One person is a one, and a being. No person is none, or zero. These are the first two numbers, and the first two concepts in metaphysics and in science and thought altogether. In a systematization of reality they are the first two terms. The next concept in metaphysics is relation, which occurs if two beings are somehow united.
Relation corresponds to the number two.
Its relation to being and nothingness is the same as the relation of two to one and zero. And of them, the relation of being to nothingness is the same as the relation of one to zero. Given a relation, the next thing that can arise beyond relation is potential so Aristotle argues, and asserts that there can be no other consequence, no other sequence, no intervening terms. The next metaphysical concept is actual which can only occur if there is potential, though there can be potential that is not used. This corresponds exactly to the fact that there can be no 4 without 3, but there can be 3 without 4.