GOD?

The tradition of "great debates" about the existence of God is by now well established (a famous early example was the discussion between Bertrand Russell and Frederick Copleston, broadcast in 1948 on the Third Programme of the BBC). The present volume, by two heavyweight analytic philosophers, is rather different from the usual pattern, in that it does not plough through the various standard arguments for God's existence. Instead, Alvin Plantinga, America's foremost philosopher of religion, puts the other side into bat, and opens the bowling with a formidable attack on the atheist world view.

His target is "naturalism", which has a good claim to be the dominant ideology among most philosophers and scientists working today. Naturalism is the denial of any supernatural (often pejoratively called "spooky") entities, including principally God, but also things like immaterial souls. The naturalist programme, which now occupies considerable numbers of philosophers, is the attempt to explain everything there is (including consciousness, language, knowledge, meaning, and morality) without recourse to the supernatural.

Plantinga has three arguments which purport to show that naturalism is unacceptable.

First, he claims that it cannot give an account of the idea of proper function, which is basic to our understanding of the biological world. Proper function is something that applies to an organism that is healthy, sound, and whose parts are in good working order. But naturalistic explanations of the biological world (such as those based on random mutation and natural selection) cannot, Plantinga thinks, justify such notions. "The notion of proper function really applies only to things that have been designed by purposeful, intelligent agents."

The argument is developed in great detail, which there is no space to explore here. But unfortunately it appears open to objections. Aristotle, in his biological and philosophical writings, provides what seems a perfectly satisfactory account of function without invoking the idea of intelligent design. It is, however, true that his account is what philosophers now call normative; it involves evaluative notions such as what is good for something. And it is not clear that naturalists can explain how the notion of the normative arises in a purely material cosmos.

Plantinga's second argument focuses on the philosophy of knowledge, as much of his work elsewhere has done. He suggests that naturalism leads to a virulent form of scepticism, since it gives us no reason for supposing that our belief-forming mechanisms are likely to be reliable. His third and final argument insists that naturalism, or at least materialism, cannot even account for the existence of

beliefs in the first place. For a belief is always about something, and so has a certain content. Yet drawing on an argument first presented by Leibniz in the eighteenth century, Plantinga argues that on the materialist supposition that beliefs are purely material and mechanical (e.g. neurological events of some kind), it is impossible to see "how a group of material objects firing away has a content".

Michael Tooley (who has some very powerful objections to raise against all three of Plantinga's arguments) opens his own innings, on behalf of the atheist, by deploying that most ancient of obstacles to theism, the problem of evil. Tooley's position is that although the existence of an all-powerful, all-knowing and perfectly good creator might be very "desirable", unfortunately, given the long list of the preventable pain, misery and suffering that the world contains, it is exceedingly unlikely that such a being exists. This basic line of thought is a straightforward and quite familiar one, although, like much contemporary analytic philosophy, the detail is worked out in a very intricate way (including technical calculations of inductive probabilities) that non-specialists will find indigestible.

Plantinga's response to Tooley is interesting because it shows the extent to which the current debate over the so-called "probabilistic" version of the problem of evil referred to above has become a stand-off: no one is about to change their minds. A believer, argues Plantinga, is one whose faith is firmly grounded in a sensus divinitatis, a sense of the presence of God in the world. Such a person may be appalled at the horrifying evils the world contains, deeply perplexed at God's role in permitting them, perhaps even angry and resentful; but "needn't entertain for a moment the belief that there is no such person as God".

There is an implicit and important lesson here about the limits of philosophical argument. When God appears to Job out of the whirlwind, "the point is not really to convince him that God has his reasons, but to quiet him, to still the storm in his soul ... [so that] the doubts and turmoil abate and once more Job loves and trusts the Lord". It is a paradox, but a pleasing one, that a volume premised on the value of meticulous philosophical debate ends by indicating where rational discussion must end.