Full Idea
Mathematics does not take perceptible entities as its domain just because its subject-matter is accidentally perceptible; but neither does it take as its domain some other entities separable from the perceptible ones.
Gist of Idea
Mathematics studies the domain of perceptible entities, but its subject-matter is not perceptible
Source
Aristotle (Metaphysics [c.324 BCE], 1078a03)
Book Reference
Aristotle: 'Metaphysics', ed/tr. Lawson-Tancred,Hugh [Penguin 1998], p.399
A Reaction
This implies a very naturalistic view of mathematics, with his very empiricist account of abstraction deriving the mathematical concepts within the process of perceiving the physical world. And quite right too.