ence thereof (I.
xxxiv.). This was our first point. Again, if it were possible,
that man should undergo no changes save such as can be understood
solely through the nature of man, it would follow that he would
not be able to die, but would always necessarily exist; this
would be the necessary consequence of a cause whose power was
either finite or infinite; namely, either of man's power only,
inasmuch as he would be capable of removing from himself all
changes which could spring from external causes; or of the
infinite power of Nature, whereby all individual things would be
so ordered, that man should be incapable of undergoing any
changes save such as tended towards his own preservation. But
the first alternative is absurd (by the last Prop., the proof of
which is universal, and can be applied to all individual things).
Therefore, if it be possible, that man should not be capable of
undergoing any changes, save such as can be explained solely
through his own nature, and consequently that he must always (as
we have shown) necessarily exist; such a result must follow from
the infinite power of God, and consequently (I. xvi.) from the
necessity of the divine nature, in so far as 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 be defined by the power, whereby we
ourselves endeavour to persist in existing, but (as is shown in
II. xvi.) must necessarily be defined by the power of an external
cause compared with our own. Q.E.D.

PROP. VI. The force of any passion or emotion c