“The terms ‘more’ or ‘less’ only make sense if something is the maximum in a genus.”
~St. Thomas Aquinas
Consider the argument I developed here to demonstrate the inconceivability and incoherence of there being a ‘best of all possible worlds’. Now, consider that without a standard against which we can speak, gradations of value seem to make no sense. In order to speak as though some things are good and some things evil one needs a standard of goodness which grounds all such language. Therefore, without any best of all possible worlds, is it logically possible to make the claim meaningful that there are some worlds which are better than others (I am presuming the incoherence of the worst of all possible worlds as well, tacitly)?
If there is no best of all possible worlds, then it seems there is no standard against which God could have sufficient reason to prefer some world to another, especially given that gratuitous evil is not logically possible on the supposition of Theism, as I argued here and here. The problem is, of course, that we still feel strongly that a world in which Sally does not intentionally cause a Nuclear holocaust, is better than a world in which she does. What sense can we make of this?
Let me use an analogy from a thought experiment I thought up on the measure of size. Is it logically possible that all objects in the world to whom the concept of size is applicable simultaneously and instantaneously become thrice their original size? It seems as though this is not logically possible, since as far as all appearances are concerned, nothing has changed. I am still twice the size of somebody who was half my size before the supposed change. In fact, there is no way to point to anything in the world which has changed. The only interpretation of this thought experiment which would make it possible that all objects in some world could become thrice their original size would be an interpretation on which size is an objective feature of the world, for which one would need material atoms. Now, not only do material atoms (not to be confused with what physicists call atoms, since they thought it was a real atom when it was first found) not exist apparently, but Leibniz long ago demonstrated that the idea of a material atom may be completely incoherent. To come back to our thought experiment, then, we might say that all objects in the world becoming thrice their previous size, with the exception of one, would be logically possible, since that to which we have given expression is conceivable on the view that size is relative (and I believe without material atoms it must be, regardless of whatever else it might be). However, in that case, we should rather prefer to speak about the one object as having changed size, since our explanation will be simpler or tidier.
In this same way we can speak about one world being preferable to another, and maybe even preferable to God. However, there is no way to speak about one world being better in the sense of being a closer approximation to the best of all possible worlds, or worse in just the opposite sense; namely of approximating more entirely to the worst of all possible worlds.
Thus, from the arguments establishing the incoherence of the notions of best or worst possible worlds, it seems to follow that no world is actually better than another instead of merely preferable. Thus, all logically possible worlds actualize the glory of God satisfactorily. The implications for Theodicy here are, I think, worth exploring.