2p13l3d.md (514B)
1 Bodies are individual things (II., Def. i.), which (Lemma I.) are distinguished 2 one from the other in respect to motion and rest; thus (I. xxviii.) each must 3 necessarily be determined to motion or rest by another individual thing, namely 4 (II. vi.), by another body, which other body is also (Ax. i.) in motion or at 5 rest. And this body again can only have been set in motion or caused to rest by 6 being determined by a third body to motion or rest. This third body again by a 7 fourth, and so on to infinity. Q.E.D. 8 9