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

Proof.--Every idea of a modification of the human body
involves the nature of the human body, in so far as the human
body is regarded as affected in a given manner (II. xvi.). But,
inasmuch as the human body is an individual which may be affected
in many other ways, the idea of the said modification, &c.
Q.E.D.

PROP. XXVIII. The ideas of the modifications of the human body,
in so far as they have reference only to the human mind, are not
clear and distinct, but confused.

Proof.--The ideas of the modifications of the human body
involve the nature both of the human body and of external bodies
(II. xvi.); they must involve the nature not only of the human
body but also of its parts; for the modifications are modes
(Post. iii.), whereby the parts of the human body, and,
consequently, the human body as a whole are affected. But (by
II. xxiv., xxv.) the adequate knowledge of external bodies, as
also of the parts composing the human body, is not in God, in so
far as he is regarded as affected by the human mind, but in so
far as he is regarded as affected by other ideas. These ideas of
modifications, in so far as they are referred to the human mind
alone, are as consequences without premisses, in other words,
confused ideas. Q.E.D.

Note.--The idea which constitutes the nature of the human mind
is, in the same manner, proved not to be, when considered in
itself alone, clear and distinct; as also is the case with the
idea of the human mind, and the ideas of the ideas of the
modifications of the human body, in so far as they are referred
to the mind only, as everyone may easily see.

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

Proof.--The idea of a modification of the human body (II.
xxvii.) does not involve an adequate knowledge of the said body,
in other words, does not adequately express its nature; that is
(II. xiii.) it does not agree with the nature of the mind
adequately; therefore (I. Ax. vi) the idea of this idea does not
adequately express the nature of the human mind, or does not
involve an adequate knowledge thereof.

Corollary.--Hence it follows that the human mind, when it
perceives things after the common order of nature, has not an
adequate but only a confused and fragmentary knowle