Main premise of the argument
- Efficient causes come in series, and we do not and cannot find something is its own efficient cause
- If something were its own efficient cause, it would be prior to itself, which is impossible
- The series of efficient causes cannot go back to infinity
- A first thing causes one or more intermediaries, and the intermediaries cause the last thing, so when a cause is taken out of this series, so is it’s effect, so there has to be a first efficient cause, which we understand to be God
Exegesis
There was an act of creation, and if we go back in time we will eventually arrive at this act
First objection
There can be causal overdetermination - something can still happen even if you take away a cause, as there could be other causes
Second objection
Aquinas commits the quantifier switch fallacy - he dogmatically rules out the possibility that events could extend infinitely far back into the past. Each event could be caused by an earlier event while no event is initial in the sense of temporal ordering
Third objection
Even in the big bang model, there is no first cause. The big bang is not actually an event in time, it is outside of space time. It is like the number 0 in the sense that you could go infinitely far back from it and infinitely forward.
Also, if you are making time hops that get slightly smaller each time, you would not actually ever reach the first cause
Fourth objection
If there were a first efficient cause, why should we believe it was God