Six Articles)

We have now to consider the action of the corporeal creature; and
fate, which is ascribed to certain bodies. Concerning corporeal
actions there are six points of inquiry:

(1) Whether a body can be active?

(2) Whether there exist in bodies certain seminal virtues?

(3) Whether the heavenly bodies are the causes of what is done here
by the inferior bodies?

(4) Whether they are the cause of human acts?

(5) Whether demons are subject to their influence?

(6) Whether the heavenly bodies impose necessity on those things
which are subject to their influence?
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FIRST ARTICLE [I, Q. 115, Art. 1]

Whether a Body Can Be Active?

Objection 1: It would seem that no bodies are active. For Augustine
says (De Civ. Dei v, 9): "There are things that are acted upon, but
do not act; such are bodies: there is one Who acts but is not acted
upon; this is God: there are things that both act and are acted upon;
these are the spiritual substances."

Obj. 2: Further, every agent except the first agent requires in its
work a subject susceptible of its action. But there is not substance
below the corporeal substance which can be susceptible of the
latter's action; since it belongs to the lowest degree of beings.
Therefore corporeal substance is not active.

Obj. 3: Further, every corporeal substance is limited by quantity.
But quantity hinders substance from movement and action, because it
surrounds it and penetrates it: just as a cloud hinders the air from
receiving light. A proof of this is that the more a body increases in
quantity, the heavier it is and the more difficult to move. Therefore
no corporeal substance is active.

Obj. 4: Further, the power of action in every agent is according to
its propinquity to the first active cause. But bodies, being most
composite, are most remote from the first active cause, which is most
simple. Therefore no bodies are active.

Obj. 5: Further, if a body is an agent, the term of its action is
either a substantial, or an accidental form. But it is not a
substantial form; for it is not possible to find in a body any
principle of action, save an active quality, which is an accident;
and an accident cannot be the cause of a substantial form, since the
cause is always more excellent than the effect. Likewise, neither is
it an accidental form, for "an accident does not extend beyond its
subject," as Augustine says (De Trin. ix, 4). Therefore no bodies