Classical Usage: After receiving the letter from his mother informing him of his sister’s engagement to Pyotr Petrovich Luzhin, Raskolnikov spends most of Chapter IV of Part One railing against the idea. He is sure that Dunya, apparently a smart, strong, independent woman, is making up her own rules of morality for the sake of him and his mother. He can’t stand it. That’s what our whole catch consists of: for her brother, for her mother, she will sell herself! She’ll sell everything! Oh, in that case, given the chance, we’ll even crush our moral feeling . . . So long as these beloved being of ours are happy. Moreover, we’ll invent our own casuistry, we’ll take a lesson from the Jesuits, . . .
Classically Mad Usage: I’m happy to say that I’ve encountered this word before, simply because our good friend, and former pastor, Dr. Ben Mayes, wrote a dissertation titled Counsel and Conscience: Lutheran Casuistry and Moral Reasoning After the Reformation. Okay, so I haven’t actually read anything but the title, but I think I get the drift of it.