the human
body.

Proof.--Thought is an attribute of God (II. i.); therefore
(II. iii.) there must necessarily be in God the idea both of
thought itself and of all its modifications, consequently also of
the human mind (II. xi.). Further, this idea or knowledge of the
mind does not follow from God, in so far as he is infinite, but
in so far as he is affected by another idea of an individual
thing (II. ix.). But (II. vii.) the order and connection of
ideas is the same as the order and connection of causes;
therefore this idea or knowledge of the mind is in God and is
referred to God, in the same manner as the idea or knowledge of
the body. Q.E.D.

PROP. XXI. This idea of the mind is united to the mind in the
same way as the mind is united to the body.

Proof.--That the mind is united to the body we have shown from
the fact, that the body is the object of the mind (II. xii. and
xiii.); and so for the same reason the idea of the mind must be
united with its object, that is, with the mind in the same manner
as the mind is united to the body. Q.E.D.

Note.--This proposition is comprehended much more clearly from
what we have said in the note to II. vii. We there showed that
the idea of body and body, that is, mind and body (II. xiii.),
are one and the same individual conceived now under the attribute
of thought, now under the attribute of extension; wherefore the
idea of the mind and the mind itself are one and the same thing,
which is conceived under one and the same attribute, namely,
thought. The idea of the mind, I repeat, and the mind itself are
in God by the same necessity and follow from him from the same
power of thinking. Strictly speaking, the idea of the mind, that
is, the idea of an idea, is nothing but the distinctive quality
(forma) of the idea in so far as it is conceived as a mode of
thought without reference to the object; if a man knows
anything, he, by that very fact, knows that he knows it, and at
the same time knows that he knows that he knows it, and so on to
infinity. But I will treat of this hereafter.

PROP. XXII. The human mind perceives not only the modifications
of the body, but also the ideas of such modifications.

Proof.--The ideas of the ideas of modifications follow in God
in the same manner, and are referred to God in the same manner,
as the ideas of the said modifications. This is proved in the
same way as II. xx. But the ideas of the modifications of the
body are in