When philosophers speak of the inconclusiveness of arguments for the existence of God, they often do so as if they were talking about a matter of principle—as if it were in principle impossible to prove God's existence, that every proof was in principle inconclusive. Of course, rebutals of the cosmological, ontological, and teleological arguments are usually designed to show that these types of arguments are in principle inconclusive. But one supposes (initially at least) that religious experience arguments are not all in such difficulties. That is, one supposes, for example, that an encounter with the deity would provide a proof of his existence which is at least as conclusive as proofs for the existence of an ‘external world’. And thus it would be false to maintain in an unqualified way that ‘Reason cannot (in principle) prove the existence of God’. The most one would be able to say would be that at present, or in terms of the currently available evidence, no one can prove God's existence. Further, whether or not sufficient evidence has ever been available in the past would be seen as an historical question— a matter of contingencies, not logical possibilities.