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.