Making sense of life : explanation in developmental biology

From the nineteenth century to the twenty-first, the meaning of life changed enormously, and with it the field of biology changed too. It can be said, though not everyone would agree, that biology got going as a subject when it distinguished life, not from death, but from inorganic processes. Around 1910, a Frenchman, Stéphane Leduc tried to close the conceptual gap between the living and the non-living with demonstrations of lifelike chemical forms. By selecting his colloids and solutions carefully, adjusting concentrations at appropriate stages, he was able to create rather nice " osmotic productions, " which look much like fungus: mushrooms and flowering bodies. Like real life, these artificially-created forms grew and sort-of reproduced. Some people got excited; others did not know whether to laugh or cry. Today, Leduc's ideas seem naïve, and indeed they never provided an explanation about life that people could work with. The story of life had to wait for genes, and that undermined Leduc's gene-free approach, along with several others. The creation of life, or perhaps rather the creation of lifelike forms, has ever since received a mixed reception. Today, it is trendy not to rely on chemical osmosis so much as computation. Artificial life has set itself the goal of studying how life emerges from appropriate organising principles, regardless of the medium it lives in. It does not have to be carbon-based, but if it is in a computer, so be it. Making Sense of Life is Evelyn Fox Keller's meditation on these issues. Some biologists would rather observe than build, and those that build have to use their words carefully. Artificial life does not really need nutrition or metabolism in the same way real life does. Such words as nutrition and competition are metaphors, and can inspire scientists to see more than is really there, or perhaps less. Why do species compete rather than collaborate? And when those metaphors are laden, as they are, with the burdens of culture and stereotypes about what scientists do, there is scope for even more debate. Mother Nature hides secrets from us, especially in embryology, and the quest to explore takes on masculine and elitist overtones. Making Sense of Life is divided into three clear parts, corresponding to historical periods. First, we have making sense of life without genes, which opens with Leduc and fizzles out with the untimely birth, as Keller puts it, of mathematical …