and not through an accident of his nature.
Corollary III.-It follows, thirdly, that God is the
absolutely first cause.

PROP. XVII. God acts solely by the laws of his own nature, and
is not constrained by anyone.
Proof.-We have just shown (in Prop. xvi.), that solely from
the necessity of the divine nature, or, what is the same thing,
solely from the laws of his nature, an infinite number of things
absolutely follow in an infinite number of ways ; and we proved
(in Prop. xv.), that without God nothing can be nor be conceived
; but that all things are in God. Wherefore nothing can exist
outside himself, whereby he can be conditioned or constrained to
act. Wherefore God acts solely by the laws of his own nature,
and is not constrained by anyone. Q.E.D.
Corollary I.-It follows : 1. That there can be no cause
which, either extrinsically or intrinsically, besides the
perfection of his own nature, moves God to act.
Corollary II.-It follows : 2. That God is the sole free
cause. For God alone exists by the sole necessity of his nature
(by Prop. xi. and Prop. xiv., Coroll. i.), and acts by the sole
necessity of his own nature, wherefore God is (by Def. vii.) the
sole free cause. Q.E.D.
Note.-Others think that God is a free cause, because he can,
as they think, bring it about, that those things which we have
said follow from his nature-that is, which are in his power,
should not come to pass, or should not be produced by him. But
this is the same as if they said, that God could bring it about,
that it should follow from the nature of a triangle that its
three interior angles should not be equal to two right angles ;