Challenges of life's science

‘I want to ground my discussion of explanation in biology in that which leads biologists to say Aha!’ says Evelyn Fox Keller, professor of the history and philosophy of science at the Massachusetts Institute of Technology. Keller is fascinated by biologists’ explanations of their work. But she is also interested in how biologists have managed to be so extraordinarily successful over the past century with such a challenge from physical science to account for biological phenomena. She considers that the origin of biology as a separate subject can be linked back to Lamarck. His Zoological Philosophy, written in 1809, was an enquiry into the physical causes which give rise to the phenomena of life. He wrote ‘Nature has no need for special laws, those which generally control all bodies are perfectly sufficient for the purpose.’ However, ‘if we wish to arrive at a real knowledge of... what are the causes and laws which control so wonderful a natural phenomenon, and how life itself can originate those numerous and astonishing phenomena exhibited by living bodies, we must above all pay very close attention to the differences existing between inorganic and living bodies.’ In doing so, Lamarck found that ‘between crude or inorganic bodies and living bodies there exists an immense difference, a great hiatus, in short, a radical distinction such that no inorganic body whatever can even be approached by the simplest of living bodies’. But Keller’s focus begins at the beginning of the last century when the question of what is life was being asked with increasing urgency, along with such companion phrases as the ‘riddle of life’, or ‘secret of life’. She believes such questions were understood increasingly as provocation, as demanding an answer, a solution. ‘Is the demarcation between the living and the non-living so categorical as to admit no intermediates, no bridges that might link the two domains,’ she asks. She describes the work of the French chemist Stéphane Leduc, who used a range of inorganic chemicals to create life-like forms of mushrooms and hydra-type organisms. For a brief period in the first two decades of the twentieth century it attracted Features