In an October 29 New York Times article on George Bush, Nicholas Kristof reports: "Characteristically, he does not believe in evolution - he says the jury is still out - but he does not actively disbelieve in it either; as a friend puts it, 'he doesn't really care about that kind of thing.'" (Also see in these pages May 9, 2004: On your knees, America!.)

It's often said that because evolution happened in the past, and we didn't see it happen, there is no direct evidence for it. That, of course, is nonsense. It's rather like a detective coming on the scene of a crime, obviously after the crime has been committed, and working out what must have happened by looking at the clues that remain. In the story of evolution, the clues are a billionfold.

There are clues from the distribution of DNA codes throughout the animal and plant kingdoms, of protein sequences, of morphological characters that have been analyzed in great detail. Everything fits with the idea that we have here a simple branching tree. The distribution of species on islands and continents throughout the world is exactly what you'd expect if evolution was a fact. The distribution of fossils in space and in time are exactly what you would expect if evolution were a fact. There are millions of facts all pointing in the same direction and no facts pointing in the wrong direction.

British scientist J.B.S. Haldane, when asked what would constitute evidence against evolution, famously said, "Fossil rabbits in the Precambrian." They've never been found. Nothing like that has ever been found. Evolution could be disproved by such facts. But all the fossils that have been found are in the right place. Of course there are plenty of gaps in the fossil record. There's nothing wrong with that. Why shouldn't there be? We're lucky to have fossils at all. But no fossils have been found in the wrong place, such as to disprove the fact of evolution. Evolution is a fact.

It comes, I'm sorry to say, from religion. And from bad religion. You won't find any opposition to the idea of evolution among sophisticated, educated theologians. It comes from an exceedingly retarded, primitive version of religion, which unfortunately is at present undergoing an epidemic in the United States. Not in Europe, not in Britain, but in the United States.

My American friends tell me that you are slipping towards a theocratic Dark Age. Which is very disagreeable for the very large number of educated, intelligent and right-thinking people in America. Unfortunately, at present, it's slightly outnumbered by the ignorant, uneducated people who voted Bush in.

But the broad direction of history is toward enlightenment, and so I think that what America is going through at the moment will prove to be a temporary reverse. I think there is great hope for the future. My advice would be, Don't despair, these things pass.

It's said that the only rational stance is agnosticism because you can neither prove nor disprove the existence of the supernatural creator. I find that a weak position. It is true that you can't disprove anything but you can put a probability value on it. There are an infinite number of things that you can't disprove: unicorns, werewolves, and teapots in orbit around Mars. But we don't pay any heed to them unless there is some positive reason to think that they do exist.

? For a long time it seemed clear to just about everybody that the beauty and elegance of the world seemed to be prima facie evidence for a divine creator. But the philosopher David Hume already realized three centuries ago that this was a bad argument. It leads to an infinite regression. You can't statistically explain improbable things like living creatures by saying that they must have been designed because you're still left to explain the designer, who must be, if anything, an even more statistically improbable and elegant thing. Design can never be an ultimate explanation for anything. It can only be a proximate explanation. A plane or a car is explained by a designer but that's because the designer himself, the engineer, is explained by natural selection.

A delusion is something that people believe in despite a total lack of evidence. Religion is scarcely distinguishable from childhood delusions like the "imaginary friend" and the bogeyman under the bed. Unfortunately, the God delusion possesses adults, and not just a minority of unfortunates in an asylum. The word "delusion" also carries negative connotations, and religion has plenty of those.

? A delusion that encourages belief where there is no evidence is asking for trouble. Disagreements between incompatible beliefs cannot be settled by reasoned argument because reasoned argument is drummed out of those trained in religion from the cradle. Instead, disagreements are settled by other means which, in extreme cases, inevitably become violent. Scientists disagree among themselves but they never fight over their disagreements. They argue about evidence or go out and seek new evidence. Much the same is true of philosophers, historians and literary critics.

But you don't do that if you just know your holy book is the God-written truth and the other guy knows that his incompatible scripture is too. People brought up to believe in faith and private revelation cannot be persuaded by evidence to change their minds. No wonder religious zealots throughout history have resorted to torture and execution, to crusades and jihads, to holy wars and purges and pogroms, to the Inquisition and the burning of witches.

That trend toward enlightenment has indeed continued in Europe and Britain. It just has not continued in the U.S., and not in the Islamic world. We're seeing a rather unholy alliance between the burgeoning theocracy in the U.S. and its allies, the theocrats in the Islamic world. They are fighting the same battle: Christian on one side, Muslim on the other. The very large numbers of people in the United States and in Europe who don't subscribe to that worldview are caught in the middle.

Actually, holy alliance would be a better phrase. Bush and bin Laden are really on the same side: the side of faith and violence against the side of reason and discussion. Both have implacable faith that they are right and the other is evil. Each believes that when he dies he is going to heaven. Each believes that if he could kill the other, his path to paradise in the next world would be even swifter. The delusional "next world" is welcome to both of them. This world would be a much better place without either of them.