 Dorfman poisons Mrs. Dorfman by putting what he takes to be arsenic in her tea. The stuff is indeed arsenic and Mrs. Dorfman dies as planned. But Dorfman does not know that the stuff is arsenic (or that his act subjects his victim to an unjustifiable risk of death) because: The chemist who sold Dorfman the arsenic is a famous liar … [G]iven the chemist’s well-known track record of selling sugar as arsenic to would-be poisoners, Dorfman had no business believing him. Dorfman’s pertinent beliefs are true, but they do not amount to knowledge because they are based on insufficient evidence. (Rosen 2008: 596)