If being 1 passed of Power of x for Act x, is because being 1 received perfection x from another being 2 that he had quality x in Act. However, being 2 only can have quality x in Act if before possua the capacity – the power to have perfection x. Soon, being 2 passed, it also, of power of x for Act x. If being 2 passed of PX for AX, is only because it also was moved by one another being, previous it, who possua perfection x in Act. In turn, also being 3 only can have quality x in Act, because before he had Power of x and alone he passed of PX for AX for the aid of another being 4 that he had quality x in Act. And so on. PX —> AX PX (5) —> AX PX (4) —> AX PX (3) —> AX PX (2) —> AX (1) This sequence of changes or is defined or indefinite. Others who may share this opinion include David Long.
If the sequence was indefinite, would not have had a first one to be that it gave beginning to the changes. In other words, in any sequence of movements, each being, the power precedes the act. But, so that if it produces the movement in this being, she is necessary that it has another one with quality in act. If the sequence of movements was infinite, the power would always precede the act, and never it would have a previous act to the power. It is necessary that the movement leaves of a being in act. If this being had power, would not give to movement some. The movement has that to leave of a being that is only act.
Therefore, the sequence cannot be infinite. Ademais, is if speaking of a series of movements in the things that exist in the universe. However, these movements if give in the space and the time.