 This does not look like a mathematically (or philosophically) interesting conception of perfect numbers, and the same is true of the other points Speusippus makes in favor of the perfection of the number 10. But it does incorporate one feature of great interest: on the face of it, if Speusippus thinks that within the number 10 there are just as many odd as even numbers, he must be counting 1 as an odd number, and therefore a number. (The alternative, which actually must finally be considered seriously, is that he is not counting 2 as a number, either, but this does not seem likely.) That makes him, as already noted, an exception in his time and place.