Bill takes his definition of “culpable ignorance” from a Catholic dictionary: ignorance is blameworthy if the ignorant one could have “cleared up” his ignorance, but chose not to. “One is said to be simply (but culpably) ignorant,” the dictionary says, “if one fails to make enough effort to learn what should be known.”
Bill applies this to the atheist this way:
I hold that there is vincible ignorance on various matters. But I deny that atheists are vincibly ignorant. Some might be, but not qua atheists. Whether or not God exists, one is not morally culpable for denying the existence of God. Nor do I think one is morally culpable if one doubts the existence of God.
Bill acknowledges that his exculpation of the professing atheist “puts me at odds with St. Paul, at least on one interpretation of what he is saying at Romans 1: 18-20.”
I’ll say! As Bill wrote in the post he linked to: “There are sincere and decent atheists, and they have plenty of excuse for their unbelief. The best of them, if wrong in the end, are excusably wrong.”