That Aristotle, in common with the plain man, held every man's intelligence to be in him, of him, and his, and not extrinsic to him, I think is evident from these citations. On the other hand, that Aristotle did not take these separate human intelligences somehow to be effluxes of one great Intelligence, to which they returned, and were re-united with it in death, is not so clear. We are at a loss to assign his exact meaning in such passages as De anima, II, iii, 5; III, v, 3; and especially De gen. animal, II, iii, 10. leipetai de ton noun monon thurathen epeisienai kai theion einai monon (the conclusion remains, that intelligence alone comes in from without and is alone divine). Some pre-existence of the intellectual soul seems necessary in the Aristotelian system, as Aristotle nowhere recognises the notion of creation out of nothing, any more than Plato. He differs from Plato in being opposed to the transmigration of souls (De anima, I, iii, 26); and in his reticence upon a point upon which Plato was very explicit, the individuality of separate souls after death.
Of God and His Creatures: 2.61