2p13l3c.md (1098B)
1 Hence it follows, that a body in motion keeps in motion, until it is determined 2 to a state of rest by some other body; and a body at rest remains so, until it 3 is determined to a state of motion by some other body. This is indeed 4 self–evident. For when I suppose, for instance, that a given body, A, is at 5 rest, and do not take into consideration other bodies in motion, I cannot affirm 6 anything concerning the body A, except that it is at rest. If it afterwards 7 comes to pass that A is in motion, this cannot have resulted from its having 8 been at rest, for no other consequence could have been involved than its 9 remaining at rest. If, on the other hand, A be given in motion, we shall, so 10 long as we only consider A, be unable to affirm anything concerning it, except 11 that it is in motion. If A is subsequently found to be at rest, this rest cannot 12 be the result of A's previous motion, for such motion can only have led to 13 continued motion; the state of rest therefore must have resulted from something, 14 which was not in A, namely, from an external cause determining A to a state of 15 rest. 16 17