Now, in a series of per se ordered causes, every cause lower in the chain depends for its causal efficacy on what is higher. So much is this the case that if the higher cause does not cause, the lower cause does cause. To describe this fact, we can call each of the causes that itself depends an “instrumental” cause.
We have drawn our definitions. Now, here is the argument. If there is no non-instrumental cause, then no instrument can act. That is, there must be a non-instrumental cause. There must be a cause that is not itself dependent on a higher cause. If there is no non-instrumental cause, then it would be impossible for any instrumental cause to have its instrumental agency. Just as if my arm were not moving, neither could my hand be moving. If the shaft were not moving, neither could the plunger be moving.
(Even if you allow the per se ordered series to be infinite, there has to be one cause outside that infinite series that is itself not moved, not caused, not instrumental. An instrument works only in virtue of an agent. The whole series of instruments is as “one instrument” in relation to the ultimate agent. No agent, no instrument!)
So, if every single cause were simply an instrumental cause, then there would be no non-instrumental cause. And thus there would be no instrumental agency.
But it is obvious, when we look around, that there is instrumental agency. For the sun moves the flowers to grow, and the wind draws the boat forward, and I am communicating to you.
Therefore, we must come to a first cause that is a non-instrumental cause. And this, all (or at least many) call God.
Part 15 and this part amount to a refutation of the claim of these Mormons, revealed by some “prophet” in the 20th century, that God the Father himself was a man like you or I who evolved into his deity. Thus, reason itself demonstrates the falsity of their claim.