pleasure, arising from the image of something future or past, whereof we do not yet know the issue. Fear, on the other hand, is an inconstant pain also arising from the image of something concerning which we are in doubt. If the element of doubt be removed from these emotions, hope becomes Confidence and fear becomes Despair. In other words, Pleasure or Pain arising from the image of something concerning which we have hoped or feared. Again, Joy is Pleasure arising from the image of something past whereof we have doubted the issue. Disappointment is the Pain opposed to Joy.
PROP. XIX. He who 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