BOOK I PART III
and an idea, they must of consequence be the
source of all the differences in the effects of
these perceptions, and their removal, in whole
or in part, the cause of every new resemblance
they acquire. Wherever we can make an idea
approach the impressions in force and vivac-
ity, it will likewise imitate them in its influence
on the mind; and vice versa, where it imitates
them in that influence, as in the present case,
this must proceed from its approaching them
in force and vivacity. Belief, therefore, since it
causes an idea to imitate the effects of the im-
pressions, must make it resemble them in these
qualities, and is nothing buta more vivid and in-
tense conception of any idea. This, then, may both
serve as an additional argument for the present
system, and may give us a notion after what
manner our reasonings from causation are able
to operate on the will and passions.