The Skepticism of Shakespeare

Shakespeare often suggests that no precepts of moral philosophy, indeed no reasons at all, can explain his character's behavior. Such tragic characters as Hamlet and Macbeth lack self-knowledge and perversely refuse to acquire it. It's a Shakespearean insight that we are just as much, if not more, driven by self-delusion, as by rational analysis of our own motives or the motivations of others. This is encapsulated in a wonderful line from Sonnet 138: When my love swears that she is made of truth, I do believe her, though I know she lies.