We have dealt with the first two; but the third — this Principle which decides to work upon the objects [the Ideas] contemplated by the Intellectual-Principle within the Essentially-Living, to create them, to establish them in their partial existence — what is this third?
It is possible that in one aspect the Intellectual-Principle is the principle of partial existence, while in another aspect it is not.
The entities thus particularized from the unity are products of the Intellectual-Principle which thus would be, to that extent, the separating agent. On the other hand it remains in itself, indivisible; division begins with its offspring which, of course, means with Souls: and thus a Soul — with its particular Souls — may be the separative principle.
This is what is conveyed where we are told that the separation is the work of the third Principle and begins within the Third: for to this Third belongs the discursive reasoning which is no function of the Intellectual-Principle but characteristic of its secondary, of Soul, to which precisely, divided by its own Kind, belongs the Act of division.