and thus the existence of a creature before any creature has existed at all would conjoin two mutually exclusive opposites. This is different from saying that He does not bring a particular creature into being until He has brought another particular creature into being; such a sequence is not impossible, just as a child is not begotten from another without the prior existence of its parent.
Once this is clear, the eternalist philosophers’ proof for the world’s pre-eternity rests on two premises. The first is the impossibility of preference without a preferrer, and the second is the impossibility of an infinite regress in the root of causation, though not in any particular causal act. They argue that if the fully sufficient cause existed from eternity, its effect must likewise be eternal; for if the effect were to arise later, this would amount to preference without a preferrer. Conversely, if the fully sufficient cause did not exist from eternity, nothing could arise from it, because the occurrence of any new effect without a new cause would again constitute preference without a preferrer. Yet the arising of a new cause is itself impossible, for the same reasoning applied to the occurrence of the conditioned object applies equally to the occurrence of the conditioning cause. Since, by hypothesis, no fully sufficient cause existed from eternity, the very genus and completion of causation would have to come into being, so that the agent would become an agent after previously not being an agent at all.
This is impossible in itself, as explained earlier, because the very coming-into-being of his agency would require an agent—yet there is no agent but Him. It would therefore follow that He was an agent before He was an agent, which is a contradiction.
Moreover, if He were not a fully sufficient cause and then made Himself such, preference without a preferrer would again ensue; for His making Himself an agent after not being one, while the circumstances are identical, is even more emphatically impossible than His producing an external effect after not producing it, while the circumstances remain identical.