it is regarded as affected by the idea of any given man, the whole order of nature as conceived under the attributes of extension and thought must be deducible. It would therefore follow (I. xxi.) that man is infinite, which (by the first part of this proof) is absurd. It is, therefore, impossible, that man should not undergo any changes save those whereof he is the adequate cause. Q.E.D.
Corollary.—Hence it follows, that man is necessarily always a prey to his passions, that he follows and obeys the general order of nature, and that he accommodates himself thereto, as much as the nature of things demands.
PROP. V. The power and increase of every passion, and its persistence in existing are not defined by the power, whereby we ourselves endeavour to persist in existing, but by the power of an external cause compared with our own.
Proof.—The essence of a passion cannot be explained through our essence alone (III. Deff. i. and ii.), that is (III. vii.), the power of a passion cannot