 It is clear how an occasional cause contributes to the motion of a second body in a case where the occasional cause “oppose[s] and over-power[s] another which is inferior to it.” The occasional cause “hinder[s]” the second body and “force[s]” it to move in ways that it otherwise would not. The second body still moves by its own self-motion, for “this hinderance and opposition doth not take away self-motion.” Motion is never transfered from one body to another, and so the motion of a body – and even the motion of a body that is over-powered – is motion that the body has possessed all along. But the occasional cause still redirects the self-motion of the second body; it re-directs the self-motion of the second body, which is to say that it re-directs the motions that the second body already had. Note that Cavendish uses the language of “occasional causes” (for example at Cavendish 1664, 79), but her understanding of occasional causation is not the same as that of 17th-Century contemporaries like Malebranche and Boyle. For Cavendish an occasional cause is something that triggers or occasions motion that is already in (and is inseparable from) the affected body.