E4P28D
Demonstration — Part IV
Latin
Summum quod mens intelligere potest, Deus est hoc est (per definitionem 6 partis I) Ens absolute infinitum et sine quo (per propositionem 15 partis I) nihil esse neque concipi potest adeoque (per propositiones 26 et 27 hujus) summum mentis utile sive (per definitionem 1 hujus) bonum est Dei cognitio. Deinde mens quatenus intelligit eatenus tantum agit (per propositiones 1 et 3 partis III) et eatenus tantum (per propositionem 23 hujus) potest absolute dici quod ex virtute agit. Est igitur mentis absoluta virtus intelligere. At summum quod mens intelligere potest, Deus est (ut jam jam demonstravimus). Ergo mentis summa virtus est Deum intelligere seu cognoscere. Q.E.D.
English (Elwes 1883)
The mind is not capable of understanding anything higher than God, that is (I. Def. vi.), than a Being absolutely infinite, and without which (I. xv.) nothing can either be or be conceived; therefore (IV. xxvi. and xxvii.), the mind's highest utility or (IV. Def. i.) good is the knowledge of God. Again, the mind is active, only in so far as it understands, and only to the same extent can it be said absolutely to act virtuously. The mind's absolute virtue is therefore to understand. Now, as we have already shown, the highest that the mind can understand is God; therefore the highest virtue of the mind is to understand or to know God. Q.E.D.
Modern English
The highest thing the mind can understand is God (E1D6), that is, (by Definition 6 of Part I), a being absolutely infinite, without which (E1P15) nothing can exist or be conceived. Therefore (E4P26) the mind's highest utility, or (E4D1) good, is the knowledge of God.
Next, the mind acts only insofar as it understands (E3P1), and only to that extent can it be said absolutely to act from virtue (E4P23). The mind's absolute virtue is therefore to understand. But the highest thing the mind can understand is God, as just demonstrated. Therefore the mind's highest virtue is to understand, that is, to know, God. Q.E.D.