in the
order of nature to the aforesaid part (II. vii.). We may affirm
the same thing of each part of each individual composing the
human body; therefore, the knowledge of each part composing the
human body is in God, in so far as he is affected by very many
ideas of things, and not in so far as he has the idea of the
human body only, in other words, the idea which constitutes the
nature of the human mind (II. xiii); therefore (II. xi.
Coroll.), the human mind does not involve an adequate knowledge
of the human body. Q.E.D.

PROP. XXV. The idea of each modification of the human body does
not involve an adequate knowledge of the external body.

Proof.--We have shown that the idea of a modification of the
human body involves the nature of an external body, in so far as
that external body conditions the human body in a given manner.
But, in so far as the external body is an individual, which has
no reference to the human body, the knowledge or idea thereof is
in God (II. ix.), in so far as God is regarded as affected by the
idea of a further thing, which (II. vii.) is naturally prior to
the said external body. Wherefore an adequate knowledge of the
external body is not in God, in so far as he has the idea of the
modification of the human body; in other words, the idea of the
modification of the human body does not involve an adequate
knowledge of the external body. Q.E.D.

PROP. XXVI. The human mind does not perceive any external body
as actually existing, except through the ideas of the
modifications of its own body.

Proof.--If the human body is in no way affected by a given
external body, then (II. vii.) neither is the idea of the human
body, in other words, the human mind, affected in any way by the
idea of the existence of the said external body, nor does it in
any manner perceive its existence. But, in so far as the human
body is affected in any way by a given external body, thus far
(II. xvi. and Coroll.) it perceives that external body. Q.E.D.

Corollary.--In so far as the human mind imagines an external
body, it has not an adequate knowledge thereof.

Proof.--When the human mind regards external bodies through
the ideas of the modifications of its own body, we say that it
imagines (see II. xvii. note); now the mind can only imagine
external bodies as actually existing. Therefore (by II. xxv.),
in so far as the mind imagines external bodies, it has not an
adequate knowledge of them. Q.E.D.