E2P13D5
Demonstration — Part II
Latin
Corpora enim (per lemma 1) ratione substantiæ non distinguuntur; id autem quod formam individui constituit, in corporum unione (per definitionem præcedentem) consistit; atqui hæc (per hypothesin) tametsi corporum continua fiat mutatio, retinetur : retinebit ergo individuum tam ratione substantiæ quam modi suam naturam uti ante. Q.E.D.
English (Elwes 1883)
Bodies (Lemma i.) are not distinguished in respect of substance: that which constitutes the actuality (formam) of an individual consists (by the last Def.) in a union of bodies; but this union, although there is a continual change of bodies, will (by our hypothesis) be maintained; the individual, therefore, will retain its nature as before, both in respect of substance and in respect of mode. Q.E.D.
Modern English
Bodies are not distinguished with respect to substance (E2L1). What constitutes the form of an individual consists in the union of bodies (E2D8). And this union, even as the bodies change, is retained by hypothesis. The individual will therefore retain its nature as before, with respect to both substance and mode. Q.E.D.