E4P38D
Demonstration — Part IV
Latin
Quo corpus ad hæc aptius redditur, eo mens aptior ad percipiendum redditur (per propositionem 14 partis II) adeoque id quod corpus hac ratione disponit aptumque ad hæc reddit, est necessario bonum seu utile (per propositiones 26 et 27 hujus) et eo utilius quo corpus ad hæc aptius potest reddere et contra (per eandem propositionem 14 partis II inversam et propositiones 26 et 27 hujus) noxium si corpus ad hæc minus aptum reddat. Q.E.D.
English (Elwes 1883)
Whatsoever thus increases the capabilities of the body increases also the mind's capability of perception (II. xiv.); therefore, whatsoever thus disposes the body and thus renders it capable, is necessarily good or useful (IV. xxvi. xxvii.); and is so in proportion to the extent to which it can render the body capable; contrariwise (II. xiv., IV. xxvi. xxvii.), it is hurtful, if it renders the body in this respect less capable. Q.E.D.
Modern English
The more apt the body is rendered in this respect, the more apt the mind becomes for perception (E2P14). Therefore what disposes the body in this way and makes it apt for these things is necessarily good or useful (E4P26), and the more useful in proportion as it can render the body more apt. Conversely (E2P14)(E4P26), whatever makes the body less apt in this respect is harmful. Q.E.D.