Taking the counterfactual turn

When philosophers look to the history of biology, they most often ask about what happened, and how best to describe it. They ask, for instance, whether molecular genetics subsumed the Mendelian genetics preceding it, or whether these two sciences have maintained rather messier relations. Here I wish to pose a question as much about what did not happen as what did. My concern is with the strength of the links between our biological science—our biology—and the particular history which brought that science into being. Would quite different histories have produced roughly the same science? Or, on the contrary, would different histories have produced other, quite different biologies?

I shall not endeavour to address the whole of biology or its history. I will concentrate on genetics, the headline-grabbing branch of biology in our time. The claims of this science on our future have given its history an unusually high public profile. Newspaper articles on the completed Human Genome Project came with timelines of genetic achievement, stretching back into the pre- Mendel mists, and forward to a future where, thanks to geneticsbased medicine (we were told), the average person will live to more than ninety. Even more recently, the fiftieth anniversary of the introduction of the double-helix model of DNA in 1953 prompted books, symposia, television programmes, even a cover story in Time magazine. It also spurred people to wonder out loud about the nature of history. In 2003, we celebrated James Watson and Francis Crick above all. But they inferred the structure of DNA from Rosalind Franklin's remarkable X-ray crystallographic photograph of the B form of DNA.