The Problem with Atheism

Many physicalists or naturalists insist that the argument from design is an outdated argument and claim that science can offer a better explanation. Nagel says not so fast:

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?

Nagel doesn't offer an answer but does argue that we should avoid a physically reductionist worldview:

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.

That is a lot of quotes, but you should read the whole thing. I found it intelligent and thought provoking.