Three-Minute Mysteries for Epistemologists

The local constabulary was stumped. Moments before the party was to have begun, Colonel Maynard had been found with a stab wound in his back. He lay in front of the buffet table, which held a large ice sculpture of a heron, although its long, sharp beak had been broken off and was missing. No murder weapon could be found, although a still-warm hairdryer was discovered plugged into a nearby electric outlet. The chief inspector was about to write the death off to natural causes, when Professor Harris, head of the local university's philosophy department, broke in. "There are your murderers, Chief!" the professor exclaimed, pointing at the caterer and the hairstylist. "Arrest those men!"

HOW DID THE PROFESSOR KNOW?


Answer: First, the professor believed that the caterer and hairstylist were the perpetrators. Second, it was in fact true that they had murdered the colonel. Third, the professor's belief was justified—that is, it was caused in a reliable way, given the circumstances, having been the only possible conclusion of a process of deductive reasoning that took the physical evidence of the crime as its starting premises. The generally agreed-upon definition of knowledge is that it consists of justified, true belief. Thus, since Professor Harris had a belief concerning the identity of the murders that was both justified and true, he can say that he "knew" this.