"Thus in a sense movement has two aspects. On one hand, that which happens between objects or parts; on the other hand that, which expresses the duration or the whole. The result is that duration, by changing qualitatively, is divided up in objects, and objects, by gaining depth, by losing their contours, are united in duration. We can therefore say that movement relates the objects of a closed system to open duration, and duration to the objects of the system which it forces to open up.