Then this Prana is said to sleep for a period, again to emerge and to throw out all those forms; and when this period will end, the whole thing will subside again. Thus this process of creation is going down, and coming up, oscillating backwards and forwards. In the language of modern science, it is becoming static during one period, and during another period it is becoming dynamic. At one time it becomes potential, and at the next period it becomes active. This alteration has gone on through eternity.