Again, we have no way of knowing what was in Gray’s mind when he plotted the murder of his lover’s husband. But if Gray really wasn’t a sociopath, and possessed a capacity and willingness for rational and principled thinking—this is what he would have done. His evasion of this logic, and his subsequent participation in the murder, certainly reaffirms that he deserved whatever exposure and punishment came next.

Notice how the antidote to all-or-nothing thinking, especially in Gray’s example, is actually principled thinking. If Mencken is right, and Gray failed to make a rational distinction between bad judgment (i.e., having an affair) and outright evil (i.e., carrying out a murder), then how could Gray have done differently? By recognizing the principle that the initiation of force—murder being an obvious example—is absolutely and always wrong. Nothing justifies it: Not the wife’s desire to achieve financial independence and escape from an unhappy marriage, and surely not his own desire to escape guilt feelings over a far lesser sin or crime than the one he ultimately committed.

This melodrama has implications for the seemingly more mundane tasks of the cognitive therapist and his or her client in psychotherapy. All-or-nothing thinking is irrational because it involves a breakdown in logical thinking, by means of a failure to recognize or appreciate rational distinctions. Ironically, attention to principle is part of the solution. A person depressed over his failure to exercise every single day can think, “That’s it. I blew it. I didn’t exercise today. That ruins the whole thing. I might as well stop.” Or, he can take this approach: “I blew it. But I’ll just redouble my resolve for tomorrow, and the next day. The absolute imperative here is health.” Notice how attention to an absolute helps break the depressing cycle—and even the rationalization for inaction—that lurks behind the all-or-nothing thinking.

People who are mentally unwell suffer from both a failure to make rational distinctions—and a failure to appreciate absolutes.

Source of Mencken article: “A Mencken Chrestomathy: His Own Selection of his Choicest Writings,” edited and annotated by H.L. Mencken. New York: Vintage Books, republished 1982.