Conclusion: Blogging Rosenberg's The Atheist's Guide to Reality

Naturalism and the Christian Faith

Rosenberg makes scientism the defining feature of naturalism. (I tend to agree, though I prefer to conjoin what he calls scientism with two substantive scientific claims about human beings: we are material beings, the product of blind natural selection, and to call this scientific naturalism. What Rosenberg refers to as scientism I think of as the epistemological preeminence of science, and I’d use the term “scientism” to denote the claim that scientific knowledge is the only knowledge. But this is just terminology; nothing important turns on it.)

Scientism (as Rosenberg deploys the term) then, is the claim that science is our best way of knowing in the sense that (1) Any other claim to know should be rejected if it is logically inconsistent with the well-confirmed theories of science, and (2) any claim to scientific knowledge must cohere with what science tells us of the nature and capabilities of human minds, i.e., as brains that are products of natural selection and embedded in their particular natural and cultural environments.

Rosenberg, of course, believes that God does not exist and that the belief that he does exist is totally unreasonable. The point I want to stress here is that whatever his reasons for this conviction, his scientism has literally no bearing on it. Scientism, and thus naturalism, as he understands it, is entirely consistent with theism. That theism and scientism are consistent in the narrow sense of there being no contradiction in believing both is, I assume, too obvious to be worth defending. No well-confirmed scientific theory refers to God and, while it is conceivable that in conjunction with other things we know a well-confirmed theory implies that there is no God, plainly no such things are in the offing.

Although I don’t think this claim requires a serious defense, a case that is in some respects parallel seems worth noticing. Those who accept scientism remain in need of some sort of account of mathematics. Some naturalists—Quine is the salient example—deny the fundamental difference between mathematical and scientific truth and regard the truths of mathematics as differing from those of the natural sciences only with respect to their extreme generality. They dispense with the traditional view that the truths of mathematics are necessary while those of the sciences are contingent. Those who do not, and think that mathematics differs from science in a categorical way, agree that science is our best way of knowing but with an implicit scope restriction: it is our best way to know contingent reality, but mathematics as a way of knowing is epistemologically superior to science. In the event that a well-confirmed scientific theory conflicts with a theorem of mathematics, then it is unreasonable to believe science. Science trumps any competing claim about the contingent natural world, but mathematics trumps science. This is so obvious as to be unremarkable: hypotheses that have false mathematical implications are rejected out of hand; they’re not worthy of empirical testing. Naturalists who adhere to the contingent science/necessary mathematics distinction owe an account of the ground of mathematical truth and the roots of our mathematical knowledge, one that coheres with scientific knowledge in the two ways built into Rosenberg’s definition of scientism. One familiar form an account can take is mathematical Platonism, the idea that mathematical knowledge is knowledge of a transcendent, non-empirical realm of mathematical objects. I don’t believe this, and I don’t think it coheres in plausible ways with theism, but Platonists believe that they possess good reasons to believe it, e.g., that it best explains the nature of mathematical truth and discovery, or that it best explains the (to some) amazing applicability of mathematics to the description of the natural world. At face value, whatever the force of these reasons, they do not appear to be at odds with the well-confirmed theories of science, which are to all appearances silent on the metamathematical issues. Mathematical Platonism’s belief that there is a categorically different reality beyond the world science accesses is not incompatible with scientism. Nor is the theist’s analogous belief that there is a deity.

However, the theist is in a more comfortable position vis-à-vis naturalism than the mathematical Platonist. The latter faces a fairly serious problem of how the human mind can know anything about the mathematical objects his theory postulates. On the plausible assumption that these eternal non-physical realities are causally inert they can have no effect on the physical world and the evolved material minds it contains. This constrains the possibility of knowing it in ways analogous to perception, which, as it happens, is often embraced by Platonists as a way to conceive mathematical intuition. The Platonist is more at home with the anti-naturalist dualist view of the mind as transcending physical reality. The theist (assuming that he dispenses, as he ought, with divine timelessness and immutability) has no parallel problem: if there is a God then he can make things happen in the material world and reveal himself to the likes of us. We have no need to posit powers of mind foreign to scientific knowledge of our evolved brains. Mathematical Platonists and theists can accept Rosenbergian scientism (and naturalism), but it’s easier for the theist. There are, or might be, good reasons to believe in realities beyond the ken of the sciences, and to believe so is not at odds with scientific naturalism.

Anyway, the interesting question is not about the logical consistency of science and theism, but whether what science tells us about the world is at all likely on the supposition that God exists. If what science describes is a world not much like any world theists could reasonably anticipate, then theism is unreasonable. I assume that Rosenberg, and many others happy to call themselves naturalists, assume that:

Prob(S|G) = low

Where S is our scientific knowledge of the world and G is theism. But there is no reason to believe this. So far as bare, generic theism goes, with no specification as to the nature of God or the reasons for which he creates

Prob(S|G) = imponderable.

If we think there is a God but have nothing further to say about him we have no basis for regarding the claims of science as either likely or unlikely. All we can say is that

Prob(S|G) ≠ 0

i.e., God could have created a world exactly like the one science reveals to us.

Once we add beliefs about God, we can easily get the low-probability judgment, e.g., if we believe not just that God exists but that he would have designed the human species, then

Prob(S|G & D) = very low (if not 0).

As we have seen, Rosenberg (along with any number of theists) believes that this is a relevant judgment of prior probability, and it is, obviously, one on which theism comes out as not cohering with science, and thus as showing that there is no God. But should those of us who believe G also believe D? Does theism (of the type we take to be true) really imply divine design? On my view it does not. This is one of the ways in which a consideration not of generic theism, but of the particularities of biblical, Christian theism, brings us to a quite different conclusion about science: the world science describes is the kind of world we could have reasonably expected to find, assuming that the God of Christian faith is its creator. The crucial claim, not defended here, is that that God would not have chosen to design his creatures, but to bring them into existence by means of natural processes of the kind science describes.

0. Underlying Rosenberg’s project is the claim, made but not defended, that science reveals that God does not exist. Obviously, no well-confirmed theory of empirical science implies anything about God and thus science implies nothing about God’s alleged non-existence. Rosenberg assumes that if there were good reasons to believe that God exists, they would reside in theistic explanations of things that in fact science explains better. This is one of many false beliefs he shares with religious fundamentalists. However, Rosenberg can hardly be blamed for taking so many Christian theists at their word when they insist that what contemporary science tells us of the world and our place in it is antecedently improbable from the perspective of the Christian faith. They are wrong about this: the naturalistic implications of science are antecedently probable on Christian theology. But it’s not Rosenberg’s job to figure that out.

1. On Rosenberg’s account introspection reveals little or nothing of explanatory relevance about the human mind/brain because conscious states (a) are (something like) epiphenomenal, (b) no more than post hoc rationalizations of the unconscious goings on in the brain that actually cause human behavior, and (c) lack intentionality so they aren’t about anything anyway. Indeed, unconscious mental states, those that do cause behavior, also lack intentionality. There are experimental results (famously Libet’s) that support (a) and (b), though there’s plenty of distance from this evidence to these sweeping conclusions. The status of deflationary claims about intentionality, or to change the idiom, about the mind/brain having no semantic properties, is a central issue in the philosophy of the last century. I take it that all physicalists take it for granted that the facts about meaning are ontologically superficial, that in some sense the brain is a syntactic device that simulates a physically impossible semantic device. Where the mainstream sees this as setting the task of locating meaning in the world science knows, Rosenberg sees it as reason to elimiate serious talk of meaning. This is a manifestation of a general strategy, see #4, infra.

It would be nice to see at least a gesture toward the obvious issues of self-reference that arise from the claim that none of our thoughts are about anything. How do we manage to have scientific knowledge when our scientific beliefs are not about the world that makes science true?

2. Physics, Rosenberg reasonably asserts, fixes all the facts. (We theists who agree of course acknowledge an implicit scope restriction: physics fixes all the facts about the created world.) However, he appears to slide effortlessly from this to the stronger claim that all the facts are physical facts, or at least that all the facts are physical facts or facts reducible to physical facts. Most humanly important “facts,” e.g., those of folk-psychology or morality, thus turn out not to be facts at all. Here, as in other places, Rosenberg’s claims seem finely balanced between interpretations on which they are true but uncontroversial and interpretations on which, if not false, they are at least very controversial.

3. On the epistemological side there’s a similar move from the true, “Science is our best way of knowing,” to the highly problematic, “Science is our only way of knowing.” Such inferential leaps are all too familiar, but surely they are not mere mistakes on Rosenberg’s part. His texts in the philosophy of science are admirably clear and carefully reasoned introductions to many of the subjects he addresses in An Atheist’s Guide. The main disappointment of this book is that it seems to have been written by someone else! Writing, or trying to write, for a popular audience, one cuts all kinds of philosophical corners, and we see this going on left and right in An Atheist’s Guide. Yet it often seems that the wrong corners have been cut and that the effect on the philosophically innocent reader might well be the opposite of what Rosenberg intends: to instill the idea that the implications of taking science seriously are simply crazy. (I’m tempted to blame some editor’s notion of what’s appropriate for a book buying public.)

4. Along the way I’ve complained about Rosenberg’s strategy of reasoning from the fact that nothing in the reality known to science precisely answers to a familiar human concept, e.g., meaning, freedom, purpose, to the conclusion that that concept applies to nothing and should be eliminated from serious thought about the world. Why in at least some of these cases isn’t it more reasonable to regard our concepts as being corrected and revised by science and thus accorded their secure place in the world? We need not suppose that our pre-scientific concepts are infinitely malleable, but it’s hard to accept that they cannot sometimes be retained in versions improved by the encounter with science. And this is especially hard to accept in instances where the concepts at issue are adaptations that enable us to navigate the natural or social environment. But, of course, if all the facts are facts of (and not just fixed by) physics, there’s no place for such things in reality.

Here it’s worth pointing out Rosenberg’s reliance on folk-philosophical conceptions as though they are in perfectly good order. For example, he regularly tells us that since science shows that human behavior is causally determined, we are not free. But, of course, this is valid only with the addition of the premise that no causally determined action can be free. That premise remains unreflectively embraced by many, including many of the scientifically well-informed, and it might be true. The centuries of philosophical attack on it may be misguided. But the mere fact that this seems simply obvious to so many is no more a good reason to accept it than, say, the still-popular belief that heavy objects fall faster than light objects…or that our choices cause our actions.

5. An abiding question is about the supposed connection of all this—Rosenberg’s radically eliminative materialism—to atheism. Does he think that run of the mill naturalistic philosophers, engaged in the project of trying to explain how mind, rationality, meaning, purpose, freedom, and so on might fit into the physical universe best known by way of the sciences are some sort of crypto-theists, clinging to concepts that make sense only if there is a God? It would be interesting to see a case for that. (Perhaps Rosenberg and folks like Al Plantinga are on the same page: if no God then no meaning, no rationality, etc.) Insofar as anything like this appears in An Atheist’s Guide to Reality, it seems to be no more than one more fast inference, this one from the fact that there is no purpose in nature to the further claim that there is no purpose for nature. (For Rosenberg the claim that there is no purpose in nature encompasses not just the obvious fact that there is no final causation in nature, that evolution’s trajectory is blind, and that the etiology of human action is entirely a matter of efficient causation, but the not at all obvious claim that human beings do not really do things for reasons, i.e., that beliefs and desires are not the causes of behavior.)