  Perceptible magnitudes have perceptible matter. A bronze sphere is a perceptible magnitude. For solving the plurality problem, Aristotle needs to have many triangles with the same form. Since perceptible matter is not part of the object considered (in abstraction or removal), he needs to have a notion of matter which is the matter of the object: bronze sphere MINUS bronze (perceptible matter). Since this object must be a composite individual to distinguish it from other individuals with the same form, it will have matter. He calls such matter intelligible or mathematical matter. Aristotle has at least four different conceptions of intelligible matter in the middle books of the Metaphysics, Physics iv, and De anima i: 