E4P20D
Demonstration — Part IV
Latin
Virtus est ipsa humana potentia quæ sola hominis essentia definitur (per definitionem 8 hujus) hoc est (per propositionem 7 partis III) quæ solo conatu quo homo in suo esse perseverare conatur, definitur. Quo ergo unusquisque magis suum esse conservare conatur et potest eo magis virtute præditus est et consequenter (per propositiones 4 et 6 partis III) quatenus aliquis suum esse conservare negligit eatenus est impotens. Q.E.D.
English (Elwes 1883)
Virtue is human power, which is defined solely by man's essence (IV. Def. viii.), that is, which is defined solely by the endeavour made by man to persist in his own being. Wherefore, the more a man endeavours, and is able to preserve his own being, the more is he endowed with virtue, and, consequently (III. iv. and vi.), in so far as a man neglects to preserve his own being, he is wanting in power. Q.E.D.
Modern English
Virtue is human power itself, defined solely by the human essence (E4D8), that is, (E3P7), defined solely by the *conatus* by which a human being strives to persist in his being. The more each person therefore strives and is able to preserve his being, the more he is endowed with virtue. Consequently (E3P4), insofar as anyone neglects to preserve his own being, to that extent he is powerless. Q.E.D.