Could God have created a better universe? Well, the fundamental scientific laws and parameters of the universe have to be within a certain miniscule range, for a life-sustaining universe to develop: the universe must be 'Fine Tuned'. Therefore the 'embryonic universe' that came into existence with the 'big bang' had to be either exactly as it was or within a certain tiny range, for there to develop a life-sustaining universe. If it is better that there exist a life-sustaining universe than not, then it was better that the embryonic universe was one of this small set of very similar embryonic universes than that it was not. Furthermore, there are no firm grounds for claiming that of this small set of very similar embryonic universes, there is one which would have developed into a universe better than ours. Therefore there are no firm grounds for claiming that God could have created a better universe than ours.
