THE WORLD-SOUL IS THE CONCEIVING-PRINCIPLE.
We have already noticed two of these principles (namely, intelligence, and the intelligible, which is called the Animal-in-itself, or universal Soul). What is the third? It is he who has resolved to produce, to form, to divide the ideas that intelligence sees in the Animal. Is it possible that in one sense intelligence is the dividing principle, and that in another the dividing principle is not intelligence? As far as divided things proceed from intelligence, intelligence is the dividing principle. As far as intelligence itself remains undivided, and that the things proceeding from it (that is, the souls) are divided, the universal Soul is the principle of this division into several souls. That is why Plato says that division is the work of a third principle, and that it resides in a third principle that has conceived; now, to conceive is not the proper function of intelligence; it is that of the Soul which has a dividing action in a divisible nature.