He is a naturalist. He observes nature in the desert and the rainforest rather than in the laboratory. For years this meant he was an outcast from the biological mainstream. Since the deciphering of the structure of the DNA molecule in 1953, the science has been dominated by molecular biologists. These are scientists who work with strands of DNA or chains of amino acids rather than with whole living systems. Wilson, however, believes that biology must begin with the complete system of plant, animal and environment.
The enmity between molecularists and naturalists was bitter. In his recent autobiography, Naturalist, Wilson describes James Watson, the co-discover of the DNA molecule, as "the most unpleasant human being I had ever met ... the Caligula of biology". Watson, in turn, dismissed naturalists as "stamp collectors". It is a row that, Wilson tells me, has been resolved - partly because the protagonists have realised that they are two sides of the same intellectual coin.
Wilson's determination to raise the scientific standing of the naturalist led to his most controversial idea - sociobiology. From his studies of ants, he became interested in the whole living environment, its diversity and complexity. He became the first great ecologist.
His most celebrated ecological experiment was to kill everything on an uninhabited island in the Florida Keys. He then observed the phenomenal rate at which plants and animals recolonised.
He wanted to prove that naturalists were not stamp collectors, but analysts and theorists as rigorous as any other scientists. The climax of this project came with two books: Sociobiology: The New Synthesis in 1975 and On Human Nature in 1978.
Sociobiology turned out to be academic dynamite. Wilson traced animal behaviour back to its genetic origins, but then, in his final chapter, he turned his attention to humans, insisting that they too behaved according to genetic imperatives. He was at Harvard and it was the mid-Seventies, the era when it was still in some circles almost de rigueur to be a Marxist. Wilson's thesis was seen as at best a defence of the bourgeois status quo, or at worst a racist, fascist, sexist apologia. The Harvard Marxists believed all human behaviour could be socially explained and they fell on this heresy with inquisitorial fury.
This was the beginning of militant political correctness. Wilson was abused, suppressed and, at one conference, had a jug of water poured over his head. A committee was formed to destroy sociobiology, headed by the Marxist population geneticist Richard Lewontin and the biologist Stephen Jay Gould.
Undeterred, Wilson took the argument further with On Human Nature. This is a beautiful, though frequently chilling book. Its first aim is to show the overwhelming importance of our genes in determining our behaviour. From this Wilson moves on to his conviction that "cultures can be rationally designed". The investigation of our genetic inheritance and how it affected our behaviour would lead to a new understanding of human nature that would help us to design a better world.
The hard rationalism is the least attractive and convincing feature of the book. And Wilson does admit that the possibility of a designed culture does now seem far more undesirable. "The free market", he says, "is a system that we can now say has been experimentally verified, though it needs containment, especially in environmental areas." The success of the free market has shown that any attempt at rational design - based on politics of genetics - may be harmful.
But the book endures for two reasons. First because of the intensity of its biological faith. He dramatises, far more convincingly than the geneticists with their DNA molecule, the fact that humanity is at one with the living world and only by coming to terms with this fact can we hope to understand our true nature. Second, the book's real project was imaginative rather than political, literary rather than purely scientific. For it is not really about brave new genetic worlds, but about human destiny. "We have", he wrote in the opening chapter, "no particular place to go." The remainder of the book is a search for the true home of mankind. This was science as spiritual journey rather than merely hard, unconsoling facts.
The miracle of our existence after 3.5 billion years of blind replication and aimless striving is the key to our home. Wilson, however, is too much of an artist to think that merely presenting this evolutionary truth is enough, and he is too much of a humanist to shrug his shoulders and say, as many do: that's the way it is, there is no more to be said and no consolation to be found.
So in his conclusion he writes: "the evolutionary epic is probably the best myth we will ever have". He offers our biological destiny as the one sure basis of human nature. For him, this answer has all the mythic, artistic and cultural power of a religion. We are on the brink of discovering "the deepest needs of human nature" and we must be "kept strong by the blind hopes that the journey on which we are now embarked will be farther and better than the one just completed".
In a subsequent book he extended his thesis into the specific details of human culture. Then he returned to his ants, producing colossal, standard works of myrmecology in the Nineties. But he was also inventing the new, though obviously related intellectual realm of biodiversity, the most persuasive and poetically convincing expression of environmentalism.
In The Diversity of Life, published in 1993, he charts the bewildering complexity and interdependence of life on the planet. It is a polemical work. Wilson fears that we might be approaching a wave of extinctions that could decisively reduce the level of biodiversity. Such extinctions have happened before. But in this case we are entirely responsible. Our activities, unlike those of most organisms, benefit no other species. In the rainforests, in particular, we are wiping out countless thousands of species, many of them unknown, and the effect of that may be to precipitate a domino effect that will wipe out thousands, maybe millions more.
We have no idea of the effect of such a mass extinction. It could destroy the whole ecosystem, or merely humanity. But we can't wait to find out. "One planet," he writes, "one experiment." There will be no second chances.
Wilson is 66 and at last the full force of his life's work is coming to be understood. Ecology, of which he was the greatest pioneer, is now one of the most powerful scientific and intellectual forces in the world. Sociobiology has escaped from the PC pirates and is a growing discipline. In such areas as evolutionary psychology, the interaction between culture and evolution is now studied. Biodiversity, the subject of a recent UN report, is the latest and most urgent obsession of environmentalists.
All this flowed from Wilson's accidental fascination with ants. It was accidental because at the age of eight he went fishing: he yanked a fish from the water and a fin pierced his eye, partially blinding him. His remaining sight was good for close-ups, bad for distances. He was obliged to study small rather than large animals and chose ants.
The image of a solitary boy peering at the minute details of nature has always clung to him. He is a loner and a poet. His work is personal and intense. Science begins and ends for him in primitive, private wonder.
"The best of science", he writes in The Diversity of Life, "doesn't consist of mathematical models and experiments ... Those come later. It springs fresh from more primitive modes of thought, wherein the hunter's mind weaves ideas from old facts and fresh metaphors and the scrambled crazy images of things recently seen."
This is not just a great thinker. This is a great man, the creator of a secular, materialistic myth, the true prophet of a new, humane and meaningful science.
4: Edward O Wilson
'My truths are the following: first, humanity is ultimately the product of biological evolution; second, the diversity of life is the cradle and greatest natural heritage of the human species; and third, philosophy and religion make little sense without taking into account the first two conceptions'
CAREER: Edward O Wilson is Pellegrino University Professor and curator in entomology at the Museum of Comparative Zoology, Harvard. He has been connected with Harvard since 1953. He was born in Birmingham, Alabama, in 1929. He has won more than 30 academic awards and prizes.
WORK: He is in effect the founder of a whole series of contemporary scientific disciplines - ecology, sociobiology, evolutionary psychology and biodiversity. His first two books were on the biology of islands and on insect societies. In 1975, he published 'Sociobiology: The New Synthesis' followed by 'On Human Nature' in 1978, which transferred his insight on animal behaviour into the human realm. 'The Diversity of Life', which warned about the dangers of mass extinction of species, appeared in 1992. Throughout he has continued to work as a field naturalist, producing monumental works on ants, his favourite animals.
LIFE: He has a wife and daughter, both of whom he studiously keeps out of the public eye.
CRITICS: In the mid-Seventies he was vilified and publicly abused by Harvard Marxists for his work in sociobiology, which they regarded as a racist, sexist defence of the status quo. Molecular biologists earlier dismissed the work of naturalists such as Wilson as "stamp collecting".