Daniel Kevles

  • Thinking about science: Max Delbrück and the Origins of Molecular Biology by Ernst Peter Fischer and Carol Lipson
    Norton, 334 pp, £13.95, January 1989, ISBN 0 393 02508 X
  • Is science necessary? Essays on Science and Scientists by Max Perutz
    Barrie and Jenkins, 285 pp, £14.95, July 1989, ISBN 0 7126 2123 7

In 1944, the physicist Erwin Schrödinger, who had earned a Nobel Prize for his contributions to the invention of quantum mechanics, published What is life?, a remarkable book in which he argued that vital processes must obey the laws of physics but could probably not be reduced to them. In micro-physics, order tended to give way to disorder; the behaviour of single atoms could be predicted only in statistical terms. In living organisms, the genes governing heredity and development seemed to consist of a particular arrangement of atoms. Yet, in essential respects, offspring resembled parents; order produced order. The apparent disparity between atomic and life-cycle events led Schrödinger to contend that a ‘new type of physical law’ – not a ‘super-physical’ but a ‘genuinely physical’ type, consistent with known physical laws – must prevail in living matter.

Schrödinger’s book, a tour de force in its demonstration of how physical reasoning might be applied to biological problems, stimulated a number of young physicists to enter the rapidly-burgeoning field of molecular biology. The French geneticist and Nobel laureate François Jacob recalled:

After the war, many young physicists were disgusted by the military use that had been made of atomic energy ... Some looked to biology with a mixture of diffidence and hope ... To hear one of the fathers of quantum mechanics ask himself, ‘What is life?’ and to describe heredity in terms of molecular structure, of inter-atomic bonds, of thermodynamic stability, sufficed to draw towards biology the enthusiasm of young physicists and to confer on them a certain legitimacy. Their ambitions and their interests were confined to a single problem: the physical nature of the genetic information.

It is likely, however, that Schrödinger’s book led more people to attack problems in biology than to search for new laws of physics. Schrödinger’s was the speculation of a theorist, and a philosophically-inclined one at that. Pure theory – the pursuit of first principles to logical consequences – has rarely figured in modern biological inquiry, at least not in its Anglo-American mode. To be sure, Charles Darwin – despite his protestations to the contrary – had strong theoretical inclinations, but he constantly tested and modified his ideas against an enormous array of observational data. Max Perutz, who was for many years the director of the Medical Research Council Unit for Molecular Biology at the Cavendish Laboratory in Cambridge, had a front-row seat during many innings of molecular genetics. He reports in Is science necessary? – a collection of engaging essays and reviews, including one occasioned by the 1987 reissue of What is life? – that few molecular biologists, including the recruits from physics, appear to have been much, if at all, concerned with the seemingly deep issue Schrödinger discussed. The pioneers of molecular biology may have imported analytical attitudes and techniques from the physical sciences, but they were problem-solvers, working at the laboratory bench to tease out the mechanism of heredity.

Perutz, who shared the 1962 Nobel Prize in Chemistry for his work on the structure and function of haemoglobin, more than once makes the point that the stuff of biology does not lie primarily in isolated thought but in the connection of thought with the details of observation and experiment. Like Schrödinger, Perutz is a native of Vienna, but he left in 1936 for postgraduate work at Cambridge, where he became imbued with the scientific values characterised, he says, by ‘extreme devotion to hard experimental work, and strong aversion to speculation beyond what is justified by the experimental results’. Peter Medawar once extolled imaginative guesswork as part of the scientific process. Perutz comments: ‘During the first 33 years of my own research imaginative guesswork proved useless: only after my colleagues and I had solved the structure of haemoglobin by X-ray analysis could I begin to guess how the molecule works.’

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