ALL JUST FOOTNOTES TO HUME:

But can't the new atheists simply help themselves to the premise that science is the only source of knowledge? We might wonder on what basis they could: surely it is not a claim of science that science is the only source of knowledge. But this, as we will see, is only one way in which extreme naturalism threatens to be its own worst enemy.

In the third part of the book, Plantinga turns to the question of whether in fact theism might be in concord with contemporary science, rather than in conflict. After looking at, and giving a fairly weak endorsement to, some arguments in support of intelligent design and fine-tuning, Plantinga argues that in fact the theistic worldview is as a whole deeply consonant with the goals and successes of contemporary science.

This is because theism holds, as atheistic naturalism denies, that God has created us in his image, as rational beings. But as rational, yet finite, beings, we are truth-seekers, and for the theist it makes perfectly good sense to think that God has also created a world that is available to us to know: "God created both us and our world in such a way that there is a certain fit or match between the world and our cognitive faculties."

Plantinga then identifies a number of features of our world, and our cognitive relationship to that world, that are much more likely, and make much more sense, on a theistic than on an atheistic picture: the reliability and regularity of nature, and its working in accordance with law; the role of mathematics in the understanding of nature; the possibility of induction; the appropriateness of theoretical virtues such as simplicity; and even the empirical nature of science, which Plantinga argues is underwritten by the contingency of divine creation. In all these respects modern science is deeply compatible with theism, a fact that renders unsurprising the further fact that all the great founders of modern science were theists, working from a deeply Christian background.

So the conflict between science and religion is, Plantinga shows, largely bogus (and I have only scratched the surface of his arguments here). But things are even worse from the standpoint of naturalism, for on the naturalist account, there is no good reason to think that our cognitive faculties are truth-tracking. After all, it is not because those faculties contribute to true beliefs that they are selected for in the Darwinian account; it is because they are likely to contribute to survival.

Can the naturalist expect, as the theist clearly can, that her cognitive faculties are reliable, i.e., that they lead to true beliefs? Since natural selection does not select for truth, or truth-tracking faculties, but for other unrelated properties, we have no reason to expect so given naturalism. Of course, we have very good reason to think our beliefs are reliable; so this claim should not bother most people. And non-naturalistic theists will believe that even if evolution is true, God has overseen evolution with a view to the reliability of our cognitive faculties. The naturalist cannot rely on any such claim.

But since the inability to rely on cognitive faculties as reliably truth-tracking is a defeater for any belief whatsoever, it is a defeater also for naturalism; accordingly naturalism turns out, on Plantinga's argument, to be self-defeating, and cannot be rationally accepted.

Follow @brothersjudd