E4P25D
Demonstration — Part IV
Latin
Conatus quo unaquæque res in suo esse perseverare conatur, sola ipsius rei essentia definitur (per propositionem 7 partis III) eaque sola data, non autem ex alterius rei essentia necessario sequitur (per propositionem 6 partis III) ut unusquisque suum esse conservare conetur. Patet præterea hæc propositio ex corollario propositionis 22 hujus partis. Nam si homo alterius rei causa suum esse conservare conaretur, tum res illa primum esset virtutis fundamentum (ut per se notum) quod (per prædictum corollarium) est absurdum. Ergo nemo suum esse etc. Q.E.D.
English (Elwes 1883)
The endeavour, wherewith everything endeavours to persist in its being, is defined solely by the essence of the thing itself (III. vii.); from this alone, and not from the essence of anything else, it necessarily follows (III. vi.) that everyone endeavours to preserve his being. Moreover, this proposition is plain from IV. xxii. Coroll., for if a man should endeavour to preserve his being for the sake of anything else, the last--named thing would obviously be the basis of virtue, which, by the foregoing corollary, is absurd. Therefore no one, &c. Q.E.D.
Modern English
The *conatus* by which each thing strives to persist in its being is defined by the essence of that thing alone (E3P7), and from that essence alone — not from the essence of anything else — it necessarily follows (E3P6) that each thing strives to preserve its being. This proposition is also plain from the Corollary to P22 of this Part (E4P22C). For if a person were to strive to preserve their being for the sake of something else, that thing would then be the first foundation of virtue (as is self-evident), which (by the said corollary) is absurd. Therefore no one, etc. Q.E.D.