xvi.), that is (II.

xiii.), they agree with the nature of the mind; wherefore the knowledge of these ideas necessarily involves knowledge of the mind; but (by the last Prop.) the knowledge of these ideas is in the human mind itself; wherefore the human mind thus far only has knowledge of itself.

Q.E.D.
PROP.XXIV.

The human mind does not involve an adequate knowledge of the parts composing the human body.
Proof .-- The parts composing the human body do not belong to the essence of that body, except in so far as they communicate their motions to one another in a certain fixed relation (Def.
after Lemma iii.), not in so far as they can be regarded as individuals without relation to the human body.

The parts of the human body are highly complex individuals (Post.