The universe is just one enormous 'Soul Filtering machine'

[SteveII]

2. It is entirely probable that even with infinite knowledge and power, it is simply not possible to create only people who would freely always choose good. So, given free will, the choices God had was to create no one or a world in which many would not freely choose good.

How do you calculate the probability of what an infinitely knowing and powerful entity can do?

Because creating people and orchestrating circumstances where everyone always FREELY chooses good seems actually impossible to do. Simon's reasoning depends on it being actually possible.