Steven Weinberg has his own ideas about the origins of the universe and, as he tells Andrew Robinson, they have nothing to do with God

Among scientists, the particle physicist and cosmologist Steven Weinberg is nearly as much of an intellectual icon as Stephen Hawking, even if he has a much lower public profile. To the science-reading public, especially at home in the United States, he is also celebrated as the author of two books: The First Three Minutes, a classic account of the origin of the universe and, more recently, a book on the "search for the fundamental laws of nature" with the slightly provocative title, Dreams of a Final Theory.

Many people, particularly Christians, have run up against Weinberg's remark in the earlier book, that "the more the universe seems comprehensible, the more it also seems pointless". Arguments between scientists and theologians about the existence or otherwise of God and how the universe was created have become commonplace, but in Weinberg's case the battlelines seem particularly clear-cut. "As time has passed", he notes, "my feelings have gotten stronger and stronger. I really dislike religion intensely."

The accessibility of Dreams of a Final Theory was no accident. It was deliberately written in a "preaching style", Weinberg tells me in his office at the University of Texas at Austin, where he is professor of physics and astronomy. He wanted to make a case for why the American people should carry on funding the Super Collider, a giant particle accelerator designed to investigate the super-high-energy physics inside atoms in the first moments after the Big Bang created the world.

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During 1993, bits of the book were quoted in the US Congress, and Weinberg, who shies away from personal publicity, found himself testifying at Senate hearings and speaking on television talk shows in defence of the threatened Super Collider, which was then under construction in Texas. But the campaign was to no avail: late in 1993, $2 billion and 10,000 man-years were written off in an effort to reduce the federal budget. The Super Collider was never finished.

"In a way the vote that cancelled it was democracy in action," admits Weinberg ruefully. "The public has always been interested in things that are directly important to them - medical cures, national defence - and they have a certain general interest in cosmology. Our big failure was that we did not succeed in making the public feel excited about learning the laws of nature. They felt excited about putting a man on the moon."

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Weinberg, however, is excited by the laws of nature. His entire professional life has been dedicated to understanding and ultimately attempting to unify the four fundamental forces that operate between and within atoms and their nuclei and hence determine chemical reactions and, presumably, the origin of the universe - the Big Bang. He won his Nobel prize for identifying the fourth of these forces, the so-called weak interaction (see box).

A greater prize, however, is still up for grabs - the understanding of what happened in the early moments of the universe, when gravitation, one of the four forces, was unified with the other three. According to the theory of the Big Bang this unification happened under conditions of unimaginably high temperature and energy, that make those inside the atom bomb pale into insignificance. To go from understanding atomic energy to explaining the Big Bang, Weinberg says, "we now have a larger energy gap to leap over than physics had in going from Democritus to the discovery of atoms at the beginning of the 20th century: and it may take us that long, 2,500 years - but I don't think so."

The hope remains string theory. String theory replaces the idea of the elementary particle as a point with the idea of it as a line or loop, a "string". The states of a particle may be produced by standing waves along this string, much like the overtones produced by a vibrating violin string. But cosmic strings keep vibrating forever, since they are not composed of atoms or anything else, only space itself.

String theory is formidably difficult -involving ten or more dimensions (as opposed to Einstein's four) - and progress has been disappointing. "There's now a theory which is supposed to be deeper than string theory which manifests itself as string theory on various approximations, called M (for matrix) theory," says Weinberg. "It's very fragmentary. There isn't a set of principles. We have a set of approximations to a theory without having the theory." But, he maintains hopefully, "great science is done that way. It's very rare you have something like general relativity, where some great genius, like Einstein, formulates a fundamental principle, then works out the mathematical consequences and publishes them in a series of articles."

It irritates Weinberg to be reminded of a historian of science who recently called string theory "the best-ever form of Platonic mysticism". "That's crap," he says forcefully. "The string theorists are trying to develop precise mathematical theories whose predictions agree with experiment. There's nothing mystical about it at all, if mystical means transcending the ordinary processes of reason. It's real cutting-edge stuff. I wish I was working in it."

For Weinberg has had his flashpoints, not only with the God squad, but also with sociologists and philosophers of science. He has been particularly scornful of speculations about science as just one more form of knowledge, no more or less "true" than other ways of understanding nature. Science, say some theorists, is a belief system and the truth or falsity of scientific statements is determined by the culture in which the scientists making those statements work. Philosopher Paul Feyerabend even went so far as to call science a "superstition".

Although Weinberg studied philosophy devotedly in his early college years and is widely read in the classics, (even today, he finds he can "get down" Aristotle, by listening to readings from him on tape while driving), he devotes a whole chapter of Dreams of a Final Theory to an attack on philosophy in science. In the book he writes: "I know of no one who has participated actively in the advance of physics in the postwar period whose research has been significantly helped by the work of philosophers."

Nor does he accept that there are strong links between cultures and the physics they practise. He is dubious that the disorder of German society after the first world war had much influence on the development of quantum mechanics by Heisenberg and others, as suggested by historian of science Paul Forman. "To me the logical progression into quantum mechanics is so compelling. I mean quantum mechanics was there to be discovered and it was sucking people into it; I tend to see these scientific theories as pre-existing whirlpools which draw us in."

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Hardly surprisingly, he was delighted by the now-famous hoax article published in the journal Social Text by the physicist Alan Sokal in 1996. Sokal's article was a parody of relativist philosophy. It cobbled together quotes from influential French thinkers such as Jacques Derrida and concluded that quantum gravity could be used to support a left-wing political line. Although the article was nothing more than pretentious nonsense, the journal's editors accepted and published it in full.

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Weinberg wrote an analysis of the issues Sokal's article raised in The New York Review of Books and then responded to the letters that followed, concluding with the remark that he had wrestled with what Derrida might have meant by "the Einsteinian constant" only to decide that "Derrida in context is even worse than Derrida out of context."

One mathematician colleague, whose education was in the continental tradition that mixes philosophy with science, felt that he had not been fair to Derrida, he says; otherwise, there was a very positive reaction, especially from working scientists. But does he think he persuaded any of the postmodernists and admirers of Derrida? "No, I don't think so. I long ago gave up the idea that I was going to persuade anyone. It seems to be part of a whole way of life, you know. 'Every boy and every gal,/That's born into the world alive,/Is either a little Liberal,/Or else a little Conservative'," Weinberg quotes from Gilbert and Sullivan. "There are people who are outside the argument, however, who look in; they may be persuaded on one side or the other."

WEINBERG ON WOMEN SCIENTISTS

Physics has always been a largely male preserve. Weinberg says this is now changing. "You see more and more women who are able to operate at the most abstract level. There are several women whose grasp of the mathematics of string theory I find awesome; I couldn't possibly match it."

This is what impresses him, not the arguments of certain feminists. "I think they have completely the wrong end of the stick. They see the opening of the hard sciences to women as something that's going to change the sciences. If that were true, it would provide a rational basis for keeping women out." He compares the situation in science today with that for Jews. "All the great men of science before 1800 were not Jewish. But no one would ask the question today, why have so few Jews contributed to science? Maybe 100 years from now no one will think of asking that question about women." WEINBERG'S PRIZE WINNING DISCOVERY

Four forces operate between and within atoms and nuclei. The gravitational interaction is probably the most familiar. The electromagnetic interaction unifies electric and magnetic fields, while the strong interaction, which holds together the atomic nucleus, is explained in terms of quarks and other subatomic particles.

This leaves the weak interaction, so called because it does not hold anything together but is instead responsible for the changes of nuclear particles.

Weinberg's breakthrough in 1967 focused on this weak interaction. His theory predicted the existence of a "weak neutral current" in the nucleus.

In 1973-74, weak neutral currents were actually detected at two particle accelerators in Europe and the US; the Weinberg theory became generally accepted; and in 1979 Weinberg shared the Nobel prize. The combined theory of all four forces is nowknown as "thestandard model" of matter.

Weinberg on modern French philosophers: 'Derrida in context is even worse than Derrida out of context'

Weinberg on women: 'Feminists think the opening of the hard sciences to women will change the sciences. If that were true, it would provide a rational basis for keeping women out'

Weinberg on the big question: 'The more the universe seems comprehensible, the more it also seems pointless'

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