. It is
likewise necessary, there should be a relation of ideas. The beauty
of one person never inspires us with love for another. This then is a
sensible proof of the double relation of impressions and ideas. From one
instance so evident as this we may form a judgment of the rest.

This may also serve in another view to illustrate what I have insisted
on concerning the origin of pride and humility, love and hatred. I have
observed, that though self be the object of the first set of passions,
and some other person of the second, yet these objects cannot alone be
the causes of the passions; as having each of them a relation to two
contrary affections, which must from the very first moment destroy
each other. Here then is the situation of the mind, as I have already
described it. It has certain organs naturally fitted to produce a
passion; that passion, when produced, naturally turns the view to a
certain object. But this not being sufficient to produce the passion,
there is required some other emotion, which by a double relation of
impressions and ideas may set these principles in action, and bestow on
them their first impulse. This situation is still more remarkable with
regard to the appetite of generation. Sex is not only the object, but
also the cause of the appetite. We not only turn our view to it, when
actuated by that appetite; but the reflecting on it suffices to excite
the appetite. But as this cause loses its force by too great frequency,
it is necessary it should be quickened by some new impulse; and that
impulse we find to arise from the beauty of the person; that is, from a
double relation of impressions and ideas. Since this double relation is
necessary where an affection has both a distinct cause, and object,
how much more so, where it has only a distinct object, without any
determinate cause?

SECT. XII OF THE LOVE AND HATRED OF ANIMALS

But to pass from the passions of love and hatred, and from their
mixtures and compositions, as they appear m man, to the same affections,
as they display themselves in brutes; we may observe, not only that love
and hatred are common to the whole sensitive creation, but likewise that
their causes, as above-explained, are of so simple a nature, that they
may easily be supposed to operate on mere animals. There is no force of
reflection or penetration required. Every thing is conducted by springs
and principles, which are not peculiar to man, or any one species of