The past few years have seen numerous discoveries by cognitive scientists, evolutionary biologists, and even economists who purport to explain how and why we make moral judgments. Interesting, that—seeing as ethics used to be the exclusive realm of philosophers such as Princeton professor Kwame Anthony Appiah. So, how does philosophy deal with the intrusion of science on its turf? Are the findings of researchers a threat to our long-held understanding of what constitutes ethical behavior? Should science be kept far away from understandings of morality? In Experiments in Ethics, Appiah has taken it on himself to figure out how to reconcile the two, and he proves to be a Bill Clinton among thinkers, finding a third way. His verdict: “Experimental philosophy” as it exists today isn’t so far removed from the projects of thinkers decades or even centuries before. Appiah discusses and signs copies of his work at 7 p.m. at Politics and Prose, 5015 Connecticut Ave. NW. Free. (202) 364-1919.