BOOK I PART III
on the passions and imagination, proportioned
to that degree of force and vivacity, which they
communicate to the ideas. It is by habit we
make the transition from cause to effect; and
it is from some present impression we borrow
that vivacity, which we diffuse over the correl-
ative idea. But when we have not observed
a sufficient number of instances, to produce a
strong habit; or when these instances are con-
trary to each other; or when the resemblance is
not exact; or the present impression is faint and
obscure; or the experience in some measure
obliterated from the memory; or the connex-
ion dependent on a long chain of objects; or the
inference derived from general rules, and yet
not conformable to them: In all these cases the
evidence diminishes by the diminution of the
force and intenseness of the idea. This therefore
is the nature of the judgment and probability.