The Lagoon: How Aristotle Invented Science

by Armand Marie Leroi

EVERY SCIENTIST HAS a conception of what constitutes ‘good science’. It is a sense, as firmly held as it is poorly articulated, of which causal claims are sound and which aren’t. It’s not, of course, that scientists necessarily agree on the soundness of any given claim. If you have ever contemplated the reviews of a manuscript, submitted with such hope to Nature or Science (for at the gates to these journals hope truly does spring eternal), you will know that your peers’ notions of what constitute sound causal claims are often very different from your own and really quite confused. Aristotle also faced the problem of securing causal knowledge from observation, but he faced it alone. Behind him lay generations of speculative theories about the causes of the natural world; at his feet stretched the world itself. He saw, and saw as no one before him had, the need for a way to connect them. So he developed one. In Book I of Historia animalium he alludes to it. First, he says, we have to get the facts about the different features of animals, then we have to work out their causes. Doing things in that order, he continues, will make the subject and target of our demonstrations clear. It seems like a rather banal introductory statement. It isn’t. For, when Aristotle talks of ‘demonstration’, he means an intellectual structure of daedal complexity whose foundations are sunk in metaphysical bedrock and whose pillars are constructed of steely formal logic. He means his scientific met...