The Diversity of Life
The Language Instinct
The Beak of the Finch
The Short Life and Very Hard Times of Cold Fusion
Remaking the world atom by atom
Darwin's Dangerous Idea
Shadows of the Mind
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The Diversity of Life

Edward O. Wilson
Allen Lane, £22.50, p424
The Voice of the Earth
Theodore Roszak
Bantam Press, Pound17.99, p368

FEW people would deny that human activities are now having a major impact on life on Earth. Tropical forests are being cleared today, just as temperate forests were cleared a hundred and more years ago. The face of the land is changing, and many species of both plant and animal life are disappearing as a result. The only basis for argument is whether or not this matters.

Edward Wilson, of Harvard University, and Theodore Roszak, of California State University, are both passionately convinced that it does matter, and in their new books they argue eloquently that it is time we mended our ways and took more account of the damage we are doing to the biosphere of our planet. Their approaches, though, are very different. Roszak speaks with passion, from the heart; Wilson speaks from the head, writing with clarity and precision and never getting a fact wrong. The slight surprise is that it is Wilson's approach that is the more compelling and persuasive, and makes for an enthralling read. This is only a slight surprise because Wilson has already twice won the Pulitzer Prize for his writings on matters scientific, and seems incapable of writing badly. He describes the diversity of life today and the means by which that diversity has evolved, and points to six occasions during the history of life on Earth when there have been great "extinctions", wiping out large numbers of species and setting that evolution back by millions of years. Five of those extinctions occurred between 450 million and 65 million years ago, the most recent of the five being the event that caused, among other things, the death of the dinosaurs. The sixth extinction is happening now. It is likely to be bigger than any of the other five -- and it is all our own work. When the facts speak so dramatically, it is hardly necessary to become emotional about what is going on. Roszak's approach can best be summed up from the subtitle of his book -- "an exploration of ecopsychology". This is the Californian hippy view of impending catastrophe. He takes the concept of Gaia (the notion that the entire biosphere of the Earth can be regarded as a single living organism), and suggests that what is happening now is a result of a madness afflicting Gaia. But where Wilson starts with the facts and leads the reader to inevitable conclusions about the need for better stewardship of the planet, Roszak starts from an emotional belief in the need for good stewardship, and bends the facts to fit his preconceptions. He lays blame for the Black Death of the fourteenth century, for example, solely on "a virus carried by a flea that rode on the back of a rat". He totally misses the now well-established point that the collapse of the later Middle Ages was caused first by a climate shift, bringing cool, wet weather that destroyed harvests and left populations starving and vulnerable to the infection. And although he correctly identifies a shift in the thinking of scientists today, away from the mechanistic clockwork of Newtonian mechanics, he describes the "New Physics" of Planck, Bohr, Heisenberg and others as "tearing down the remaining ramparts of materialism" at the end of the nineteenth century. Bohr was only born in 1895, and Heisenberg not until 1901; hardly surprisingly, the revolution they led actually took place in the 1920s! This inaccuracy is typical.

In view of the way he seems eager to move the quantum revolution back a generation, it is surprising that Roszak seems unaware of a new revolution taking place today. Discussing evolution, he leans towards the mystic, saying that natural selection "is exactly the way life might be installed on Earth" from outside, and claiming that "there is no form of natural selection that resulted in the presence of such life- supporting necessities as the water on the globe". In fact, there is, but it requires extending the Gaia concept outwards, to embrace whole galaxies of stars rather than individual planets -- and Roszak's understanding of matters astronomical is distinctly sketchy.

Most infuriating of all, however, is the way in which Roszak ignores the work for which Wilson won his first Pulitzer Prize. This concerns sociobiology, which offers an explanation of the way people behave in terms of the evolutionary pressures experienced by our ancestors. It is no good saying, as Roszak does, that the ills of the world are caused by the way we bring up boys and girls differently without addressing the question of why boys and girls are different.

The "root of our environmental dilemma" may well be linked to the fascination young men have for movies such as Terminator and Robocop, as he suggests; but the reasons why boys like such movies has as much to do with the success of an African ape in becoming civilised as with the lack of "a female and feminist Freud" to change the way we think. The woolly thinking, imprecision and errors that riddle this book mean that it will do as much harm as good in the fight to save the planet. Woolly thinking, imprecision, and errors are, though, completely alien to Wilson's work. He is entranced by all forms of life, including the "cookie cutter shark", which gets its name from its habit of biting circular chunks of flesh from the living bodies of porpoises and whales, and he writes lyrically of the delights of sitting in the dark in a clearing in the rainforest, fitfully lit by the lightning from an approaching storm, using a torch to spotlight the wolf spiders out on the prowl for prey.

But the heart of Wilson's book is the final section in which he explains, more clearly than I have ever seen it explained, the true value of the diversity of life. It has become a cliche to talk of the possibility of finding new drugs (like aspirin) and new foodstuffs (like potatoes) in the diminishing rainforest. Wilson explains how soundly based these possibilities are, and draws attention to the already known food plants that are at present enjoyed by Amerindians but which have outstanding worldwide potential as crops.

The bottom line of Wilson's story is almost unbelievable. About 1.4 million species of plants, animals and microorganisms have so far been identified and given scientific names. But at least ten times as many species, and possibly as many as 100 million, remain to be identified. Calling for a major effort to find out just what species we share our planet with, and referring to them as "unmined riches", Wilson points out that the effort would cost about half as much as the current project to map the human genome, and only a fraction of one per cent of the cost of a manned expedition to Mars.

He leaves the reader in no doubt that humankind has got its priorities seriously wrong, and that there may indeed be a madness afflicting Gaia. But this is not a polemical, proselytizing book. It is a calm, thoughtful appraisal of the diversity of life on Earth -- an appraisal which could all too easily become an obituary. If you only plan to read one science book this year, this is the one.

The Language Instinct

The new science of language and mind
Steven Pinker
John Gribbin

Where does language come from? How do we all know how to speak so effortlessly? One school of thought would have you believe that it is a cultural phenomenon -- that babies learn to speak by copying their parents. An opposed camp holds that it is instinctive, an ability that has been shaped by evolution in the same way that our ability to stand upright has been shaped by evolution, so that we no more have to think about how we make sentences than we have to think about each muscle movement involved in walking.

Steven Pinker speaks for the second school, and does so so effectively that he leaves you wondering how there can ever have been any doubt about the origins of the language instinct. His own use of language is a powerful advertisement for this human ability, as he lays his stall out with clarity and candour:

The workings of language are as far from our awareness as the rationale for egg-laying is from a fly's. Our thoughts come out of our mouths so effortlessly that they often embarrass us, having eluded our mental censors. When we are comprehending sentences, the stream of words is transparent; we see through to the meaning so automatically that we can forget that a movie is in a foreign language and subtitled.

Pinker is a Canadian who carries out research into language at the Massachusetts Institute of Technology. The message he has for us is a development of the ideas of Noam Chomsky, that brains are "prewired" to handle grammar; but with two important differences. First, Chomsky's own use of language is sometimes so difficult to deal with that it leaves even an enthusiast for the subject floundering; secondly, unlike Chomsky Pinker goes the whole hog in arguing that both the physical structures in the brain used in language and the communicative power of human beings have been honed directly by the Darwinian process of evolution by natural selection. In other words, the ability to communicate more effectively has been refined, step by step, by evolution -- in the same way as, say, the spider's ability to spin a web more effectively has been refined, step by step, by evolution.

Now, I am often amazed by the adverse response that can still be provoked in some quarters by the suggestion that any human attribute, and especially those attributes we regard as uniquely human, have been subject to this kind of selection. More than a hundred years after the death of Charles Darwin, there are still people who bristle at the thought of applying evolutionary ideas to people in the same way that the are applied, without any hint of controversy, to other species. As John Maynard Smith says in the introduction to the Canto edition of his book The Theory of Evolution, "until evolutionary ideas again become respectable [in the context of linguistics], the origins of language are likely to remain obscure". But both Darwin and Smith would surely be impressed by the way in which Pinker sheds light on these questions.

The Language Instinct is a superb book simply at the level of being a good read, packed with fascinating facts and information about how babies do learn to talk, how languages differ from one another and in which ways they are similar, and what the structure of pidgin languages and creoles (the languages that result when children make a pidgin their native tongue) tell us about how the brain works. Pinker debunks bunk with panache, cuts through the confusion of jargon, and tells a mean anecdote. He does for language what David Attenborough does for animals, explaining difficult scientific concepts so easily that they are indeed absorbed as a transparent stream of words. And he provides the most devastating demolishment of the nit-picking pundits who object to perceived grammatical infelicities that it is ever likely to be my pleasure to peruse.

Leading in to a vastly entertaining chapter about slang and similar "wrong" uses of language, Pinker likens criticism of these methods of communication to an expert on song who points out "errors" in the song of the humpback whale. "Isn't the song of the humpback whale," asks Pinker, "whatever the humpback whale decides to sing?" In the same way, the language of the black ghettos of Chicago is whatever the people who use that language decide to speak, and anyone who tries to make rules about how people "ought" to talk, and impose those rules on others, is doomed to failure. As Pinker makes clear, there is a world of difference between finding out from scientific study what the innate rules of grammar are, and deciding arbitrarily what the rules ought to be on the basis of logic and, indeed, culture.

Using examples and explanation with effectiveness and weight, Pinker makes an unanswerable case that people use language properly as a means of communication, even when those usages break the putative rules of grammar, such as "don't split infinities", laid down by the self-appointed authorities he refers to as "language mavens", from the Yiddish word for expert. This whole section is a sheer delight to any user of language who has ever been taken to task for writing down what sounds good instead of what is allegedly "correct"; it will bring joy to Star Trek fans; and it establishes more clearly than anywhere else that English is indeed a living language.

The Language Instinct is the kind of book that doesn't come along very often -- the most recent equivalents would be the writings of Richard Dawkins and Richard Feynman, or, going back a bit further, Darwin's own books about evolution. We are scarcely into the second quarter of 1994 yet, but I will be astonished if a better science book of any kind, let alone one accessible to the general reader, comes along this year. Surely, in just about a year from now Pinker will be picking up the next science book prize. His book is groundbreaking, exhilarating, fun, and almost certainly right. Do yourself a favour and read it.

The Beak of the Finch:

Evolution in real time
Jonathan Weiner
Jonathan Cape, Pound18.99, p332
John Gribbin

There are still people around who think that evolution is "just a theory", in the same sense that your uncle Arthur might have some crackpot idea about how to grow better roses. "Where's the proof?", they ask. Proof there is, in plenty, but until now it has largely been buried away in technical journals and books, not readily accessible to doubting Thomases. But now here is a book that, as its subtitle suggests, describes evolution going on, in exactly the way that Darwin surmised, literally before the eyes of biologists. Deliciously, the species that can be seen evolving as they adapt to changing environmental conditions are the finches of the Galapagos islands, first made famous by Darwin himself.

The story of the twenty-year research programme that revealed evolution at work is told in a highly American, almost novelistic style by Jonathan Weiner. Just occasionally, he lurches too far towards creating a new genre, the science 'n' shopping format, as we are told, for example, that one of the scientists involved in the project, Rosemary Grant, "wears an Icelandic sweater, a long blue Laura Ashley dress, and sandals. Sunlight slants in the bay window behind her, through the spreading green arms of a katsura tree with shaggy bark." But mostly he manages to control himself, producing a book that reads as easily as a goodish novel while slipping information across adroitly. The information is so spectacular that it hardly needs dressing up with long blue dresses and sandals. Rosemary Grant, her husband Peter, and their colleagues have returned season after season to the Galapagos islands since 1970, and literally know every one of the finches on one of the islands by sight. They have kept family trees of the birds going back all that time, and know which birds have bred successfully and which have not. And they have trapped all but one or two of the birds, measuring and photographing them before releasing them back into the wild. They have watched populations decline in times of drought and boom in times of plenty; and they have seen how a change in the length of beak of a bird of less than a millimetre can make all the difference between it thriving and leaving many descendants or dying before it has a chance to reproduce. Only the biggest birds with the biggest beaks, able to cope with the toughest seeds, made it through the worst droughts.

Mixed with the page-turning descriptions of this field work under the harsh conditions on the island there is a wealth of information about Darwin himself and his theory of evolution, and the story is brought bang up to date, in technological terms, with the work of Peter Boag, who has studied the DNA in samples of blood from the finches, and can actually see the differences in the genetic code which specify the different designs of beak and make one finch good at eating seeds while another specialises in sipping nectar from cactus flowers. All of this would be well worth the price of admission on its own, but Weiner has yet more drama up his sleeve. In the final chapters he discusses the continuing resistance to Darwinian ideas, and the extent to which even among scientists non-biologists sometimes fail to comprehend how evolution works. Chemists who invented new pesticides were astonished when populations of insects developed resistance to them, but as Weiner spells out the whole point about evolution is that any new method of killing things will, unless it completely wipes out a species, give rise to a population resistant to the killer. One result is that cotton farmers in the very States of the US where resistance to Darwinian ideas is at its strongest are struggling every season with the consequences of evolution at work in their own fields.

In hospitals, bacteria that cause diseases are increasingly resistent to drugs such as penicillin, for the same reason. The drugs kill all the susceptible bacteria, but, by definition, the survivors of an attack are the ones who are not susceptible to the drug. The more you kill susceptible bacteria, the more opportunities you give the others to spread -- and bacteria breed far more quickly than human beings. The surprise, to an evolutionary biologist, is not that after half a century of use penicillin is losing its effectiveness, but rather that it retains any effectiveness at all.

But why are some people so hostile to the idea of evolution? Perhaps it isn't the idea they are hostile to at all. In one of the most telling passages of his book, Weiner describes how one of the scientists involved in the research told of a long plane flight during which he got chatting to his neighbour, and described in detail what his work was all about.

"The whole time on that plane, my fellow passenger was getting more and more excited. 'What a neat idea! What a neat idea!' Finally, as the plane was landing, I told him that the idea is called evolution. He turned purple."

Just maybe, some of the people who turn purple at the mention of the word "evolution" will read this book, and find out what a neat idea it really is, and how it explains what is going on in the world around us, not just among the finches of the Galapagos islands but in fields sprayed with insecticides and hospital wards where doctors find diminishing returns from the latest wonder drug. The Beak of the Finch is not the best place to learn about evolution if you have an open mind - - Richard Dawkins' books still fit that brief. But it is the ideal book to recommend to any doubter who asks "where's the evidence for evolution", and it is an entertaining insight into one of the most important pieces of biological research of the past twenty years. Those who already think they know a thing or two about evolution will read it with pleasure, coming away with a feeling that yes, of course, this is the way the world works.

Bad Science:

The Short Life and Very Hard Times of Cold Fusion
By Gary Taubes
512 pp
New York: Random House. $25.00


REMEMBER cold fusion? This was the "discovery", circa 1989, of a way to generate clean heat from nuclear reactions operating at room temperature and producing no radiation, using seawater as fuel. Such claims are commonplace among the crackpot fringe of inventors; the difference was that this claim came from two well-established scientists, Stanley Pons and Martin Fleischmann, backed by the full weight of the University of Utah. So it was taken seriously -- for a time. It was only when other scientists failed to reproduce the Utah team's claimed results, and the Utah team themselves failed to publish any satisfactory scientific evidence to back up their claims, that it became clear that the researchers had been deluding themselves, and that cold fusion itself had to be consigned to the crackpot fringe of science.

The underlying reasons for the premature announcement by the University of Utah on 23 March 1989 involved the traditional lust to be first that drives many successful scientists, the lure of Nobel Prizes, and the prospect of vast wealth from patent royalties. These are not, in fact, particularly rare lusts among scientists, who seldom fit the old image of dedicated professionals working for the good of humankind, with no thought for personal rewards. Scientists, as Gary Taubes' new book makes clear, are human beings like you and me, driven by the same urges that drive all of us. The story of cold fusion has already been told from a scientist's point of view by Frank Close, in his book Too Hot to Handle. But Taubes writes as an outsider, a journalist (his reports have appeared in The New York Times and Science, among others) looking in on the weird and wacky world of science, providing a much more racy narrative, while sticking scrupulously to the facts. Taubes' obsession with the facts amounts almost to overkill. He tells us that he interviewed more than 260 people in preparing the book, and admits that his editors at Random House insisted on cutting back the original version by a third. We are still left with a blow by blow -- almost day by day -- account of the cold fusion saga. It might have benefited from even more pruning, but certainly not of the many delicious footnotes which cast intriguing sidelights on the story, and sometimes provoke serious attacks of laughter.

The conviction of Pons and Fleischmann that they had achieved fusion (combining hydrogen nuclei together to make helium, essentially the process that powers the Sun) in a test tube persisted in the face of strong evidence to the contrary. Fusion on the scale they claimed ought, for example, to produce lethal floods of radiation. But as more than one critic of their claims noted, "they weren't dead".

Fusion is, in fact, almost unbelievably difficult to achieve. Even inside the Sun, where hydrogen nuclei collide at conditions of extreme heat and pressure, just one collision in every ten billion trillion (1 in 1022) results in fusion. And such nuclear reactions must generate radiation, unless the laws of physics as we know them are wrong -- in which case, we don't understand how the Sun and stars shine, or how conventional nuclear reactors (and bombs) work. So how could anybody ever have thought that they had achieved large scale fusion in a test tube? Because, Taubes makes clear, they were only fallible human beings. This is a story about people (real people, who come to life off the pages), faith (of more than one kind), and the way science is really done. The science is all here, and is reasonably accurately presented, but it is secondary to the real story. Cold fusion may be an extreme example, but every scientist will be aware of uncomfortably close experiences in his or her own area of expertise.

Some of the best passages in the book concern the frantic attempts by scientists around the world to replicate the Utah experiments once the news broke. The experiment was so simple that a freshman chemist could do it, and many tried. We also get a glimpse inside the electronic world of science, the email network that spreads news so quickly that a new theory can be disseminated in the morning, tested on the other side of the world in the afternoon, and proved wrong in the evening.

Once cold fusion was tested, it fell apart. Pons and Fleischmann themselves could have tested it, to destruction, using the simplest and most fundamental scientific technique, the "control" experiment. But they never did. Why? For the full story, you'll have to read Bad Science, which is one of the best journalistic science books around. But the late Richard Feynman could have summed it up in a nutshell. As he once said, "the first principle is that you must not fool yourself, and you're the easiest person to fool".


Remaking the world atom by atom
Ed Regis
Bantam Press
Pound16.99 pp307

John Gribbin

In the science fiction movie Fantastic Voyage, a submarine, complete with a highly plausible crew of experts including Raquel Welch, is miniaturised and injected into the bloodstream of an important scientist in order to remove a blood clot from his brain by blasting it with a miniaturised laser beam. As is so often the case, though, science fiction has proved far too conservative, and far less imaginative than what some scientists see as scientific fact. If you believe Ed Regis, the next scientific revolution is not just around the corner, but already upon us. And it doesn't involve anything so gross as shrinking macroscopic objects down to microscopic size. Instead, nanotechnology envisages building up tiny machines literally atom by atom -- and, among other things, injecting them into your bloodstream, not just to remove dangerous clots in the brain but to do routine housekeeping work, keeping the arteries defurred. One great advantage such nanomachines have over miniaturised submarines for this work is that there is no risk of them suddenly expanding again, with messy consequences for the patient. This is must the beginning of the story. NANO! is about how to "manufacture anything that was physically possible, automatically, at nearly zero cost, thereby eradicating poverty, while at the same time curing all known illnesses, making people physically younger, enabling them to live for hundreds, perhaps even thousands of years, and, as an extra, added attraction, flying them off to the planets, to the stars . . . "

Well, that's certainly a more impressive claim than those made by the average popular science book. Robot machines made of a few dozen atoms arranged to make cogs, ratchets, gears and bearings, able to carry out engineering on the smallest possible scale, could not only work in your blood stream, clearing out the arteries; they could work in the kitchen, converting grass and garden rubbish into prime beef; or they could build cars, atom by atom, out of lumps of rock. Meanwhile, computers the size of a human cell could be made as powerful as the best of today's desk-top computers, while a desk-top machine would have more power than all of today's computers put together.

Anyone who has read Ed Regis's earlier books, Who Got Einstein's Office? and Great Mambo Chicken and the Transhuman Condition will know that he is just the man to describe these extraordinary extrapolations from present technology to the future. He tells the tale in a semi-biographical style, describing the life and work of Eric Drexler, the chief guru of nanotechnology. Drexler started out as a nerdy space buff, working at MIT and hoping to build colonies in space; his interest in nanotechnology started out through a desire to find a cheap way to colonise space, and rapidly turned into a way to revolutionise every aspect of life on Earth. His most astonishing claim is that major applications along these lines should be possible by the year 2010.

Regis tells the tale in a suitably gee-whizz style, with a little disingenuity in places -- as when he expresses surprise that "a major New York house would publish a book [Engines of Creation, by Drexler] calling for the replacement of industrial civilization by a manufacturing system based on countless billions of invisible molecular robots, a book proclaiming the virtues of suspended animation". Regis, of all people, should know that any publisher would jump at the chance to publish such a book! The real surprise is that it took Drexler four years to write it.

The great thing about Regis's own book, though, is that it gives you a feel for what science at the cutting edge is like. How a wacky idea gets discussed and polished until it doesn't seem so wacky after all, and breaks out into the scientific community and the world at large. Even Drexler cannot yet make his nanomachines, but the existence of viruses (which are not in themselves alive, but are essentially robot machines that replicate themselves using the facilities of a living cell) shows what is possible.

Indeed, one of the main concerns of Drexler and his colleagues is that nanomachines might escape, spreading just like viruses to become a plague and destroy the Earth. There are echoes, once again , of science fiction -- notably Greg Bear's novel Blood Music. And there are more echoes of Sf in the earnest debate the idea of nanotechnology has generated among people concerned at how a planet full of people who never have to work and all have every material thing they want, will get along. All themes that have been addressed in detail in fiction over the past 50 years.

Will it really happen in the lifetimes of many people alive today? I'd take it all with a pinch of salt. But maybe we should all read up on the classics of Sf, in order to minimise the future shock if it does happen. And certainly everyone should read this book to see how close nanotechnology is to becoming reality. After all, it has already proved possible to write a page from a book (the first page of A Tale of Two Cities ) on a scale where each letter is made up of half a dozen atoms. On that scale, the entire Encyclopedia Britannica could be written on the head of a pin. Nano-engineers are already manipulating individual atoms and taking the first crude steps into nanotechnology; the only question is how quickly the work will progress, and how far. Personally, I think I'm ready for it. My lifetime enthusiasm for Sf means that I am well prepared to live forever, supplied with every material want, while cruising the Universe in my spaceship grown from pure diamond.

Darwin's Dangerous Idea

Daniel C. Dennett
Allen Lane p586 HB Pound25.00
ISBN 0 713 99090 2

John Gribbin

Darwin's dangerous idea is not evolution, but natural selection. Evolution is a fact, like the fact that apples fall downward from trees. Natural selection is a theory put forward to explain that fact, just as gravity is a theory put forward to explain why apples (and other things) fall. The dangerous thing about natural selection, in the eyes of many people, is that it requires nothing except the blind workings of chance to produce the variety of life on Earth today, including ourselves, from a single common ancestor in the primeval ooze of three and a half billion years ago. Before Darwin, evolution was a respectable idea, but carried with it the implication that some guiding hand was at work ensuring "progress" from the slime to ourselves; ever since Darwin, there has been no need to invoke the guiding hand.

People who have difficulty accepting this -- and Dennett lists "not just lay people and religious thinkers, but secular philosophers, psychologists, physicists and even biologists" among those "who would prefer, it seems, that Darwin were wrong" -- have fought many rearguard actions over the decades. It has been argued, for example, that at least some human attributes are special, and cannot have resulted from evolution by natural selection. Two examples of this kind of argument are human language, and consciousness. But the arguments do not stand up to close inspection, which is what they get in Daniel Dennett's superb new book.

It has been a good year for books countering the anti-Darwinian arguments. First, Richard Dawkins made the best-seller lists with his short, accessible and easy to read rebuff, River Out of Eden. Now, Dennett has produced a magnum opus which eruditely sets out to explain what evolution by natural selection is all about, to examine the myths and misconceptions surrounding it, and to lay those misconceptions to rest. Dennett knows his stuff, and he knows how to argue a case. As Director of the Center for Cognitive Studies at Tufts University, he teaches, among other things, an undergraduate course on Darwin and philosophy. He also knows how to write, in the best traditions of academics opening a window on their world for the layman, and has previously produced the acclaimed Consciousness Explained. He doesn't just tell you what is wrong with the arguments used against Darwin's dangerous idea, but uncovers the way in which the proponents of those arguments have been misled, or have misled themselves. This makes for a book which needs a lot more close attention than Dawkins' book, but which amply repays that close attention. Darwin's Dangerous Idea is, indeed, an ideal book for anyone who enjoyed River Out of Eden and now wants more meat.

Kicking off with an elegant discussion of Darwin and his antecedents, including the unsung Patrick Matthew who published a version of the idea of natural selection as early as 1831, and a clear as crystal explanation of the workings of chance, Dennett looks back at the origins of life and early evolution before getting fully into his stride with a devastating destruction of the anti-Darwinian case. He out-Penroses Roger Penrose (author of The Emperor's New Mind) with his discussion of the reasons why machine consciousness is not an impossible dream, and homes in on the way in which the writings of Stephen Jay Gould, himself a convinced Darwinian, have been misused by the anti-Darwin lobby.

Gould's "attacks" on orthodox Darwinism amount to no more than what Dennett calls a "mild corrective", but in the outside world (beyond the walls of academe, and sometimes within) they have been seen through a distorting lens and projected as an example of "evolution in crisis" with the evolutionists in disarray, squabbling amongst themselves. "That is a myth," says Dennett, "but a very influential myth," so influential that he has done a major service to science simply in setting this particular record straight. From now on, the answer to any claim that evolution cannot work "because Stephen Jay Gould has shown it cannot work" is simple -- read Dennett.

The architecture of King's College Chapel and the behaviour of the Old Faithful geyser are among the examples enlisted to support Dennett's case, as he shows how Darwin's dangerous idea, in all its original glory, actually emerges stronger from its encounter with the would-be modifiers of the theory, having proved able to explain every "impossible" example that have come up with. And Dennett is deliciously up to date with his account of some of the latest ideas from cosmology, where researchers such as the American Lee Smolin have come up with the notion that the Universe itself may have evolved -- literally, in the Darwinian sense -- through a process of variation and natural selection operating among whole families of universes that are "born" out of black holes. Concerning the ultimate mystery of the origin of the Universe itself, if anyone "were to make the tactical mistake of asking the rhetorical question 'What else but God could possibly explain it?' Smolin would have a nicely deflating reply," comments Dennett.

Which leaves as relatively small beer the task of explaining the supposedly "special" human characteristics of language and consciousness, ethics and the origins of morality, which Dennett does with panache before offering a glimpse into the future. This is the best single-author overview of all of the implications of evolution by natural selection available, and as such the volume deserves a place on the bookshelves of every thinking person. Lucid and entertaining, as well as being thought-provoking, it leaves the reader feeling just that bit cleverer when they finish it than they felt when they started, able to rub intellectual shoulders with the best. The jacket blurb for the book describes it as a "beautifully written tour de force". For once, the blurb is no exaggeration.

Shadows of the Mind

Roger Penrose
Oxford UP pp456 £??

John Gribbin

Professor Roger Penrose is a very clever man. Too clever by half, some might say; almost exactly half, as far as his new book is concerned. The first part of Shadows of the Mind is devoted to Penrose's contention that no computer can ever become a genuine Artificial Intelligence, with full consciousness. It pulls no punches, and is very heavy going indeed. Yet all it does is to set up a straw man to be knocked down. The argument is, in fact, that nothing based on the mathematical rules of computation can ever achieve consciousness. But throughout, the reader is given no reason why an artificial device could not be constructed that does whatever it is that the human brain does, and does achieve consciousness. At the very end of the book, Penrose casually mentions that he agrees that this may be possible! So all that the first 209 pages are saying is that the current approach to machine intelligence may be wrong.

The really interesting stuff here is the discussion of what consciousness really is, how it may be related to the phenomena of quantum physics, and which bits of the brain are wired up in the right way to do the trick. These are still deep waters, and the second half of the book is still very heavy going - - pitched at about the right level for someone with a degree in physics who wants to go on to research -- but at least it is rewarding. When Penrose discusses things like the general theory of relativity, quantum physics and the nature of time, you don't so much get an overview of the subject (as you might, say, from Paul Davies) as a view over his shoulder at how one of the active contributors to the debate thinks.

Like many people, Penrose thinks that there is something wrong with the standard interpretation of quantum theory, which allows for oddities such as the famous paradox of Schrödinger's cat, which can be both dead and alive at the same time. His pet resolution of these puzzles is to invoke a role for gravity in, among other things, forcing real cats to decide whether they are dead or alive. Intriguing stuff, of great interest to the specialists and quantum cat watchers, but presented in a highly selective way, with little or no discussion of rival ideas.

As you might expect from someone who made his name by developing theories of black holes (inside which time can seem to run backwards), Penrose is intrigued by the nature of time and its relationship to consciousness. This makes it all the odder that he doesn't discuss the work of people like John Cramer, in the United States, or Huw Price, in Australia, who have looked at the links between quantum physics and our perception of the flow of time. But this doesn't really matter, because by the time such issues raise their heads Penrose is at last getting into his stride, building up the pace and flow of the book to a finale which is bound to be misquoted, will please every aging hippy non-scientist who wants to believe that quantum theory is a really neat explanation of everything from UFOs to out of the body experiences (I believe their buzzword is "holistic"), and may make the book a best seller in spite of its deep technical level.

Penrose's main message, which a lesser author, eager for quick sales, might have trumpeted in the first chapter, not at the end, is that consciousness has to do with the nature of parts of the brain called microtubules, which may behave in accordance with the rules of quantum theory (usually thought to apply only on the scale of atoms and smaller entities) even though they can be several millimetres long. It makes for fascinating reading, whether or not you are convinced. It also raises an intriguing puzzle, which fans of holism will surely latch on to. Since these microtubules are present in much simpler organisms than human brains, including single-celled creatures and, indeed, the individual cells of a human body, does that mean that an amoeba, or the individual cells of your liver, are in some sense conscious?

It's all a very far cry from the sterile debate of the first half of Shadows of the Mind, and I wish that Penrose had thrown out the tedious hair splitting about the nature of computation and focussed straight in on this material, which offers the real reason for buying the book. But it really is heavy going, and although it does (eventually) say exciting things I could not recommend it to anyone who doesn't have at least a degree in physics. To give you a flavour of Penrose's approach, in an introductory section headed "Notes to the reader" (itself a turn off), after making elaborate apologies for using the masculine personal pronoun, he mentions that he will sometimes refer to his earlier opus The Emperor's New Mind. He warns the gentle reader that the page numbers he quotes come from a particular edition of that work, and then explains that if you have the other common edition the equivalent numbering is "closely approximated by the formula 22/7n, where n is the hardback page-number given here".

This advice seems to be offered in all seriousness (jokes are very hard to find anywhere in the book) and accurately indicates the kind of thinking you need in order to follow his discussion. He expects you to have a copy of his earlier book to hand for reference, and to be multiplying the page numbers he quotes by 22/7 (why not make it P?) as you go along. He is, after all, the Professor, and you are the pupil. Penrose pulls no punches, and takes no prisoners.

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