None the less, misleading caricatures are common in disputes about evolutionary biology. The more popular they are, the more misleading they become. Rose is himself a fearsomely rude controversialist. Why force a correction by mentioning legal advice in a letter of complaint to the publishers? The answer, he says, is that the offence was committed in a speech bubble. "The author had literally put into my mouth a completely fatuous statement which was not one which any biologist or any sane person would make." The original bubble says: "Whether you become a genius or an idiot depends entirely on what environment you live in", and it's hard to see how anyone with even an O-level in biology could say that. "I am happy to have a public discussion about intellectual or scientific or political issues," says Rose. "But a bubble in somebody's mouth making a completely fatuous statement is simply defamatory."

The author, Dylan Evans, a post-graduate student at the LSE, has apologised to Rose, and the publishers, like the professor, feel that the whole affair is over, or will be, as soon as all the stickers are on and the book is out. But Evans has also complained on an internet mailing list, and to various newspapers, that the affair raises questions of academic freedom. "There is something very worrying when academics resort to threats of legal action to settle intellectual disputes. Indeed, when academics become so litigious, this raises serious questions about the freedom of academic debate." Rose replies that this was not an academic dispute; it was a simple matter of factual accuracy. He also says that he had never threatened legal action, just pointed out to the publishers that he had been advised that the original speech bubble was defamatory. "The advice I would have for Dylan Evans is very simple. When you're in a hole, stop digging."

Under the contract with Icon Books, Evans has to bear all the costs for the restickering, so it has obviously proved a costly and painful mistake for him. But his attempts to recast the story as one of persecution for daring to talk about the role of genes in human development are not entirely convincing. "I spend my research life studying genes down a microscope," says Rose.

If anything, the affair shows up once more the abyss of incomprehension and mistrust which separates the two sides in the long-running feud over evolutionary psychology. Rose is perhaps the leading opponent of evolutionary psychology, and the London School of Economics (LSE), where Dylan Evans works, is its leading outpost in Britain. The Darwin seminars, run by the philosopher Helena Cronin at the LSE, have introduced an entire generation of metropolitan intellectuals to the delights of Darwinian analysis as a means to answer almost every question about human nature, from why children don't like spinach to why so few women run large US companies. She has arranged for many of the founders of evolutionary psychology to lecture there.

But they have not convinced sceptics such as Rose that these theories are more than superficially plausible and certainly not that they represent properly established scientific truth. In a recent article, angrily circulated by Evans, Rose dismisses "the gallery of shallow ideologically driven thinkers grouped around the quasi-defunct Darwin Centre". This is not especially rude by the standards of polemics in this field. The American evolutionary psychologists John Tooby and Leda Cosmides have published a blistering attack on Stephen Jay Gould on their website .

It is easy to see roughly who is on which side is these arguments. Rose's allies include the philosopher Mary Midgley and the American biologists Stephen Jay Gould and Richard Lewontin. Those on the other side include Richard Dawkins, Matt Ridley and Helena Cronin in this country; Dan Dennett, Steven Pinker and EO Wilson in the US. The long and tangled webs of personal friendships and enmities involved go back, in some cases, to the 60s, and the questions in dispute range over almost every aspect of human nature. Rose, for example, first became embroiled over claims about the genetic factor in human intelligence. It is, broadly speaking, true that the critics of evolutionary psychology are on the left politically. The angrier their criticism, the further to the left they tend to be, because they believe that bad science matters more when it is used to condone injustice. The supporters of evolutionary psychology are more widely spread politically, but share at least a folk memory of being oppressed by political correctness, after the early campaigns against them in the 70s.

To the leftwing critics of evolutionary psychology, much of it is simply "Flintstones anthropology" that justifies inequality and injustice by invoking Science, just as 19th-century Christianity justified "the rich man at his castle, the poor man at his gate" by invoking God. As an example of the areas in dispute, consider the theory of Kingsley Browne, an American lawyer, as to why there appears to be a "glass ceiling" which prevents women from rising to the top of large corporations, even after 30 years of equal-opportunity legislation.

In a recent book from the Darwin Centre at the LSE, Browne argues that there is, in fact, no glass ceiling. Inequality of out comes under present legislation is a result of men being born more competitive: women, he claims, have evolved to be less interested in risk-taking than men, essentially because, among our ancestors, women were attracted to high-status males, and males gained status by successfully taking risks. In the nature of things, this is going to produce very strong selection for males who are good at taking risks. You might think that the qualities which make a successful hunter of sabre-tooth tigers are not those which distinguish a widely feared accountant, but that is where the second half of Browne's argument comes in. Risk-taking, he says, is what unites the successful hunter and the successful CEO. Men reach the top of companies because they have evolved to care more about status than women and to risk more to get it. That's why they get paid more, and there is nothing we can do about it.

This is a fairly typical example of modern evolutionary psychology reasoning, in that it is plausible and a lot more subtle than it may seem; but also really very hard to prove, and - if you take it seriously - fraught with policy-making consequences. Rose claimed, in a recent article, that it is simply "a last-gasp attempt to recruit 'science' to hold back the rising tide of change". I think he's unfair to Browne's theory, which confines itself to asking why men get more of the very top jobs, rather than claiming that men will always find themselves in the best-paying and most interesting jobs as a consequence of biological fact. But it is clear that such reasoning could be used to obnoxious political effect and that it doesn't have the status of established scientific truth in the way that some other theories about genes and their effects do.

What makes these disputes so difficult to isolate, or to understand away from their personal and political matrix, is that everyone is a Darwinian now. All the parties in these disputes talk about genes, and offer Darwinian explanations. How did this come about? The answer is to be found in the way that when the two sides talk about "genes" they mean rather different things. The evolutionary psychologists are heirs to an intellectual revolution in the 60s and early 70s, whose excitement is clearly preserved in Richard Dawkins' first book, The Selfish Gene. They saw that you could talk confidently and with mathematical rigour about the effects of genes on behaviour, even if you didn't ask which bit of DNA was which gene exactly, nor how it worked. So, to give a controversial example, we can be confident that there are genes for human intelligence which are different from the genes which cause a chimpanzee's brain to grow as it does. It is both a strength and a weakness of this view that we can do this without having any idea of how many genes we are talking about, or any account of how they produce their effects. The mathematics and the game theory are independent of the mechanism.

But for Rose and for other biologists who actually work on the details of the mechanism, this is not enough. They don't want to know which hypothesised genes might have the effects that theory demands; they want to know which identified genes have the actual effects, and how. This is something which we do not understand even when examining C Elegans , a transparent worm with only 943 cells which, last year, became the first multicellular animal to have its genome completely mapped. We know every atom of its DNA. But we still don't understand how this encodes the instructions to turn a single fertilised egg into a complete worm; and C Elegans doesn't even have a brain. When you are dealing with the genetics of human inequality, things would be more complicated even if brains were specified only by genes. But they are not. Your brain is constantly changing physically as the result of experience, and much of this experience is the result of interaction with other brains, and the social systems we and our ancestors have made. Perhaps, far in the future, when the human genome has not just been mapped, but the map has been understood, all these disputes will fade away. But if the evolutionary psychologists are right, they won't. A tendency to argue over genes and human nature is embedded in our genes.