the Ideas and the mathematical numbers and some recognize both as having one nature, while some others say that the mathematical substances are the only substances, we must consider first the objects of mathematics, not qualifying them by any other characteristic not asking, for instance, whether they are Ideas or not, or whether they are the principles and substances of existing things or not, but only whether as the objects of mathematics they exist or not, and if they do, how they exist; then after this we must separately consider the Ideas themselves in a general way, and only as far as systematic treatment demands; for most of what we have to say has been repeatedly stated in popular works.