What I want to know is how do you get "cannot?" What is it that we now know that we can say that God (and again with the arbitrary definition problem already brought up in this thread) cannot exist? What rules forbid it?
Given that the supernatural model of the universe has been thoroughly debunked, having lost every possible contest, and the naturalistic model has replaced it at every point....
God can be said to interact with our universe or not.
If not, then it cannot be said, in any meaningful way, to exist.
If so, then it either contradicts purely physical laws, or it does not.
If it does, then it is contrary to observed fact, and therefore false.
If it does not, then it is indistinguishable from not-God, and therefore meaningless.
And btw, the arbitrary definition ruse is not a "problem" for the reasons stated above... it is merely a retreat into a non-claim. It's as if the losing team, having lost every point in the match, decided to quit the field, and to claim victory in doing so, on the grounds that no further points may then be scored against them.