E5P29D
Demonstration — Part V
Latin
Quatenus mens præsentem sui corporis existentiam concipit eatenus durationem concipit quæ tempore determinari potest et eatenus tantum potentiam habet concipiendi res cum relatione ad tempus (per propositionem 21 hujus et propositionem 26 partis II). At æternitas per durationem explicari nequit (per definitionem 8 partis I et ipsius explicationem). Ergo mens eatenus potestatem non habet concipiendi res sub specie æternitatis sed quia de natura rationis est res sub specie æternitatis concipere (per II corollarium propositionis 44 partis II) et ad mentis naturam etiam pertinet corporis essentiam sub specie æternitatis concipere (per propositionem 23 hujus) et præter hæc duo nihil aliud ad mentis essentiam pertinet (per propositionem 13 partis II) ergo hæc potentia concipiendi res sub specie æternitatis ad mentem non pertinet nisi quatenus corporis essentiam sub specie æternitatis concipit. Q.E.D.
English (Elwes 1883)
In so far as the mind conceives the present existence of its body, it to that extent conceives duration which can be determined by time, and to that extent only has it the power of conceiving things in relation to time (V. xxi. II. xxvi.). But eternity cannot be explained in terms of duration (I. Def. viii. and explanation). Therefore to this extent the mind has not the power of conceiving things under the form of eternity, but it possesses such power, because it is of the nature of reason to conceive things under the form of eternity (II. xliv. Coroll. ii.), and also because it is of the nature of the mind to conceive the essence of the body under the form of eternity (V. xxiii.), for besides these two there is nothing which belongs to the essence of mind (II. xiii.). Therefore this power of conceiving things under the form of eternity only belongs to the mind in virtue of the mind's conceiving the essence of the body under the form of eternity. Q.E.D.
Modern English
Insofar as the mind conceives the present existence of its body, it conceives a duration that can be determined by time, and only to that extent does it have the power to conceive things in relation to time (E5P21). But eternity cannot be explained through duration (E1D8). Therefore the mind has no power, to that extent, to conceive things *sub specie aeternitatis*.
Yet because it belongs to the nature of reason to conceive things *sub specie aeternitatis* (E2P44C2), and because it also belongs to the nature of the mind to conceive the body's essence *sub specie aeternitatis* (E5P23), and because beyond these two nothing else belongs to the essence of the mind (E2P13), this power of conceiving things *sub specie aeternitatis* belongs to the mind only insofar as it conceives the body's essence *sub specie aeternitatis*. Q.E.D.