James Dewey Watson is a remarkable man, one of the very few people of his time whose names are certain to be known to generations not yet born.

When he was twenty-four, he and Francis Crick discovered the structure of DNA, the double helix that has become one of the great symbols of human knowledge; for this they shared the Nobel Prize with Maurice Wilkins (had she lived, Rosalind Franklin might also have been acknowledged). Watson became a professor of biology at Harvard, and is Director of the Cold Spring Harbor Laboratory, where he has encouraged some spectacular research in molecular biology. He was the founding head of the Human Genome Project, biology's Manhattan Project or Apollo Mission, the biggest biological research effort ever, in terms of money and numbers. A force to be reckoned with.

Along the way, he wrote a number of books, one of which, The Double Helix, a memoir of the discovery of DNA, became a best-seller, provoked controversy for its gossipy style – Harvard refused to publish it – and cemented his public image: brilliant, idiosyncratic, and a bit of a punk, or enfant terrible as they like to say in academic circles. As a young genius, he made something of a fetish of wearing sneakers with the laces untied; as an eminence, he achieves the same effect by publicly calling statements he disagrees with 'crap'.

What might politely be called his forthright approach certainly garnered him some enemies. E.O. Wilson once described him as having been, in the fifties and sixties, "the most unpleasant human being I had ever met" and it's not hard to understand why. Watson's contribution to one faculty discussion was, "Anyone who would hire an ecologist is out of his mind," which is scarcely calculated to win friends and influence people, especially ecologists like Wilson, to whom this was addressed. Much later, his reaction to an experiment that seemed to show dramatic improvement in the memory of fruit flies is said, perhaps apocryphally, to have been, "We're going to be rich!"

Brutal honesty of this kind is a high-risk tactic. It can be endearing, it can be funny, and it can definitely be memorable. Which is surely part of the point. Watson certainly has a competitive streak in him; Crick once said, apropos the 'race' to discover the structure of DNA, "The only person who thought it was a race was Jim, nobody else did." Watson is also undoubtedly committed to advancing the cause of science, and sincere in his desire to alleviate human suffering. Indeed, his drive is inseparable from his accomplishments.

As is his sense of self-worth, especially intellectually. He is quoted by Jonathan Weiner (in Time, Love Memory: Alfred A. Knopf, New York, 1999) extolling "the freedom to have your brain work right. As distinct from most people, whose brains don't work right." And we are left with the distinct impression that Watson does know intimately at least one exception to that generalization.

And yet. In the same book, he muses on free will: "You know, when I'm in a room, and I hear shit, after a while the word 'shit' is going to come out. You just can't take it anymore. Now that's, hmmm, a predictable response. It's bound to come out. I think to myself, maybe I'll sit through nonsense and not say it. But ... So in that sense you don't have a free will. Your reactions are programmed."

There is a word for this behavior: coprolalia, defined in the American Heritage Dictionary as "the uncontrolled, often excessive use of obscene or scatological language that may accompany certain mental disorders, such as schizophrenia or Tourette's syndrome." In its mild form, from which Watson seems to suffer, it is commonly referred to as being obnoxious. More gently – but perhaps more devastatingly – one might say that his brain doesn't work right.

Another minor detail: Crick, somewhat miffed by the portrayal of him in The Double Helix, which opens, "I have never seen Francis Crick in a modest mood," threatened to begin his own memoir, "Jim was always clumsy with his hands. One had only to see him peel an orange ..." Presumably we can therefore add to the list of Watson's imperfections some minor problems in physical coordination.

So what? No one's brain works right, not completely. Personally, I wouldn't change a thing about Jim Watson. Taken all in all, I'm glad he exists. And if he were better at peeling oranges or schmoozing with idiots, he would not be himself. If it is partly true that he is famous because he wanted to be famous, still that urge drove him to genuine achievements. And it's worth noting that the tactless comment about ecologists presumably came during an academic turf war (notoriously vicious as they are, perhaps because, as Henry Kissinger once remarked, the stakes are so low), while a large part of his job at Cold Spring Harbor is making sure that the enterprise is funded.

The point here is more complex than that everyone is flawed. More, also, than that anyone who proposes to alter the genetic makeup of the unborn would be well advised to give up the goal of perfection. Consider, as a lax kind of thought experiment, two worlds we don't live in – one in which everyone is as acerbically brilliant as Watson, and one in which nobody is. In the former, there is every chance that we would never have cooperated enough to produce a significant civilization at all; in the latter, we'd have been too damn dumb.

Poets are the unacknowledged legislators of the world, said Shelley, a poet. Philosophy is the most important of disciplines, say the philosophers. Science is the hope for the future, say the scientists. To all of whom, I say, as a poet with a degree (partly) in Philosophy and an interest in science: A world in which any of you rule is not a world I wish to see. Nor is a world where none of you thrive.

The unfortunate but all too human fact of the matter is that human greatness is intimately connected with obsession and self-centeredness. The mystic in the cave pursuing enlightenment and not-being is, let's face it, to some extent sponging off the rest of us. So is the Nobel prize-winner. Any civilized society needs both. Conversely, the janitor and the humble clerk are as essential to any substantial enterprise as the managers and skilled technicians (and ought to be paid vastly more than they typically are). We're in this world together. But we are in it as individuals, and that skews our perspective. Our ambition, drive and ideas come to us alone, but we always act in the context of others. Since, however, we experience our actions from our own unique vantage points, a distorted view is built into our picture, quite inevitably. We all see ourselves as the center of the universe.

None more than the truly distinguished. The rich generally believe they deserve their wealth, and often have strange ideas of what constitutes a modest income ("I could easily live on a couple of hundred thousand a year" – from memory, that was the actress Demi Moore; John DeLorean in the early 1980s claimed he wasn't after money because he only needed $75,000 a year, which, allowing for inflation, is much the same); while the intellectually eminent often attribute their success to 'pure' brainpower, discounting such factors as luck – whether in their parents' social status, or simply in their choice of problems to solve – or indeed a talent for self-promotion. It is no surprise to discover Watson describing a proposed law regulating human cloning as 'imbecilic'; that's the standard insult. Nor to find Professor Lee Silver writing to someone who came to disagree with him, "You used to be so smart." Modesty and self-doubt are not the characteristic traits of the very successful.

Society benefits when scientists and poets focus all their varying energies on their particular goals. Their families may suffer, they may be lousy to live with and not much fun to be around; they may be scheming for prizes and glory; they may be absurdly ignorant of the concerns of 'ordinary' people; they may in fact be lousy human beings, exactly because of the qualities that bring them success in their chosen fields. Without them, we would all be the poorer. But that is no reason to praise, let alone imitate, their flaws.

What becomes a legend least may well be what made the legend great.