What Mad Pursuit: A Personal View of Scientific Discovery by Francis Crick (Basic Books: $16.95; 182 pages)
The discovery and unraveling of the genetic code in the last few decades ranks among the greatest achievements in the history of science.
Just as Newton and Einstein changed physics--and in the process changed our world views--James Watson and Francis Crick changed biology--with equally profound results. They showed that DNA is the secret of life, and they demonstrated that biology is a branch of chemistry.
Before Watson and Crick, most biologists investigated whole organisms, which they classified. This was no mean trick. Darwin was a great classifier, and his contribution to biology and to thought was enormous.
But Darwin didn't have a clue about the mechanism of heredity. That remained for Watson and Crick to explain. As a result of their work, biologists now deal with molecules--DNA, the molecule of heredity and of life.
It is startling to consider that until the last 40 years, most biologists did not think it either important or necessary to learn chemistry. As a result of the work of Watson and Crick, we now know that genetics is chemistry.
Watson gave his account of the discovery of the role of DNA in his remarkable book, "The Double Helix," published in 1968. The book created a tremendous stir at the time because it concentrated at least as much on the people involved as it did on the science they achieved.
Now comes Crick's book, "What Mad Pursuit," an elegant exposition that concentrates almost entirely on ideas and very little on personalities. It is about how science is done, the feel of it, the luck, thought and work involved.
"I enjoyed every moment of it, the downs as well as the ups," Crick writes of the crucial discovery he and Watson made. "I cannot do better than quote from a brilliant and perceptive lecture I heard years ago in Cambridge by the painter John Minton in which he said of his own artistic creations, 'The important thing is to be there when the picture is painted.' And this, it seems to me, is partly a matter of luck and partly good judgment, inspiration, and persistent application."
At this point, the details of the discovery are largely old hat, having been described, as Crick notes, not only by Watson but by Robert Olby ("The Path to the Double Helix") and Horace Freeland Judson ("The Eighth Day of Creation"). Still, it's important to get Crick's version of the crucial events.
More valuable is Crick's sense of the process of science. With hindsight, it's always tempting to show how things led inexorably up to the present moment, implying that the participants knew where they were going all along. Crick does not make this mistake.
"There were always nagging doubts that one or more of our assumptions might be dangerously misleading," he writes. "In research the front line is almost always in a fog."
Later on, Crick tells us that after he and Watson had figured out the structure of DNA, "although we were excited when we discovered the double helix, neither we nor anybody else thought of it as a wild success. Indeed, Jim worried that it might be all wrong and that we'd . . . made fools of ourselves."
The best part of the book begins with the penultimate chapter, titled, "Conclusions." In this chapter and the one that follows, Crick steps back from DNA and genetics to distill from them what he has learned about science and knowledge.
He is much interested in the structural differences between biology and physics. "The laws of physics, it is believed, are the same everywhere in the universe," he writes. "This is unlikely to be true of biology. We have no idea how similar extraterrestrial biology (if it exists) is to our own."
Similarly, physicists are guided by Occam's razor--the belief that simple explanations are better than complicated ones. "While Occam's razor is a useful tool in the physical sciences," Crick says, "it can be a very dangerous implement in biology. . . . Physicists are all too apt to look for the wrong sorts of generalizations, to concoct theoretical models that are too neat, too powerful, and too clean. . . . What seems to physicists to be a hopelessly complicated process may have been what nature found simplest, because nature could only build on what was already there."
And then Crick spends a chapter describing his current research at the Salk Institute in La Jolla. He is working on the problem of vision, a subject as shrouded in mystery as the molecular basis of genetics was when he began that work. He hopes for the second time in his life to come up with the ideas that will create a new science.