Pastor Stephen Feinstein asserts that without the Christian God, intelligibility is not possible, thus atheism is impossible. By this last phrase, I believe he means that the lack of belief in a personal god - atheism - cannot be true. His words:
In a nutshell, Feinstein's argument reduces to an unsupported assertion that the Christian God exists.
I affirm that the Christian worldview is the only worldview that is possible given the preconditions of intelligibility
My summary - which draws on my own thoughts as well as Duncan's - is this:
Reality must present itself in a way that's capable of being comprehended by hypothetical observers if it is to be understood - it must be "self-consistent". Its features, their attributes, behaviors and relationships must be repeatable under repeatable conditions in order to be understood. From observations that we actual observers make, we can then make inferences about their attributes, behaviors and relationships that might pertain under varying conditions. From those inferences, we then can derive fundamental conventions ("laws" or "axioms") upon which other knowledge items are constructed. Introducing unobserved features into this framework makes the framework inconsistent and thus unintelligible. A god is just such an unobserved feature.
A god or other unobservable feature is not logically ruled out in this scheme, but is instead made unnecessary due to the principle of parsimony ("Occam's Razor"). All other things being equal, the simpler scheme is to be preferred.
It's that simple.