When I was a student I was enjoined to reject the "Cleopatra's Nose" theory of history, so called after Pascal's remark in the Pensées : "Cleopatra's nose: if it had been shorter, everything in the world would have changed." The intent was not to dismiss biography as a way into the structuring of a historical narrative, but to reject the idea that the properties, ideas, or actions of some particular person were the necessary conditions for the unfolding of events in the world. If Josef Djugashvili had never been born, someone else could have been Stalin.
Despite this injunction, a remarkable amount of the history of science has been written through the medium of biographies of "great" scientists to whose brilliant discoveries we owe our understanding of the material world, and this historical methodology has reinforced the common notion that history is made by outstanding individuals. No respectable historian would claim that if Newton had never been born we would still be ignorant about gravitation. Yet we still refer to the regularities of the behavior of physical bodies as "Newton's Laws," the general regularities of simple inheritance as "Mendelism," and the science of biological evolution as "Darwinism." Even the famous history of science written by the Marxist J.D. Bernal is a recounting of the discoveries and inventions of individuals.
It would be wrong to say that biography is the sole, or even principal, present pathway into an understanding of the history of science. Certainly since Robert Merton's founding of modern studies of the sociology of science in his 1938 work on seventeenth-century English science, the social milieu in which the problems of science arise and the institutional structure of scientific investigation have been central to our understanding of the history of scientific work. There are, however, occasions on which there are orgies of idolatrous celebrations of the lives of famous men, when the Suetonian ideal of history as biography overwhelms us. For Darwinians, 2009 is such a year.