The Lagoon: How Aristotle Invented Science

by Armand Marie Leroi

Aristotle wrote a whole book about the soul, de Anima, or The Soul. Devoid of Platonic moralizing, it is resolutely scientific in tone: Some types of knowledge may be especially fine and worthwhile for their precision or because their objects have greater value and elicit greater wonder. It is for both these reasons that we should treat the study of the soul as one of extreme importance. However its investigation seems to be of special importance for truth as a whole and the study of nature in particular. For souls are the principle of animal life. This, to us, is a very strange, even suspect, claim. ‘Soul’ is a word burdened with many meanings but none in modern science. Perhaps we would do better to abandon translation, but mere transliteration hardly helps matters at all. For us, ‘psyche’ refers to mental states – in particular, consciousness. To be sure, Aristotle does treat mental states in his book, but he treats them as physiology: the Cartesian problem of consciousness hardly arises. Indeed, The Soul is not a psychological treatise at all, but his most general statement about the systems of command and control that enable living things to do what they do. Aristotle asserts, with fairly little argument, two propositions: that all living things – plants, animals and humans – have souls; and that, when a living thing dies, its soul ceases to exist. These were probably commonplace among fourth-century Greek intellectuals. Plato clearly believes the first and has to arg...