The Grand Design, by Stephen Hawking and Leonard Mlodinow (Bantam, 199 pp., $28)
The English philosopher C. D. Broad once noted that “the nonsense written by philosophers on scientific matters is exceeded only by the nonsense written by scientists on philosophy.” You might think there could be no better illustration of Broad’s dictum than Richard Dawkins’s unhappy forays into the philosophy of religion. If so, you should take a look at the latest volume from Stephen Hawking and Leonard Mlodinow.
To be sure, the bulk of The Grand Design is devoted to a fairly lucid exposition of the central theories of modern physics. Had Hawking and Mlodinow stuck to science, there would have been little to object to. (Though also little reason to take notice. Did we really need yet another popular account of relativity, quantum mechanics, and string theory?) But they have grander ambitions: a new philosophy of science, in the service of a new theory of the origins of the universe, one that will forever put paid to the claims of natural theology. “Philosophy is dead,” Hawking and Mlodinow assure us, for science can now do what philosophers have tried to do, only better. Unfortunately, their attempt at one-upmanship proves only that Cicero’s famous quip about philosophers may have been misdirected; for The Grand Design demonstrates conclusively that there is nothing so absurd but some scientist has said it.
Before nemesis comes hubris, and in the case of Hawking and Mlodinow, that means a basic failure to grasp the philosophical ideas they airily dismiss. Like the village atheist whose knowledge of theology derives from what he saw last Sunday on The Jimmy Swaggart Telecast, our authors assume that when philosophers have argued for God as cause of the world, what they mean is that the universe had a beginning, that God caused that beginning, and that to rebut their position it suffices to ask “What caused God?” But from Aristotle to Aquinas to Leibniz to the present day, most versions of the First Cause argument have not supposed that the universe had a beginning in time, and none of them is open to so simple a refutation. Their claim is rather that even if the universe were infinitely old, it is still the sort of thing that might in principle not have existed at all. That it does exist therefore requires explanation, and this explanation cannot lie in some other thing that might in principle have failed to exist, since that would just raise the same problem again. Accordingly, the explanation can be found only in something that could not have failed to exist even in principle — something that not only does not have a cause, but couldn’t have had one, precisely because (unlike the universe) it couldn’t in theory have failed to exist in the first place. In short, any contingent reality, like the universe, must depend upon a necessary being, and this necessary being is what defenders of the First Cause argument mean by “God.”
Of course, there is much more to it than that — like a scientific theory, a complex philosophical argument cannot adequately be defended in the course of a book review written for a general audience — but Hawking and Mlodinow don’t even rise to the level of simplistic summary. And while an atheist might object to the argument in various ways, asking “What caused God?” simply misses the point. It is like asking “Why couldn’t a Euclidean triangle have sides that aren’t straight?” A triangle without straight sides just wouldn’t be a Euclidean triangle, and a “God” who could in principle have had a cause just wouldn’t be the sort of God that the First Cause argument is arguing for.
Even worse than their sophomoric treatment of natural theology, though, is what Hawking and Mlodinow propose to put in its place. In the course of their overview of quantum mechanics, they make heavy use of Richard Feynman’s “sum over histories” interpretation, according to which a particle in the famous double-slit experiment can be interpreted as taking every possible path on its way from its source to the screen opposite the slits. That much is unremarkable, though Feynman’s approach, like quantum mechanics in general, raises philosophical questions the possible answers to which remain (contrary to the impression given by Hawking and Mlodinow) matters of controversy. More dubious (though not unique to our authors) is the jump to the conclusion that our universe is really part of a “multiverse” or collection of parallel universes. But even that metaphysical extravagance is as nothing compared with the climax to which they build, after discussing the effects observation has on a quantum system: the pronouncement that “we create [the universe’s] history by our observation, rather than history creating us” and that since we are part of the universe, it follows that “the universe . . . create[d] itself from nothing.”
Their argument for this remarkable claim is, shall we say, rather sketchy. But the main problem with it is that it is simply incoherent, a metaphysical impossibility. Philosophers and scientists alike have for millennia acknowledged as a necessary truth the principle that nothing can be the cause of itself. The reason is that the very idea of something causing itself is self-contradictory: If a thing were to cause itself, it would have to exist prior to itself, in which case it would already exist and not need to be caused. (“Prior” need not entail “earlier in time”; the same incoherence arises even if we think of a cause and its effect as simultaneous, and interpret “prior to” as meaning “more fundamental than.”) Hawking and Mlodinow do not even acknowledge, much less attempt to answer, this traditional “self-contradiction” objection to the idea of self-causation — despite insisting on “consistency” as an essential criterion for any sound theory. This is the sober, scientific alternative to natural theology?
It gets worse, if that is possible. Our authors put forward as a novel philosophy of science something they call “model-dependent realism.” Judging from the name, you might expect that their position is a version of realism — the view that the entities described by scientific theories really exist objectively — and sometimes Hawking and Mlodinow write as if that is indeed what they think. Unfortunately, they also say things that contradict this. For example, in some contexts they tell us that where “physical theories or models accurately predict the same events, one cannot be said to be more real than the other; rather, we are free to use whichever model is most convenient” — which sounds like what philosophers of science call instrumentalism rather than realism. In other contexts they say that “mental concepts are the only reality we can know . . . a well-constructed model creates a reality of its own,” which appears to entail idealism, the view that all reality is mind-dependent. And in yet other contexts they give the impression that what model-dependent realism is really about is the idea that “we have to employ different theories in different situations,” and should not expect all correct scientific models to be reducible to physics. That sort of view can indeed be interpreted in a realist manner, but in that case it is as old as Aristotle and not novel at all. The trouble is that Hawking and Mlodinow simply provide us with no clear or consistent account of what model-dependent realism is supposed to be. And their overall argument trades on this ambiguity: Some of their claims require interpreting the relevant physics realistically, some require interpreting it instrumentally, and some may even require interpreting it idealistically. This is a textbook example of what logicians call the fallacy of equivocation.
Had they bothered to acquaint themselves with work done in the philosophy of science, they would have known that their views are not at all novel where they are defensible, and completely muddled where they are original. But while philosophers of science typically consider it a prerequisite to serious work in the field to master the science they comment on, Hawking and Mlodinow repeatedly and confidently pronounce upon philosophy without doing their homework. (Their asides on the history of philosophy, the problem of free will, and the mind-body problem are as embarrassingly amateurish as what they have to say about the philosophy of religion and the philosophy of science.) They ignore their critics too — some of the problems I’ve noted here can be found also in Hawking’s famous book A Brief History of Time, and were pointed out 20 years ago by philosopher William Lane Craig.
Embedded as they are in this fabric of errors, even the otherwise useful expositions of relativity, quantum mechanics, and string theory are bound to be highly misleading to the non-expert reader. What comes across like mad science is really just bad philosophy. Next time, fellas, stick to physics, and leave the metaphysics to the experts.
– Mr. Feser is the author of Aquinas: A Beginner’s Guide and The Last Superstition: A Refutation of the New Atheism.