xv.) a cause of pleasure or pain.

Thus (by the foregoing Corollary), although the point in which the two objects resemble one another be not the efficient cause of the emotion, we shall still regard the first--named object with love or hate.

Q.E.D.
PROP.XVII.

If we conceive that a thing, which is wont to affect us painfully, has any point of resemblance with another thing which is wont to affect us with an equally strong emotion of pleasure, we shall hate the first--named thing, and at the same time we shall love it.
Proof .-- The given thing is (by hypothesis) in itself a cause of pain, and (III.xiii.

note), in so far as we imagine it with this emotion, we shall hate it: further, inasmuch as we conceive that it has some point of resemblance to something else, which is wont to affect us with an equally strong emotion of pleasure, we shall with an equally strong impulse of pleasure love it (III.