and pleasure, it follows in like manner that the endeavour, appetite, or desire, which arises through hatred or love, will be greater in proportion to the hatred or love. Q.E.D.
XXXVIII. 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. For love is a pleasure (III. xiii. note) which a man endeavours as far as he can to render permanent (III. xxviii.); he does so by regarding the object of his love as present, and by affecting it as far as he can pleasurably; this endeavour is greater in proportion as the love is greater, and so also is the endeavour to bring about that the beloved should return his affection (III. xxxiii.). Now these endeavours are constrained by hatred towards the object of love (III. xiii. Cor. and III. xxiii.); wherefore the love (III. xi. note) will for this cause also be affected with pain, the more so in proportion as his love has been greater; that is, in addition to the pain caused by hatred, there is a pain caused by the fact that he has loved the object; wherefore the lover will regard the beloved with greater pain, or in other words, will hate it more than if he had never loved it, and with the more intensity in proportion as his former love was greater. Q.E.D.
XXXIX. 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.
Proof--To hate a man is (III. xiii. note) to conceive him as a cause of pain; therefore he who hates a man will endeavour to remove or destroy him. But if anything more painful, or, in other words, a greater evil, should accrue to the hater thereby --and if the hater thinks he can avoid such evil by not carrying out the injury, which he planned against the object of his hatred --he will desire to abstain from inflicting that injury (III. xxviii.), and the strength of his endeavour (III. xxxvii.) will be greater than his former endeavour to do injury, and will therefore prevail over it, as we asserted. The second part of this proof proceeds in the same manner. Wherefore he who hates another, etc. Q.E.D.