Where do moral rules come from? From reason, some philoso­phers say. From God, say believers. Seldom consid­ered is a source now being advo­cated by some biol­o­gists, that of evolu­tion, says Jonathan Haidt, a moral psychol­o­gist at the Univer­sity of Virginia. · Go to Is Do Unto Others Written Into Our Genes? →