Wednesday, November 01, 2006

The fear of religion

Thomas Nagel is one of the world’s leading secular philosophers. Yet his evident predisposition to sympathize with Richard Dawkins makes the way in which he pans the new book all the more devastating. Here are some excerpts of the review:

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The Fear of Religion
by Thomas Nagel

Richard Dawkins, the most prominent and accomplished scientific writer of our time, is convinced that religion is the enemy of science. Not just fundamentalist or fanatical or extremist religion, but all religion that admits faith as a ground of belief and asserts the existence of God. In his new book, he attacks religion with all the weapons at his disposal, and as a result the book is a very uneven collection of scriptural ridicule, amateur philosophy, historical and contemporary horror stories, anthropological speculations, and cosmological scientific argument. Dawkins wants both to dissuade believers and to embolden atheists.

Since Dawkins is operating mostly outside the range of his scientific expertise, it is not surprising that The God Delusion lacks the superb instructive lucidity of his books on evolutionary theory, such as The Selfish Gene, The Blind Watchmaker, and Climbing Mount Improbable. In this new book I found that kind of pleasure only in the brief explanation of why the moth flies into the candle flame--an example introduced to illustrate how a useful trait can have disastrous side effects. (Dawkins believes the prevalence of religion among human beings is a side effect of the useful trust of childhood.).

In a previous chapter, Dawkins dismisses, with contemptuous flippancy the traditional a priori arguments for the existence of God offered by Aquinas and Anselm. I found these attempts at philosophy, along with those in a later chapter on religion and ethics, particularly weak; Dawkins seems to have felt obliged to include them for the sake of completeness. But his real concern is with the argument from design, because there the conflict between religious belief and atheism takes the form of a scientific disagreement--a disagreement over the most plausible explanation of the observable evidence. He argues that contemporary science gives us decisive reason to reject the argument from design, and to regard the existence of God as overwhelmingly improbable..

The first difference is not an objection to the argument. Scientific inference to the best explanation of what we can observe often leads to the discovery of things that are themselves unobservable by perception and detectable only by their effects. In this sense, God might be no more and no less observable than an electron or the Big Bang. But the second difference is more troubling, since it is not clear that we can understand the idea of purposive causation--of design--by a non-physical being on analogy with our understanding of purposive causation by a physical being such as a watchmaker. Somehow the observation of the remarkable structure and function of organisms is supposed to lead us to infer as their cause a disembodied intentional agency of a kind totally unlike any that we have ever seen in operation.

Still, even this difference need not be fatal to the theistic argument, since science often concludes that what we observe is to be explained by causes that are not only unobservable, but totally different from anything that has ever been observed, and very difficult to grasp intuitively. To be sure, the hypothesis of a divine creator is not yet a scientific theory with testable consequences independent of the observations on which it is based. And the purposes of such a creator remain obscure, given what we know about the world. But a defender of the argument from design could say that the evidence supports an intentional cause, and that it is hardly surprising that God, the bodiless designer, while to some extent describable theoretically and detectable by his effects, is resistant to full intuitive understanding.

Dawkins's reply to the argument has two parts, one positive and one negative…The negative part of the argument asserts that the hypothesis of design by God is useless as an alternative to the hypothesis of chance, because it just pushes the problem back one step. In other words: who made God? "A designer God cannot be used to explain organized complexity because any God capable of designing anything would have to be complex enough to demand the same kind of explanation in his own right."

Let me first say something about this negative argument. It depends, I believe, on a misunderstanding of the conclusion of the argument from design, in its traditional sense as an argument for the existence of God. If the argument is supposed to show that a supremely adept and intelligent natural being, with a super-body and a super-brain, is responsible for the design and the creation of life on earth, then of course this "explanation" is no advance on the phenomenon to be explained: if the existence of plants, animals, and people requires explanation, then the existence of such a super-being would require explanation for exactly the same reason. But if we consider what that reason is, we will see that it does not apply to the God hypothesis.

The reason that we are led to the hypothesis of a designer by considering both the watch and the eye is that these are complex physical structures that carry out a complex function, and we cannot see how they could have come into existence out of unorganized matter purely on the basis of the purposeless laws of physics. For the elements of which they are composed to have come together in just this finely tuned way purely as a result of physical and chemical laws would have been such an improbable fluke that we can regard it in effect as impossible: the hypothesis of chance can be ruled out. But God, whatever he may be, is not a complex physical inhabitant of the natural world. The explanation of his existence as a chance concatenation of atoms is not a possibility for which we must find an alternative, because that is not what anybody means by God. If the God hypothesis makes sense at all, it offers a different kind of explanation from those of physical science: purpose or intention of a mind without a body, capable nevertheless of creating and forming the entire physical world. The point of the hypothesis is to claim that not all explanation is physical, and that there is a mental, purposive, or intentional explanation more fundamental than the basic laws of physics, because it explains even them.

All explanations come to an end somewhere. The real opposition between Dawkins's physicalist naturalism and the God hypothesis is a disagreement over whether this end point is physical, extensional, and purposeless, or mental, intentional, and purposive. On either view, the ultimate explanation is not itself explained. The God hypothesis does not explain the existence of God, and naturalistic physicalism does not explain the laws of physics.

To be sure, this is only the schema for an explanation. Most of the details of the story can never be recovered, and there are many issues among evolutionary biologists over how the process works. There are also skeptics about whether such a process is capable, even over billions of years, of generating the complexity of life as it is. But I will leave those topics aside, because the biggest question about this alternative to design takes us outside the theory of evolution.

It is a question that Dawkins recognizes and tries to address, and it is directly analogous to his question for the God hypothesis: who made God? The problem is this. The theory of evolution through heritable variation and natural selection reduces the improbability of organizational complexity by breaking the process down into a very long series of small steps, each of which is not all that improbable. But each of the steps involves a mutation in a carrier of genetic information--an enormously complex molecule capable both of self-replication and of generating out of surrounding matter a functioning organism that can house it. The molecule is moreover capable sometimes of surviving a slight mutation in its structure to generate a slightly different organism that can also survive. Without such a replicating system there could not be heritable variation, and without heritable variation there could not be natural selection favoring those organisms, and their underlying genes, that are best adapted to the environment.

The entire apparatus of evolutionary explanation therefore depends on the prior existence of genetic material with these remarkable properties. Since 1953 we have known what that material is, and scientists are continually learning more about how DNA does what it does. But since the existence of this material or something like it is a precondition of the possibility of evolution, evolutionary theory cannot explain its existence. We are therefore faced with a problem analogous to that which Dawkins thinks faces the argument from design: we have explained the complexity of organic life in terms of something that is itself just as functionally complex as what we originally set out to explain. So the problem is just pushed back one step: how did such a thing come into existence?

Of course there is a huge difference between this explanation and the God hypothesis. We can observe DNA and see how it works. But the problem that originally prompted the argument from design--the overwhelming improbability of such a thing coming into existence by chance, simply through the purposeless laws of physics--remains just as real for this case. Yet this time we cannot replace chance with natural selection.

Dawkins recognizes the problem, but his response to it is pure hand-waving. First, he says it only had to happen once. Next, he says that there are, at a conservative estimate, a billion billion planets in the universe with life-friendly physical and chemical environments like ours. So all we have to suppose is that the probability of something like DNA forming under such conditions, given the laws of physics, is not much less than one in a billion billion. And he points out, invoking the so-called anthropic principle, that even if it happened on only one planet, it is no accident that we are able to observe it, since the appearance of life is a condition of our existence.

Dawkins is not a chemist or a physicist. Neither am I, but general expositions of research on the origin of life indicate that no one has a theory that would support anything remotely near such a high probability as one in a billion billion. Naturally there is speculation about possible non-biological chemical precursors of DNA or RNA. But at this point the origin of life remains, in light of what is known about the huge size, the extreme specificity, and the exquisite functional precision of the genetic material, a mystery--an event that could not have occurred by chance and to which no significant probability can be assigned on the basis of what we know of the laws of physics and chemistry.

Yet we know that it happened. That is why the argument from design is still alive, and why scientists who find the conclusion of that argument unacceptable feel there must be a purely physical explanation of why the origin of life is not as physically improbable as it seems. Dawkins invokes the possibility that there are vastly many universes besides this one, thus giving chance many more opportunities to create life; but this is just a desperate device to avoid the demand for a real explanation.

I agree with Dawkins that the issue of design versus purely physical causation is a scientific question. He is correct to dismiss Stephen Jay Gould's position that science and religion are "non-overlapping magisteria." The conflict is real. But although I am as much of an outsider to religion as he is, I believe it is much more difficult to settle the question than he thinks. I also suspect there are other possibilities besides these two that have not even been thought of yet. The fear of religion leads too many scientifically minded atheists to cling to a defensive, world-flattening reductionism. Dawkins, like many of his contemporaries, is hobbled by the assumption that the only alternative to religion is to insist that the ultimate explanation of everything must lie in particle physics, string theory, or whatever purely extensional laws govern the elements of which the material world is composed.

This reductionist dream is nourished by the extraordinary success of the physical sciences in our time, not least in their recent application to the understanding of life through molecular biology. It is natural to try to take any successful intellectual method as far as it will go. Yet the impulse to find an explanation of everything in physics has over the last fifty years gotten out of control. The concepts of physical science provide a very special, and partial, description of the world that experience reveals to us. It is the world with all subjective consciousness, sensory appearances, thought, value, purpose, and will left out. What remains is the mathematically describable order of things and events in space and time.

That conceptual purification launched the extraordinary development of physics and chemistry that has taken place since the seventeenth century. But reductive physicalism turns this description into an exclusive ontology. The reductionist project usually tries to reclaim some of the originally excluded aspects of the world, by analyzing them in physical--that is, behavioral or neurophysiological--terms; but it denies reality to what cannot be so reduced. I believe the project is doomed--that conscious experience, thought, value, and so forth are not illusions, even though they cannot be identified with physical facts.

I also think that there is no reason to undertake the project in the first place. We have more than one form of understanding. Different forms of understanding are needed for different kinds of subject matter. The great achievements of physical science do not make it capable of encompassing everything, from mathematics to ethics to the experiences of a living animal. We have no reason to dismiss moral reasoning, introspection, or conceptual analysis as ways of discovering the truth just because they are not physics.

Any anti-reductionist view leaves us with very serious problems about how the mutually irreducible types of truths about the world are related. At least part of the truth about us is that we are physical organisms composed of ordinary chemical elements. If thinking, feeling, and valuing aren't merely complicated physical states of the organism, what are they? What is their relation to the brain processes on which they seem to depend? More: if evolution is a purely physical causal process, how can it have brought into existence conscious beings?

http://www.tnr.com/docprint.mhtml?i=20061023&s=nagel102306

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