Our second attempt to measure dogmatic behavior involved simply asking the San Francisco atheists [n = 253] the question, "What would be required, what would have to happen, for you to believe in the 'traditional' God described at the beginning of this survey? Are there conceivable events, or evidence, that would lead you to believe? What, for example?"
We got many different answers to this open-ended question. ... Nevertheless, 51 percent of the Bay Area atheists said there was nothing conceivable that could change their minds on the existence of the traditional God.
We found this level of closed-mindedness hard to believe, and suspected the wording of our question had not communicated our intention. So we reworked the item for the Alabama/Idaho sample, to make sure the informants knew we would take anything they would consider a test of the matter. Specifically, we inserted, "Is there absolutely nothing that could happen that would convince you? Or are there conceivable events—however unlikely or unprecedented—that would lead you to believe? What?" And 52 percent of the Alabama/Idaho atheists still said nothing would change their minds. Nothing. And the thirty-eight Manitoba parent atheists who encountered this question (in its original wording) were even more locked down, with 57 percent choosing the response, "No, there's nothing."
All of which implies that if the traditional God does exist, an awful lot of atheists are going to miss out on the fact no matter what happens.
--Bruce Hunsberger and Bob Altemeyer, Atheists: A Groundbreaking Study of America's Nonbelievers, on unshakable unbelief
We asked forty-five highly fundamentalist parents, "What would be required, what would have to happen, for you to not believe in the traditional Judeo-Christian God? That is, are there conceivable events, or evidence, that would lead you to not believe?" All of them said nothing could do this.
--Hunsberger and Altemeyer on belief at the other end of the spectrum