How is that?
Why, because the one if equal must be of the same measures as that to which it is equal.
True.
And if greater or less than things which are commensurable with it, the one will have more measures than that which is less, and fewer than that which is greater?
Yes.
And so of things which are not commensurate with it, the one will have greater measures than that which is less and smaller than that which is greater.
Certainly.
But how can that which does not partake of sameness, have either the same measures or have anything else the same?
Impossible.
And not having the same measures, the one cannot be equal either with itself or with another?