We have already encountered the argument from particularity, the crux of which is that if no reason can be found for why something is one way rather than another, it must be the product of a free agent or particularizer (mukhaṣṣiṣ) who made the world as we have it. We can understand the force of the argument if we return to Aristotle. According to the Posterior Analytics (71b14–15), the object of scientific knowledge is most properly that which cannot be otherwise. It follows that if there are things in the world that can be otherwise, they will not be subject to scientific understanding. The alternative is to say they can be understood in terms of choice rather than necessity. Once we have a God who exercises choice, we have the basis for asserting creation de novo. In Maimonides' words (GP 1.74, p. 218): “There is no difference between your saying someone who particularizes or who makes or who creates or who brings into existence or who creates in time or who purposes the universe.”

We saw that for Plotinus, there is no possibility of God's being selective: everything that can be produced is produced. Although proponents of emanation can avoid the question of why the world was created at one moment rather than another by claiming that the production in question is eternal, they cannot avoid similar questions in regard to space. Aristotle was supposed to have shown that an actual infinite is impossible.