in some translations of the Timaeus) upon chaotic matter. Physical things thus only participate to some degree in the perfection of Plato's paradigmatic Forms. Aristotle, on the other hand, holds that substantial forms actualize the potency of prime matter made receptive by agents of change. The chick's substantial form actualizes prime matter that has been individualized into being a receptive potency for the chicken's substantial form by the hen and the rooster.

While the concept of substantial