A simple way to explain the argument from efficient causes for the existence of god according to Aquinas? [closed]

Question

According to Aquinas but not originally, I'm not exactly sure whose theory it was that Aquinas reworded.

Answer 1

From https://philosophy.lander.edu/intro/cause.shtml :

1. There is an efficient cause for everything; nothing can be the efficient cause of itself.
2. It is not possible to regress to infinity in efficient causes.
3. To take away the cause is to take away the effect.
4. If there be no first cause then there will be no others.
5. Therefore, a First Cause exists (and this is God).

Premise 1 is unjustified and also inconsistent with there being a First Cause, because a First Cause by definition would not be caused by anything else.

Premise 2 is unjustified.

Premise 3 is the fallacy of denying the antecedent. From Cause -> Effect it is fallacious to conclude ~Cause -> ~Effect. For example, suppose an executioner caused a prisoner's death. From this we cannot conclude that had that executioner not been there, the prisoner would not have died; another executioner could have done the job instead.

Edit: Here's an alternative presentation of it that makes a bit more sense. From https://www3.nd.edu/~jspeaks/courses/mcgill/201/aquinas-cosmological-argument.html

1. Everything which has come to exist has been caused to come to exist.
2. Nothing which has come to exist can be the cause of its own existence.
3. Everything which has come to exist is caused to exist by something other than itself. (follows from 1,2)
4. It is impossible for a chain of causes of this kind to go on to infinity.
5. There must be a first cause, which causes other things to come into existence but did not itself come into existence. (follows from 3,4)

The conclusion 5 would almost follow from the (unjustified) premises, if we interpret premise 2 to rule out causal cycles of any size (time flowing in a circle). However, more than one first cause (a thing that did not itself come into existence but causes other things to do so) are also possible from these premises.