Propositions 15 to 24

38. If a man has begun to hate an object of his love, so that love is thoroughly destroyed, he will, causes being equal, regard it with more hatred than if he had never loved it, and his hatred will be in proportion to the strength of his former love. Proof= If a man begins to hate that which he had loved, more of his appetites are put under restraint than if he had never loved it.

39. He who hates anyone will endeavour to do him an injury, unless he fears that a greater injury will thereby accrue to himself; on the other hand, he who loves anyone will, by the same law, seek to benefit him.

40. He, who conceives himself to be hated by another, and believes that he has given him no cause for hatred, will hate that other in return.

Corollary 1= He who conceives, that one whom he loves hates him, will be a prey to conflicting hatred and love. For, in so far as he conceives that he is an object of hatred, he is determined to hate his enemy in return. But, by the hypothesis, he nevertheless loves him= wherefore he will be a prey to conflicting hatred and love.

Corollary 2= If a man conceives that one, whom he has hitherto regarded without emotion, has done him any injury from motives of hatred, he will forthwith seek to repay the injury in kind. Proof= He who conceives, that another hates him, will (by the last proposition) hate his enemy in return, and (3.26) will endeavour to recall everything which can affect him painfully; he will moreover endeavour to do him an injury (3.39). Now the first thing of this sort which he conceives is the injury done to himself; he will, therefore, forthwith endeavour to repay it in kind. Q.E.D. Note= The endeavour to injure one whom we hate is called Anger. The endeavour to repay in kind injury done to ourselves is called Revenge.

41. If anyone conceives that he is loved by another, and believes that he has given no cause for such love, he will love that other in return. (Cf. 3.15 Coroll., and 3.16)

Corollary= He who imagines that he is loved by one whom he hates, will be a prey to conflicting hatred and love. This is proved in the same way as the first corollary of the preceding proposition.

Note= If hatred be the prevailing emotion, he will endeavour to injure him who loves him. This emotion is called cruelty, especially if the victim be believed to have given no ordinary cause for hatred.

42. He who has conferred a benefit on anyone from motives of love or honour will feel pain, if he sees that the benefit is received without gratitude. Proof= When a man loves something similar to himself, he endeavours, as far as he can, to bring it about that he should be loved thereby in return (3.33). Therefore he who has conferred a benefit confers it in obedience to the desire, which he feels of being loved in return; that is (3.34) from the hope of honour or (3.30 note) pleasure. Hence he will endeavour, as far as he can, to conceive this cause of honour, or to regard it as actually existing. But, by the hypothesis, he conceives something else, which excludes the existence of the said cause of honour= Wherefore he will thereat feel pain (3.19). Q.E.D.

43. Hatred is increased by being reciprocated, and can on the other hand be destroyed by love. Proof= He who conceives, that an object of his hatred hates him in return, will thereupon feel a new hatred, while the former hatred (by hypothesis) still remains (3.40). But if, on the other hand, he conceives that the object of hate loves him, he will to this extent (3.38) regard himself with pleasure, and (3.29) will endeavour to please the cause of his emotion. In other words, he will endeavour not to hate him (3.41), and not to affect him painfully; this endeavour (3.37) will be greater or less in proportion to the emotion from which it arises. Therefore, if it be greater than that which arises from hatred, and through which the man endeavours to affect painfully the thing which he hates, it will get the better of it and banish the hatred from his mind. Q.E.D.

44. Hatred which is completely vanquished by love passes into love= and love is thereupon greater than if hatred had not preceded it.

45. If a man conceives, that anyone similar to himself hates anything also similar to himself, which he loves, he will hate that person.

46. If a man has been affected pleasurably or painfully by anyone, of a class or nation different from his own, and if the pleasure or pain has been accompanied by the idea of the said stranger as cause, under the general category of the class or nation= the man will feel love or hatred, not only to the individual stranger, but also to the whole class or nation whereto he belongs.

47. Joy arising from the fact, that anything we hate is destroyed, or suffers other injury, is never unaccompanied by a certain pain in us.

48. Love or hatred towards, for instance, Peter is destroyed, if the pleasure involved in the former, or the pain involved in the latter emotion, be associated with the idea of another cause= and will be diminished in proportion as we conceive Peter not to have been the sole cause of either emotion.

Proof= This Proposition is evident from the mere definition of love and hatred (3.13 note).

For pleasure is called love towards Peter, and pain is called hatred towards Peter, simply in so far as Peter is regarded as the cause of one emotion or the other. When this condition of causality is either wholly or partly removed, the emotion towards Peter also wholly or in part vanishes. Q.E.D.

49. Love or hatred towards a thing, which we conceive to be free, must, other conditions being similar, be greater than if it were felt towards a thing acting by necessity.

50. Anything whatever can be, accidentally, a cause of hope or fear.

51. Different men may be differently affected by the same object, and the same man may be differently affected at different times by the same object.

52. An object which we have formerly seen in conjunction with others, and which we do not conceive to have any property that is not common to many, will not be regarded by us for so long, as an object which we conceive to have some property peculiar to itself.