If continuous quantity be quantity as far as it is continuous, then definite quantity will no longer be quantity. If, on the contrary, continuous quantity be quantity only accidentally, then there is nothing in common between continuous and definite quantity. 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. 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; as when, for instance, they are measured by two or three feet.[249] A body is a quantity only in so far as it is measured, just as space is a quantity only by accident, and not by its spatiality. We must here not consider what is quantity by accident, but by its quantitativeness, quantity itself. Three oxen are not a quantity; in this case, the quantity is the number found in them. Indeed, three oxen belong already to two categories. The case is similar with the line, and the surface, both of which possess such quantity. But if the quantity of surface be quantity itself, why would surface itself be a quantity? It is no doubt only when determined by three or four lines that the surface is called a quantity. NUMBERS ARE NOT QUANTITY IN ITSELF. Shall we then say that numbers alone are quantity? Shall we attribute this privilege to Numbers in themselves, which are beings, because they exist in themselves?[250] Shall we grant the same privilege to numbers existing in things which participate in them, and which serve to number, not unities, but ten oxen, for example, or ten horses? First, it would seem absurd that these numbers should not be beings, if the former ones be such. Then, it will seem equally absurd that they should exist within the things they measure, without existing outside them,[251] as the rules and instruments which serve to measure exist outside of the objects they measure. On the other hand, if these numbers that exist in themselves serve to measure, and nevertheless do not exist within the objects that they measure, the result will be that these objects will not be quantities since they will not participate in quantity itself. NUMBER IS NOT IN QUANTITY; BUT QUANTITY IS IN NUMBER.