His own use of evidence in the field of religion is, given his general insistence on its importance, remarkably cavalier.  Thus, the pilgrims at Lourdes are described as 'desperate people', and this despite the totally non-fanatical balanced affability of the two women he interviewed; he does not apparently think he needs evidence for saying that Bernadette was 'impressionable'; or, if he has any, he does not tell us.

Perhaps he simply assumes that believers must be so.  He likewise assumes, this time despite abundant evidence to the contrary, that all believers will either deny the theory of evolution altogether, or will have to assume that God constantly needs to interfere with creation, to lend a 'helping hand' (as Dawkins put it) to keep evolution going.

The existence of God was asserted to be 'improbable', this time without even argument let alone evidence.  Religion, Dawkins claims, requires believers to abandon reason in favour of a 'comforting faith'.  Such breathtaking ignorance of, or wilful disregard for, the history of theology is explicable only if Dawkins himself has made his mind up about religion - any and all religion - in advance of any sympathetic attempt to understand a view before one claims to have refuted it.

Yet such open-mindedness, Dawkins rightly insists, is the hallmark not just of the scientific but of the rational mind more generally.  Only such prejudice explains his constant use of snide rhetoric instead of argument: do the pilgrims in Lourdes really 'wallow' in the stream rather than bathe?

Which is all a great pity.  It would be to everyone's advantage if an atheist like Professor Dawkins were to deploy his considerable talents in an honest and rational debate with equally articulate and well-informed believers.  If that were to lead to a discussion of the nature of human rationality in general, and the rationality of religion in particular, then we might be starting to get somewhere.

Dr Gerard J Hughes SJ is Master of Campion Hall, Oxford