For motion to cease on its own would require motion to move toward its opposite (rest) by its own nature.

Foremost among the achievements of Descartes’ physics are the three laws of nature (which, essentially, are laws of bodily motion). Newton’s own laws of motion would be modeled on this Cartesian breakthrough, as is readily apparent in Descartes’ first two laws of nature: the first states “that each thing, as far as is in its power, always remains in the same state; and that consequently, when it is once moved, it always continues to move” (Pr II 37), while the second holds that “all movement is,