The Privilege of Quantities

We will grant that numbers are quantities, although if their nature of being quantities were plain, one would not see why they should be given that name. We must here not consider what is quantity by accident, but by its quantitativeness, quantity itself. As to the line, the surface, and the body, they are called sizes and not quantities, and the latter name is given them only when they are estimated numerically. A body is a quantity only insofar as it is measured, just as space is a quantityonly by accident and not by its spatiality. In this case, the quantity is the number found in them.