The world is like a child's hoop; when a blow is given to it, it runs on and on; when the force of the blow is spent it stops and falls down, and this may be seen in a lesser way in all things in the world. When the activity of the world has expired the world will fall down. The course of destruction is like the course of manifestation: it is in cycles. The first action is created by the blow given, and each action afterwards causes a further action.