o conceives that the object of his love is
destroyed will feel pain; if he conceives that it is preserved
he will feel pleasure.

Proof.--The mind, as far as possible, endeavours to conceive
those things which increase or help the body's power of activity
(III. xii.); in other words (III. xii. note), those things which
it loves. But conception is helped by those things which
postulate the existence of a thing, and contrariwise is hindered
by those which exclude the existence of a thing (II. xvii.);
therefore the images of things, which postulate the existence of
an object of love, help the mind's endeavour to conceive the
object of love, in other words (III. xi. note), affect the mind
pleasurably; contrariwise those things, which exclude the
existence of an object of love, hinder the aforesaid mental
endeavour; in other words, affect the mind painfully. He,
therefore, who conceives that the object of his love is destroyed
will feel pain, &c. Q.E.D.

PROP. XX. He who conceives that the object of his hate is
destroyed will also feel pleasure.

Proof.--The mind (III. xiii.) endeavours to conceive those
things, which exclude the existence of things whereby the body's
power of activity is diminished or constrained; that is (III.
xiii. note), it endeavours to conceive such things as exclude the
existence of what it hates; therefore the image of a thing,
which excludes the existence of what the mind hates, helps the
aforesaid mental effort, in other words (III. xi. note), affects
the mind pleasurably. Thus he who conceives that the object of
his hate is destroyed will feel pleasure. Q.E.D.

PROP. XXI. He who conceives, that the object of his love is
affected pleasurably or painfully, will himself be affected
pleasurably or painfully; and the one or the other emotion will
be greater or less in the lover according as it is greater or
less in the thing loved.

Proof.--The images of things (as we showed in III. xix.) which
postulate the existence of the object of love, help the mind's
endeavour to conceive the said object. But pleasure postulates
the existence of something feeling pleasure, so much the more in
proportion as the emotion of pleasure is greater; for it is
(III. xi. note) a transition to a greater perfection; therefore
the image of pleasure in the object of love helps the mental
endeavour of the lover; that is, it affects the lover
pleasurably, and so much the more, in proportion as this emotion
may