The Lagoon: How Aristotle Invented Science

by Armand Marie Leroi

Aristotle considers how a woodcarver might explain his art. He clearly wouldn’t just talk about the wood – that’s merely the matter out of which it’s built. Nor would he just talk about his axe and auger – they’re merely tools. Nor would he just talk about the strokes that he makes – that’s mere technique. No, if he is really to convey the origin of the thing he’s making, he has to talk about the idea that he had when he began his work – the process by which it will unfold in his hands, its final design and ultimate purpose – he must talk about its eidos. In the same way, when a scientist seeks to explain why living things have the features they do, he must talk about their eidē. It’s just that the forms of living things are not, as Plato held, located in the mind of some divine craftsman, but rather located in their parents’ seeds. There’s a passage in the Metaphysics where Aristotle gives another metaphor for the relationship between material and formal natures. Rather marvellously, he compares the components of a body to a symbolic system. Some things, he says, are compounds. The syllable ab is a compound of the letters a and b. But putting a and b together is not enough to give you that particular syllable; you need something else: you need to specify the order of the letters (lest you get ba instead) or, as we would now say, you need information. In the same way, flesh is a compound of fire and earth and something else: the way in which they are ordered. And that orde...