In my opinion, the double helix is much too simple to be the secret of life. If DNA had been the secret of life, we should have been able to cure cancer long ago. The double helix explains replication but it does not explain metabolism. Delbrück chose to study the phage because it embodies replication without metabolism, and Crick and Watson chose to study DNA for the same reason. Replication is clean while metabolism is messy. By excluding messiness, they excluded the essence of life. The genomes of human and other creatures have now been completely mapped and the processes of replication have been thoroughly explored, but the mysteries of metabolism still remain mysteries.
The phage is still the only living creature whose behavior is simple enough to be completely understood and predicted. To understand other kinds of creatures, from fruit flies to humans, we need also a deep understanding of metabolism. The understanding of metabolism will perhaps be the theme of the next revolution in biology. I have already discussed in these pages a seminal paper by the biologist Carl Woese with the title "A New Biology for a New Century," pointing the way toward the next revolution. Woese's new biology is based on the idea that a living creature is a dynamic pattern of organization in the stream of chemical materials and energy that passes through it. Patterns of organization are constantly forming and reforming themselves. If we try to observe and localize every molecule as it passes through an organism, we are likely to destroy the patterns that constitute metabolic life. In Woese's picture of life, complementarity plays a central role, just as Bohr said it should.
At the same time, while Carl Woese and others are debating the future of biology, the great debate over the future of physics continues. It is still a debate over the same questions that caused the disagreement between Bohr and Einstein. Does the quantum theory of the 1920s, together with the standard model of particles and interactions that grew out of it, give us a solid foundation for understanding nature? Or do we need another revolution to reach a deeper understanding?
Theoretical physicists are now divided into two main factions. Those who look forward to another revolution mostly believe that it will grow out of a grand mathematical scheme known as string theory. Those who are content with the outcome of the old revolution are mostly studying more mundane subjects such as high-temperature superconductors and quantum computers. String theory may be considered to be the counterattack of those who lost the debate over complementarity in physics in Copenhagen in 1932. It is the revenge of the heirs of Einstein against the heirs of Bohr. The new discipline of systems biology, describing living creatures as emergent dynamic organizations rather than as collections of molecules, is the counterattack of those who lost the debate over complementarity in biology in 1953. It is the revenge of the heirs of Bohr against the heirs of Einstein.
Monday, October 15, 2007
The heirs of Bohr
At the New York Review of Books, Freeman Dyson reviews Gino Segre's Faust in Copenhagen. (Not available online to non-subscribers.) I am regrettably ill-equipped to evaluate some of his arguments, but at the very least I find his conclusions stirring (I fairly often wish I were a biologist, or doing something at least broadly speaking in the life sciences--neurology, epidemiology):