BOOK I PART III
ing proceeds in some measure from reflection
andgeneral rules. We observe, that the vigour of
conception, which fictions receive from poetry
and eloquence, is a circumstance merely acci-
dental, of which every idea is equally suscep-
tible; and that such fictions are connected with
nothing that is real. This observation makes us
only lend ourselves, so to speak, to the fiction:
But causes the idea to feel very different from
the eternal established persuasions founded on
memory and custom. They are somewhat of
the same kind: But the one is much inferior to
the other, both in its causes and effects.
A like reflection on general rules keeps us
from augmenting our belief upon every en-
crease of the force and vivacity of our ideas.
Where an opinion admits of no doubt, or op-
posite probability, we attribute to it a full con-