Podium TOBY GREEN: We still have a lesson to learn from Darwin

From a speech by the author of `Travels with Darwin' to the Royal Geographical Society

WHEN IT comes to the germination of great ideas, it can be difficult to see the relevance of physical experience. Yet although Charles Darwin's later years were characterised by scholarship, it was his formative travelling years that were the key to his ideas.

Darwin's thoughts developed during the five years that he was circumnavigating the globe aboard HMS Beagle. On his return to England he had the seeds of a theory that has, more than anything else, contributed to the controversial moral questions that have dominated this century.

The changes in Darwin's thoughts were the result of his experience in the field. By far the most important strand of this was his shift towards Lyellian geology, which held that the date of the Creation was immeasurably more ancient than the 4004BC proposed by Archbishop Ussher. This shift in Darwin's ideas came about because of three central experiences: the discovery of an extraordinary array of fossils on the beach at Punta Alta; his experience of an earthquake and tidal wave in southern Chile; and his observation of a stand of fossilised trees in the Andes, which he was sure had once been at sea level.

Twenty-three years after returning home, Darwin published The Origin of Species. He did so only because of the threat of someone else beating him to publication. In one of the best-known episodes of scientific history, Darwin received a letter and article from Alfred Russel Wallace in the East Indies, in which Wallace propounded a version of the theory of evolution by natural selection identical to Darwin's. The two papers were first read together, but Darwin then published his book to great acclaim, and the theory became known as Darwinism.

Yet it was not until well into the 20th century that the idea of natural selection became popular. Evolution itself was swiftly accepted by much of the Establishment, for it was not all that unpalatable; progressive Victorians were happy to think of themselves as the peak of the evolutionary graph. However, natural selection, with the apparently arbitrary element of genetic mutation its centre-piece, was far more controversial. Naturally, two of the theory's most staunch defendants at the start were Darwin and Wallace; it had been their idea in the first place.

There was a common element in their experience. Both men had long studied the wildlife of places that had been little documented before. While Darwin had circumnavigated the globe, Wallace had spent long periods in South America and the East Indies. It was their experiences in the field that convinced them that natural selection was central to evolution. The significance of the giant tortoises in the Galapagos did not strike Darwin for some years after his return to Britain, but his recollection of them was eventually crucial in confirming his new ideas. For Wallace, the key was the behaviour of a bird that he had observed in the East Indies. For both, the essential element in their new idea was their personal experience.

These two scientists remained humanists through their lives, never able to forget the human warmth that had accompanied their adventures. It is important that we should not forget this today, when some contemporary dogmas attempt to identify human altruism and moral behaviour with the concepts of kin selection and intrinsic self-interest. The fact that these dogmas have been born in one of the most materialist cultures that the world has seen, would not have escaped Darwin. It is, after all, quite plausible that many interpretations of biological determinism are substantially the result of the experience of a culture that promotes the ego and materialist interpretations of reality.

Darwin, with his deep love of his family and the enduring memories of people far away who had assisted him in his voyage of discovery, knew that people were more than mere numbers. Few today can match his breadth of human experience and, judging by recent events and the priority given by some to economic ideas over human rights, his humanism appears to be a lesson that we have still to learn.