3. About the Third Reason

67. The third initial reason [n.25] does not conclude. For either it assumes in the major that the secondary agent presupposes the effect of the first agent as the matter on which it acts, and then it begs the question, namely that every agent other than God acts on some presupposed passive thing. Or it understands the major absolutely, namely that a secondary agent does absolutely presuppose an effect of the first agent, which I concede, because of course it presupposes itself, just as acting presupposes being, and being is the effect of the first agent.

68. As to the induction [n.25], which seems to prove the minor according to the first way of taking the major [n.67], I say that if art has power for some form yet it only has power for some merely accidental form. But an accident necessarily requires a substance for its actual subject. So what follows is not that an artisan (by the fact he is an agent subordinate to nature) requires or presupposes an effect of nature as his own passive subject, but rather that he acts for the sort of term that requires a substance, and art has no power to produce a substance. But it is very plain that this is not because of an order of agents, for nature presupposes in its action an effect of nature as its passive subject, just as in the case of alteration it presupposes a substance. Therefore, there is a common cause on the part of nature and on the part of art in presupposing a substance, namely when they act to produce an accident that can only be produced in a substance.

69. But if some corporeal substance were immediately produced by God without any action of nature, art could nevertheless act on the passivity of it, provided the corporeal substance were capable of the term of the art and provided the effect of nature had preceded in it.

70. It is likewise plain that the argument from the order of agents [n.25], by distinguishing several orders of agents, is not valid. For in the order of natural agent one can find a material agent that is lower and an immaterial agent that is higher. But it does not follow that the material agent presupposes the effect of a created immaterial agent; nor does it follow that, if the material agent presupposes an effect of God immediately on which it acts, therefore the immaterial agent, which is higher, presupposes nothing.