‘...the whole process of human thought, what we call Reason, is ... valueless if it is the result of irrational causes. Hence every theory of the universe which makes the human mind a result of irrational causes is inadmissible, for it would be a proof that there are no such things as proofs. Which is nonsense. But Naturalism, as commonly held, is precisely a theory of this sort.’ Thus C. S. Lewis, in the first edition of Miracles. Forceful objections from Elizabeth Anscombe led Lewis to drop this passage from the second edition of his book. But even there he still clung to the general idea that while theism involves no such difficulty Naturalism somehow defeats itself: ‘...our conviction that Nature is uniform ... can be trusted only if a very different Metaphysic is true. If the deepest thing in reality, the Fact which is the source of all other facthood, is a thing in some degree like ourselves – if it is a Rational Spirit and we derive our rational spirituality from It – then indeed our conviction can be trusted. Our repugnance to disorder is derived from Nature's Creator and ours.’ Similar claims have frequently been made by Lewis's supporter Stephen Clark. In a typical passage Clark insists that ‘if we are to be able to trust our seeming capacity to understand the world, we must suppose that our minds mirror or share in the pattern and life which is the foundation of the world’. And now, in the last chapter of his Warrant and Proper Function, Alvin Plantinga has endorsed and developed what he duly acknowledges to be Lewis's idea. Plantinga does not pretend to have formulated a totally cogent argument for Naturalism's self-defeat. But he does think that he has said enough to indicate ‘a promising research program’. In what follows I scrutinize the argument which he sketches out.

It is sometimes held that there is something in the very nature of religious pluralism that undermines the rationality of religious belief. This view, I am happy to note, is beginning to receive the sort of attention it deserves from philosophers of religion. Various arguments from religious pluralism against religious belief have recently been canvassed. But in all this activity, as in the relevant historical discussions, one argument – a probabilistic argument from pluralism – seems largely to have escaped notice. In what follows I develop and discuss a version of the argument, and give an estimate of its force. As I hope to show, it is not an argument to be taken lightly.

In ‘The Impossibility of a Pluralist View of Religions’ (Religious Studies 32, June 1996) Gavin D'Costa argues that ‘pluralism must always logically be a form of exclusivism and that nothing called pluralism really exists’ (225). He sees himself as doing a ‘conceptual spring cleaning exercise’ (225). However the result is to obscure clear and useful distinctions by confused and confusing ones. Some further spring cleaning is therefore called for.

The religious pluralism that D'Costa is referring to is the view that the great world religions constitute conceptually and culturally different responses to an ultimate transcendent reality, these responses being, so far as we can tell, more or less on a par when judged by their fruits. And the religious exclusivism to which he refers holds that one particular religion – in his case Christianity – is alone fully true and salvific, the others being either wholly misleading, or inferior imitations of or inferior approximations to the one ‘true’ religion.

William Lane Craig has given an extended defence of the following version of the Cosmological Argument for the existence of God:

Since everything that begins to exist has a cause of its existence, and since the universe began to exist, we conclude, therefore, that the universe has a cause of its existence. We ought to ponder long and hard over this truly remarkable conclusion, for it means that transcending the entire universe there exists a cause which brought the universe into being ex nihilo ... we may plausibly argue that the cause of the universe is a personal being.

This ‘Kalam’ version of the Cosmological Argument may be laid out formally as follows:

(i) The universe began to exist.

(ii) Everything which begins to exist has a cause. (The Causal Principle.)

(iii) Therefore the universe had a cause.

Much recent Kierkegaard scholarship has paid particular attention to various aspects of the literary form of his authorship, such as the significance of his writing under various pseudonyms. The focus has been upon ‘style’ as much as ‘content’; the ‘how’ as much as the ‘what’ of Kierkegaard's writing. Within this context, James Conant has argued, in a series of articles, that there are important parallels between the Concluding Unscientific Postscript (authored by the Kierkegaardian pseudonym Johannes Climacus) and Wittgenstein's Tractatus. However, Conant argues that these parallels have been misunderstood by previous commentators. The main aim of this article is to challenge Conant's argument that the Postscript should be read as containing ‘nonsense...simple, old garden variety nonsense’. This, we shall see, relies upon a particular view of the significance of Climacus's ‘revocation’ of the text. The commentators whom Conant wants to criticize allegedly hold that the Tractatus and the Postscript provide ‘essential preliminary noise’ to the realization that those issues which really matter – in particular, ethics and religion – cannot be spoken of. These commentators, according to Conant, insist on the existence of a kind of speech ‘that lacks sense while still being able to convey volumes’.

An honest religious thinker is like a tightrope walker. He almost looks as though he were walking on nothing but air. His support is the slenderest imaginable. And yet it really is possible to walk on it.

Nicholai Hartman suggested the well-known distinction between ‘systematic thinking’ and ‘problem thinking’. Whereas the former begins from a series of assumptions and proceeds to offer all-encompassing solutions, the latter begins from a problem and considers it in depth, without striving for comprehensive systems. Problem thinking is dialectical – it appraises the boundaries of the problem and the limitations of its solutions. According to Hartman, a typical instance of a systematic thinker is Spinoza, who created an inclusive metaphysical system based on primary and irrefutable assumptions. A classic example of problem thinking is the philosophy of Plato, which is more intent on clarifying the predicament than on offering solutions, and hence its dialectic character.

John Hick offers a summary account of William James's ‘The Will to Believe’ which is typical of the way that this essay has been understood by many in the one hundred years since it was first published. According to Hick, James argues

that the existence or nonexistence of God, of which there can be no conclusive evidence either way, is a matter of such momentous importance that anyone who so desires has the right to stake one's life upon the God hypothesis.