Philosophy, Etienne Gilson observed, "always buries its undertakers." "Philosophy," according to Stephen Hawking and Leonard Mlodinow, in their new book The Grand Design, "is dead." It has "not kept up with modern developments in science, particularly physics, [and] scientists have become the bearers of the torch of discovery in our quest for knowledge." Not only, according to Hawking and Mlodinow, has philosophy passed away; so, too, has natural theology. At any rate, the traditional argument from the order apparent in the structure and operations of the universe to a transcendent cause of these, namely God, is wholly redundant--or so they claim: "[Just] as Darwin and Wallace explained how the apparently miraculous design of living forms could appear without intervention by a supreme being, the multiverse concept can explain the fine tuning of physical law without the need for a benevolent creator who made the Universe for our benefit. Because there is a law of gravity, the Universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the Universe exists, why we exist."
Notwithstanding their death notice for philosophy, in introducing their idea of a fundamental physical account of the universe, M-theory, the authors themselves cannot resist engaging in evident philosophizing about the nature of theories and their relationship to reality. To address the paradoxes arising from quantum physics, they use what they call "model-dependent realism," which "is based on the idea that our brains interpret the input from our sensory organs by making a model of the world."
When such a model is successful at explaining events, we tend to attribute to it, and to the elements and concepts that constitute it, the quality of reality or absolute truth. But there may be different ways in which one could model the same physical situation, with each employing different fundamental elements and concepts. If two such physical theories or models accurately predict the same events, one cannot be said to be more real than the other.
While a professional philosopher might disambiguate and refine some of these expressions and formulations, Hawking and Mlodinow are describing a position familiar within the philosophy of science and known variously as "constructive empiricism," "pragmatism," and "conceptual relativism." They are not replacing philosophy with science. Indeed, their discussion shows that, at its most abstract, theoretical physics leaves ordinary empirical science behind and enters the sphere of philosophy, where it becomes vulnerable to refutation by reason.
Certainly their argument from M-theory to the redundancy of the God hypothesis, for example, is open to direct philosophical criticism. If the necessary conditions of our existence did not obtain, we would not exist, and if the necessary conditions of the necessary conditions of our existence had not obtained, then neither we nor many other aspects and elements of the present universe would have been. Any scientific theory that is incompatible with things having been as they had to have been, in order for the universe to be as it is, is thereby refuted.
None of this may be very profound or took science to establish, but it does raise a question: Is the obtaining of the necessary conditions in question explicable, and, if so, how? What we know about the observable universe, and what we can infer about what is unobservable, indicate that it is composed of a number of types of entities and forces whose members exhibit common properties and are subject to a small number of simple laws.
There is nothing obviously inevitable about this fact. The universe could have been spatially and temporally chaotic. Yet it isn't. Chemistry tells us that elements share well-defined structural properties in virtue of which they can and do enter …