s he
constitutes the essence of the human mind, but also in so far as
he, simultaneously with the human mind, has the further idea of
another thing, we assert that the human mind perceives a thing in
part or inadequately.

Note.--Here, I doubt not, readers will come to a stand, and
will call to mind many things which will cause them to hesitate;
I therefore beg them to accompany me slowly, step by step, and
not to pronounce on my statements, till they have read to the
end.

PROP. XII. Whatsoever comes to pass in the object of the idea,
which constitutes the human mind, must be perceived by the human
mind, or there will necessarily be an idea in the human mind of
the said occurrence. That is, if the object of the idea
constituting the human mind be a body, nothing can take place in
that body without being perceived by the mind.

Proof.--Whatsoever comes to pass in the object of any idea,
the knowledge thereof is necessarily in God (II. ix. Coroll.), in
so far as he is considered as affected by the idea of the said
object, that is (II. xi.), in so far as he constitutes the mind
of anything. Therefore, whatsoever takes place in the object
constituting the idea of the human mind, the knowledge thereof is
necessarily in God, in so far as he constitutes the essence of
the human mind; that is (by II. xi. Coroll.) the knowledge of
the said thing will necessarily be in the mind, in other words
the mind perceives it.

Note.--This proposition is also evident, and is more clearly
to be understood from II. vii., which see.

PROP. XIII. The object of the idea constituting the human mind
is the body, in other words a certain mode of extension which
actually exists, and nothing else.

Proof.--If indeed the body were not the object of the human
mind, the ideas of the modifications of the body would not be in
God (II. ix. Coroll.) in virtue of his constituting our mind, but
in virtue of his constituting the mind of something else; that
is (II. xi. Coroll.) the ideas of the modifications of the body
would not be in our mind: now (by II. Ax. iv.) we do possess the
idea of the modifications of the body. Therefore the object of
the idea constituting the human mind is the body, and the body as
it actually exists (II. xi.). Further, if there were any other
object of the idea constituting the mind besides body, then, as
nothing can exist from which some effect does not follow (I.
xxxvi.) there would necessarily have to be in ou