Stupid or absurd behavior can be almost laughable at times. That's the kind of situation depicted in an 1871 London Daily News article, describing how a witness "stultified himself" by admitting that he was too far off to hear what he had claimed to have heard. But there is nothing especially funny about the now-archaic original usage of stultify. The word was first used in the mid-1700s in legal contexts, where if you stultified yourself, you claimed to be of unsound mind and thus not responsible for your acts. Nor is there humor in the most common meaning of stultify nowadays, that of rendering someone or something useless or ineffective.