Suppose I agree with theists that "God exists" is a necessary proposition, and so is either a tautology or contradiction. That seems to indicate that the probability of "God exists" is either 1 or 0. Suppose also that I don't know which it is, but I find the evidential argument from evil convincing, and so rate the probability of "God exists" at, say, 0.2. But if the probability of "God exists" is either 1 or 0, then it can't be 0.2 - that would be like saying that "God exists" is a contingent proposition, which I've accepted it isn't. How then can I apply probabilistic reasoning to "God exists" at all? If I can, then how should I explain the apparent conflict?