Paul Kurtz, a now-retired professor of philosophy at the State University of New York at Buffalo, is the doyen of US scepticism. He is the founder of the Committee for the Scientific Investigation of Claims of the Paranormal (otherwise CSICOP), which over the decades has done sterling work in debunking faith healers, snake-oil salesmen, assorted telepathists, mediums, homeopaths and creationists. Prometheus Books, his publisher, is a would-be commercial off-shoot of the charitable enterprise. But his latest book is not vanity publishing: it is an invaluable collection of essays on the compatibility of science and religion.

More accurately, I should have written 'incompatibility', for most of the contributors are obdurately sceptical. And although they include heavyweights whose positions are well known, the occasion seems to have brought out the best, or most forthright, in them.

One of these is the Nobel prize winner and theoretical physicist Stephen Weinberg, who neatly demolishes the notion of the "designer Universe". In passing, he knocks down one of the Design School's favourite arguments - that the Universe is exquisitely designed for life (as we know it) because carbon is amply produced in stars only because a certain excited state of the carbon nucleus has certain precise properties, indicating that some designer has fixed the crucial parameters. Not so, says Weinberg: the argument compares oranges and apples.

There is an epigram of sorts buried towards the end of his essay. The "biological creationists used to say the Universe is so uncongenial to life that life could not have evolved naturally, now they say that it is so congenial to life that [it is] the Universe [that] could not have evolved naturally".

Another contributor is Owen Gingrich, a professor at the Harvard-Smithsonian Institute for Astrophysics and best known as a superb historian of his field. He is the only confessed believer in this symposium of essays. His title is "God's Goof and the Universe that knew we were coming". (The first half of the title was coined by George Gamow, the second by Freeman Dyson.)

Gingrich's argument is that there can be no scientific proof that God does not exist (which is surely correct) and that there is "an astonishing confluence of parameters that are tuned just right to make a world habitable by intelligent life".

This is a statement of the so-called Anthropic Principle - that the existence of life on the Earth places constraints on the properties of the Universe. The excited state of the carbon nucleus that Weinberg has shown to be irrelevant is part of that story.

Nobody would quibble with the inference that because there has been life on Earth for the past 4 billion years, the Earth must be older (the correct age is more like 4.5 billion years) and the Sun at least as ancient. But the religious take arguments of this kind much further.

'God's goof' is the failure to arrange for the existence of atomic nuclei five times more massive than the nucleus of hydrogen (the particle called a proton). If there were stable nuclei of mass five, it is indeed likely that stars would have been less prolific sources of carbon and that life (as we know it) would not have emerged. But it seems a huge leap into the dark to say that logic leaves only three choices - (a) God designed the Universe with human beings in mind; (b) ours is one of many universes; and (c) only one set of parameters is possible.

While the origin of the Universe is as uncertain as it remains, and when so little is known of the conditions required for living things of any kind to exist, why not settle for just one possibility - that the Universe is the Universe in which we live and that, as time passes, we shall understand it better?

That, sadly, does not not decide the question of whether we should believe, but merely postpones it. Kurtz's symposium cleverly juxtaposes a piece by the late Stephen J. Gould - the evolutionist and true Darwin scholar - with one from Richard Dawkins.

Gould, scholarly as ever, has chosen to compare the texts of Pope John Paul's recent (1996) averral that the essentially Darwinian theory of evolution can be considered as proven with the encyclical of Pope Pius XII (Humani generis, 1950) which said that Roman Catholics could espouse evolution provided that they insisted that the soul entered the body by a separate (and unspecified) mechanism - and which added that Darwinism was, in any case, not proven. The inference that the Church had moved forward fitted well with Gould's view that science and religion are not so much incompatible as orthogonal: we look to one for explanations, the other for moral guidance.

Dawkins is much more robust. He too has read the two popes, but notes that even John Paul's version has it that "theories of evolution…which consider the mind as emerging from the forces of matter, or as a mere epiphenomenon of this matter, are incompatible with the truth about man." In short, the whole current agenda of neuroscience is anathema to the Catholic Church.

Elsewhere, Dawkins has called Gould's contention (and that of many others) that science and religion can coexist the "agnostic conciliation". It is not meant as a term of approval. But he is surely right. Explanations requiring the supernatural are now not merely quaint but harmfully distracting to children and other innocents.