The question refers to the character of Joy-Hulga from Flannery O'Connor's short story "Good Country People." The question is one with which O'Connor herself must have struggled because she was a highly educated person, but at the same time a person with an active Christian faith.
In the short story, Joy-Hulga is also a highly educated person, but, unlike O'Connor, Joy-Hulga has a negative view of the Christian faith. This manifests itself in the contempt with which she holds the Bible salesman (Manley Pointer), who arrives at her house.
Joy-Hulga's attitude that intelligence and education are incompatible with religious faith, namely the Christian religious tradition, is a fairly common view. The Christian faith requires a belief in concepts such as virgin birth, a divine being walking the earth in human form, and resurrection from the dead. These are miracles that people of intelligence and education have a difficult time rationalizing.
Thus, it is not surprising that Joy-Hulga, as a college-educated person, holds such a view. For a woman in the southern part of the United States in the 1950s, when "Good Country People" was written, to hold such a view strikes me as quite rare for that time. As more and more people experience a liberal arts education, though, we will find such an attitude more and more common.
O'Connor shows Hulga to be limited and blinded by her view that intelligence and education are incompatible with religious faith. Her belief in her own intelligence is a form of pride and arrogance that prevents her from seeing what is in front of her, most notably the existence of evil in the world, especially in Pointer. She persists in feeling superior to him and takes his assertions of his faith at face value. She, like her mother, can't imagine that he is lying: in fact, for all her claims of atheism, she has more of faith sensibility than Pointer. She has faith that people are basically decent and this allows her to trust this utterly cynical, faithless bible salesman. She projects her own desires and her religious sensibility (which she would consciously deny having) onto him, imagining him feeling "remorse" and "shame" after she seduces him. She thinks as follows:
During the night she had imagined that she seduced him. She imagined that the two of them walked on the place until they came to the storage barn beyond the two back fields and there, she imagined, that things came to such a pass that she very easily seduced him and that then, of course, she had to reckon with his remorse. True genius can get an idea across even to an inferior mind. She imagined that she took his remorse in hand and changed it into a deeper understanding of life. She took all his shame away and turned it into something useful.
Of course, Pointer is utterly without any feelings of remorse or shame. It is Hulga who, despite all her education, has the "inferior" mind. She is the one who will need to take her shame and remorse and turn them into something useful. If she had been less blinded by her philosophy PhD, she might have been more humble and had an inkling of what Pointer really was. As he says to her: "You ain't so smart."