Which quality or attribute does Mr. Shiftlet claim to have in "The Life You Save May Be Your Own"?

In Flannery O'Connor's "The Life You Save May Be Your Own," Mr. Shiftlet approaches the old woman and Lucynell. After a brief conversation, the following occurs.

"I got," he said, tapping his knuckles on the floor to emphasize the immensity of what he was going to say, "a moral intelligence!" 

The old woman is not impressed with his claim and allows him to sleep in a defunct car on her property while developing her own agenda. 
Shiftlet's claim is ambiguous and laced with irony. The old woman is obviously trying to bribe him into taking on her handicapped daughter, and he recognizes her scheme. She is essentially selling Lucynell to him, and he sees the immorality of her offer—but it doesn't offend him because he is trying to work his own deal. His obvious lack of "moral intelligence" propels him to agree to marry Lucynell in exchange for the car and a small sum of money. Both Shiftlet and the old woman are sorely lacking in moral intelligence, as shown by their ruthless actions with regard to Lucynell.