E4P50D
Demonstration — Part IV
Latin
Commiseratio enim (per 18 affectuum definitionem) tristitia est ac proinde (per propositionem 41 hujus) per se mala; bonum autem quod ex ea sequitur, quod scilicet hominem cujus nos miseret, a miseria liberare conamur (per corollarium III propositionis 27 partis III) ex solo rationis dictamine facere cupimus (per propositionem 37 hujus) nec nisi ex solo rationis dictamine aliquid quod certo scimus bonum esse, agere possumus (per propositionem 27 hujus) atque adeo commiseratio in homine qui ex ductu rationis vivit, per se mala est et inutilis. Q.E.D.
English (Elwes 1883)
Pity (Def. of the Emotions, xviii.) is a pain, and therefore (IV. xli.) is in itself bad. The good effect which follows, namely, our endeavour to free the object of our pity from misery, is an action which we desire to do solely at the dictation of reason (IV. xxxvii.); only at the dictation of reason are we able to perform any action, which we know for certain to be good (IV. xxvii.); thus, in a man who lives under the guidance of reason, pity in itself is useless and bad. Q.E.D.
Modern English
Compassion is sadness (E3DA18), and is therefore bad in itself (E4P41). The good that follows from it — namely, our striving to free the person we feel compassion for from misery (E3P27C3) — is something we want to do from reason's dictate alone (E4P37). And we can only perform an action that we know with certainty to be good from reason's dictate (E4P27). Therefore compassion in a person who lives under the guidance of reason is bad and useless in itself. Q.E.D.