Sentence:  And yet it would seem that the whole analysis he had made, his attempt to find a moral solution to the problem, was complete. His <WSD>casuistry</WSD> had been honed to a razor's edge, and he could no longer think of any objections. 
Meaning of the word marked with <WSD> tags:  The process of answering practical questions via interpretation of rules, or of cases that illustrate such rules, especially in ethics; case-based reasoning.