‘Francis,” wrote James Watson in his book The Double Helix, “winged into the Eagle to tell everyone within hearing distance that we had found the secret of life.”

The Eagle is a pub in Cambridge. With the aid of Abbot Ale, I too have often found the secret of life there. It was in March 1953 that Francis Crick, who died last week at the age of 88, had “winged” in there to announce his discovery of life’s secret — the molecular structure of DNA. Brilliant, arrogant and tactless, he was 36 years old and for two years had been working in partnership with Watson, a 25-year-old American.

Their specific project was the deciphering of the structure of DNA, a long and apparently boring molecule found in living cells. But their true project was the overthrow of religion. Both, as Watson has explained to me, were militant atheists and they wished, by exposing the material basis of life, to reveal that there was no transcendent trickery involved.

Life was extraordinarily well organised matter, but it was still just matter. The mechanism of its organisation was explained by Darwin, the details were worked out by Gregor Mendel and, finally, by Watson and Crick.

What they found was, on the face of it, staggeringly simple and weirdly topical. The search for the genetic messenger — the material that transmitted characteristics down the generations — had been long and fraught. Neither Darwin nor Mendel had any idea what was involved; indeed, Mendel’s discoveries about inheritance in plants were, at first, taken to be a refutation of Darwin.

DNA, first discovered in the late 19th century, had usually been dismissed as a possible candidate precisely because it looked so simple and boring. Life was complex and so it was assumed that the messenger must be something equally complex, like, for example, proteins.

But the molecule unravelled by Watson and Crick simply consisted of four chemical “letters” — ACGT — repeated over and over again in various combinations, three billion times in the case of human DNA. This was topical because it happened at a time when we were just beginning to realise how complexity could arise from simplicity.

Information theory, the foundation of modern computing, had just got under way and the first gigantic computers were crunching numbers in a few very advanced laboratories. Those computers, as well as the tiny super-complex ones we use today, deployed only two digits — 0 and 1 — and yet they proved capable of immensely sophisticated and rapid operations.

The obvious point to make here is that ever since the birth of modern science, when Galileo first looked through a telescope in 1609, we have tended to see life in terms of the dominant machine of the day.

The most exact analogy for the Watson and Crick discovery was the discovery of the circulation of the blood by William Harvey in the 17th century. Suddenly the body looked like a hydraulic system and with the advent of the industrial revolution of the 18th century, and its vast lifelike machines, the possibility that we were a similar system of pulleys, pumps, tubes, levers, camshafts, fuel and waste was born.

Yet vitalism — the belief that there is something special about the stuff of life — persisted in the minds of most people. This was partly because, amazing as these new machines were, they displayed none of the strange autonomy and complexity of living things. But it was also because of the human brain. It was one thing to see animals as machines, as Descartes had, but quite another to see ourselves in the same way. We were self-conscious, reflective and apparently possessed of free will; how could such a creature emerge from ordinary matter? Descartes said that unlike animals we had a soul which, weirdly, he located in the pineal gland in the brain.

The question of how human consciousness arises from matter, in spite of a deluge of propaganda to the contrary, has not actually been answered. We still have no idea whatsoever how matter becomes conscious. We are not even sure what the question means. Yet the model of the computer convinced many that it was, in principle, answerable. Both DNA and the computer’s binary code showed that layers of ever greater complexity could be constructed from the simplest elements.

The power of this idea led to a new scientistic triumphalism that is still with us. Crick, for example, produced a strange book in 1994 called The Astonishing Hypothesis. What, he said, was astonishing was that identity and free will are nothing more than “a vast assembly of nerve cells”. Why such a blank statement of an ancient scientific orthodoxy should be astounding to anybody was never explained. In addition, we have had the hard scientistic propaganda of Stephen Hawking and Richard Dawkins. The latter’s “selfish gene” hypothesis turns the human being into a mere gene- replicating machine. Such strange fetishisation of the gene has proved to be one of the most bizarre and implausible post- Christian cults.