In an essay published recently on National Review Online, John Derbyshire has declared that the documentary Expelled contains a blood libel against Western Civilization. His is an exercise of striking vulgarity, the more so since, as he insouciantly admits, he has not “seen the dang thing.†A blood libel, one might recall, refers to the charge that the Jewish people are irredeemably stained by their occasional, if modest, need for Christian blood. Some terms have acquired through their historical associations a degree of repugnance that persuades sensitive men and women not to use them. If Derbyshire has been repelled by...