No More Learning

How this efficient cause is, in a sense,           to natural things, since it is nature itself; and how, in a sense, it is extrinsic to them; how the formal cause is joined to the efficient cause, and is that through which the efficient cause operates, and how the formal cause, itself, is brought forth from the womb of matter by the efficient cause; how the efficient and formal causes coin- cide in an elementary substratum, and how the one cause is distinct from the other.