Propositions 15 to 24

15. Anything can, accidentally, be the cause of pleasure, pain, or desire.

Proof= Let it be granted that the mind is simultaneously affected by two emotions, of which one neither increases nor diminishes its power of activity, and the other does either increase or reduce the said power (3. Post. 1).

Corollary= Simply from the fact that we have regarded a thing with the emotion of pleasure or pain, though that thing be not the efficient cause of the emotion, we can either love or hate it.

16. Simply from the fact that we conceive, that a given object has some point of resemblance with another object which is used to affect the mind pleasurably or painfully, although the point of resemblance be not the efficient cause of the said emotions, we shall still regard the first-named object with love or hate.

17. 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.

18. A man is as much affected pleasurably or painfully by the image of a thing past or future as by the image of a thing present.

19. 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.

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

21. He who conceives, that the object of his love is affected pleasurably or painfully, will himself be affected pleasurably or painfully. 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.

22. If we conceive that anything pleasurably affects some object of our love, we shall be affected with love towards that thing. Contrariwise, if we conceive that it affects an object of our love painfully, we shall be affected with hatred towards it.

23. He who conceives, that an object of his hatred is painfully affected, will feel pleasure. Contrariwise, if he thinks that the said object is pleasurably affected, he will feel pain. Each of these emotions will be greater or less, according as its contrary is greater or less in the object of hatred.

24. If we conceive that anyone pleasurably affects an object of our hate, we shall feel hatred towards him also. If we conceive that he painfully affects that said object, we shall feel love towards him.

Proof= This proposition is proved in the same way as III. xxii., which see. Note= These and similar emotions of hatred are attributable to envy, which, accordingly, is nothing else but hatred, in so far as it is regarded as disposing a man to rejoice in another’s hurt, and to grieve at another’s advantage.