In a short post few months ago, Bill Vallicella argued that “If God exists, and one is an atheist, then one is ignorant of God, but it does not follow that one is culpably ignorant.” (Italics added.)
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.”

Since the 
A Catholic Challenge to Modern Atheism is the subtitle of 

The Apostle Paul speaks of “gnosis falsely so called” (1 Timothy 6:20). Why not also “philosophy falsely so called”? How would that differ from philosophy according to the elements of this world? (Colossians 2:8)
Even if self-identifying “philosophers” disagree about proffered solutions, they would all agree (if asked) that such diversity, what Nicholas Rescher called the
Bill Vallicella, the 