y of these
rectangles be said to exist, except in so far as they are
comprehended in the idea of the circle. Let us grant that, from
this infinite number of rectangles, two only exist. The ideas of
these two not only exist, in so far as they are contained in the
idea of the circle, but also as they involve the existence of
those rectangles; wherefore they are distinguished from the
remaining ideas of the remaining rectangles.

PROP. IX. The idea of an individual thing actually existing is
caused by God, not in so far as he is infinite, but in so far as
he is considered as affected by another idea of a thing actually
existing, of which he is the cause, in so far as he is affected
by a third idea, and so on to infinity.

Proof.--The idea of an individual thing actually existing is
an individual mode of thinking, and is distinct from other modes
(by the Corollary and note to Prop. viii. of this part); thus
(by Prop. vi. of this part) it is caused by God, in so far only
as he is a thinking thing. But not (by Prop. xxviii. of Part i.)
in so far as he is a thing thinking absolutely, only in so far as
he is considered as affected by another mode of thinking; and he
is the cause of this latter, as being affected by a third, and so
on to infinity. Now, the order and connection of ideas is (by
Prop. vii. of this book) the same as the order and connection of
causes. Therefore of a given individual idea another individual
idea, or God, in so far as he is considered as modified by that
idea, is the cause; and of this second idea God is the cause, in
so far as he is affected by another idea, and so on to infinity.
Q.E.D.

Corollary.--Whatsoever takes place in the individual object of
any idea, the knowledge thereof is in God, in so far only as he
has the idea of the object.

Proof.--Whatsoever takes place in the object of any idea, its
idea is in God (by Prop. iii. of this part), not in so far as he
is infinite, but in so far as he is considered as affected by
another idea of an individual thing (by the last Prop.); but (by
Prop. vii. of this part) the order and connection of ideas is the
same as the order and connection of things. The knowledge,
therefore, of that which takes place in any individual object
will be in God, in so far only as he has the idea of that object.
Q.E.D.

PROP. X. The being of substance does not appertain to the
essence of man--in other words, substance does not constitute the
actual being[