspect of the mind that materialism cannot account for—design or purpose in the literal sense, the self, free will, meaning, subjective conscious experience—he concludes, not that materialism is false, but that the aspect in question must not be real after all.

For Daniel Dennett, what is real is only what materialism can explain. Materialism is true, he reasons, because it can explain everything there is to explain about the mind; and what it cannot explain must not really be there, he concludes, because materialism is true. From Bacteria to Bach and Back is Dennett’s demonstration that he can stay on this merry-go-round for hundreds of pages without getting dizzy.

Blood simply has to be somehow derivable from stone, you see, and if logic and evidence indicate otherwise, then logic and evidence must be wrong. Darwin famously described On the Origin of Species as “one long argument.” Dennett’s bloated tome is essentially one long circular argument.