Insiders' view of universe of ideas not for novices

I once attended a seminar by the physicist Francis Crick, who by then had long abandoned his work on the structure of DNA and had turned his attention to the nature of consciousness. It was enthralling to sit in the presence of a great scientist talking in full flow about the workings of the mind, but it was hardly the best way of understanding the subject. One gets similar feelings when reading Science at the Edge .

The book reveals the thoughts of some 22 of the world's leading scientists in three main areas - fundamental physics, computing and human nature. Most of the chapters are based on interviews conducted by John Brockman, the New York literary agent who recorded them for his web-based forum Edge. It is like having a front-row seat at the ultimate scientific seminar series.

Brockman calls these scientists "the new humanists". According to his introductory essay, which first appeared on Edge in April 2002, they are people at the vanguard of their disciplines who are asking the most intellectually exciting and fundamental questions about the universe and our place in it. Many are well-known popular-science writers; they include the physiologist Jared Diamond, the philosopher Daniel Dennett, computer scientist Marvin Minsky and the physicists David Deutsch, Sir Martin Rees and Lee Smolin.

Unlike "self-reverential" humanities scholars, who merely reinterpret and recycle what earlier thinkers thought, the new humanists are pushing knowledge forward and acquiring relevant and valuable information, according to Brockman. They have, apparently, led us into "one of the most dazzling periods of intellectual activity in human history". Whether this is true is debatable, and Brockman is right to include an epilogue in which opponents challenge his view.

Not all science is useful, while some research in the humanities is relevant to the real world. Science also abounds in received doctrines that - as Dennett puts it - "one questions at the risk of being branded a fool or worse". In fact, says philosopher Denis Dutton, too much of the so-called jargon that humanities scholars use is due to them foolishly trying to ape scientists.

So what do the new humanists have to say? Steven Pinker argues that the mind is not a blank slate shaped by the environment but is shaped by genetics. David Gelernter thinks that computers will become less like "glorified filing cabinets" and more like artificial minds. Ray Kurzweil thinks that technological progress will move so fast that we will eventually reach a singularity that will "rupture the fabric of human history".

Lisa Randall explains why string theory says that we might live in an 11-dimensional world. Paul Steinhardt thinks we live in a cyclic universe that is constantly expanding, cooling and expanding again. Seth Lloyd calculates how much information could be stored in the "ultimate laptop" computer with a mass of 1 kilogramme and a volume of 1 litre - and what might happen if its density was increased so much that it became a black hole.

Big ideas come and go at dizzying speed, which is fun to start with but exhausting after a while. Jargon is common. One craves a change of pace or an easy anecdote. Colleagues are often referred to without explanation - psychologist Stephen Kosslyn refers to "another round in my old debate with Zenon Pylyshyn", who is "a good friend of Jerry Fodor". I have no idea who either is. Like bad speakers at departmental seminars, too many of the chapters ramble; unlike the departmental seminar, there is no scope to ask questions.

One problem with the book is that Brockman has deliberately edited himself out of the interviews. What this means in practice is that question-and-answer conversations that are easy to follow on the Edge website become single blocks of text that often jump from topic to topic.

Many chapters lack structure, based as they are on whatever questions Brockman happened to ask at the time. Brockman himself says that these chapters do not "in any way represent (the scientists') own writing".

When the interview approach works, the book is excellent. The best chapter is by Smolin on "loop quantum gravity", which is a rival to string theory as a way of uniting relativity with quantum theory. Smolin strikes the right balance between asking the big questions and ensuring that his explanation can be properly understood by non-experts.

So if you want to get a flavour of some of the cutting-edge questions at the frontiers of science, Science at the Edge is the book to read. But if you want a careful, logical, ordered introduction to those topics, look elsewhere.

Matin Durrani is deputy editor, Physics World.