But if we compare together all the phenomena that occur on this head,
we shall find, that truth, however necessary it may seem in all works
of genius, has no other effect than to procure an easy reception for the
ideas, and to make the mind acquiesce in them with satisfaction, or at
least without reluctance. But as this is an effect, which may easily be
supposed to flow from that solidity and force, which, according to
my system, attend those ideas that are established by reasonings from
causation; it follows, that all the influence of belief upon the fancy
may be explained from that system. Accordingly we may observe, that
wherever that influence arises from any other principles beside truth or
reality, they supply its place, and give an equal entertainment to
the imagination. Poets have formed what they call a poetical system of
things, which though it be believed neither by themselves nor readers,
is commonly esteemed a sufficient foundation for any fiction. We have
been so much accustomed to the names of MARS, JUPITER, VENUS, that
in the same manner as education infixes any opinion, the constant
repetition of these ideas makes them enter into the mind with facility,
and prevail upon the fancy, without influencing the judgment. In like
manner tragedians always borrow their fable, or at least the names of
their principal actors, from some known passage in history; and that not
in order to deceive the spectators; for they will frankly confess, that
truth is not in any circumstance inviolably observed: but in order
to procure a more easy reception into the imagination for those
extraordinary events, which they represent. But this is a precaution,
which is not required of comic poets, whose personages and incidents,
being of a more familiar kind, enter easily into the conception, and are
received without any such formality, even though at first night they be
known to be fictitious, and the pure offspring of the fancy.