The One and The Many: Aristotle on The Individuation of Numbers

In Book K of the Metaphysics Aristotle raises a problem about a very persistent concern of Greek philosophy, that of the relation between the one (τ⋯ ἓν) and the many (τ⋯ πλ***θ***), but in a rather peculiar context. He asks: ‘What on earth is it in virtùe of which mathematical magnitudes are one? It is reasonable that things around us [i.e. sensible things] be one in virtue of [their] ψνχ⋯ or part of their ψνχ⋯, or something else; otherwise there is not one but many, the thing is divided up. But [mathematical] objects are divisible and quantitative. What is it that makes them one and holds them together?’ (1077 a 20–4).