At the age of 87, several years after he had stopped writing, Isaiah Berlin responded to an invitation from a Chinese professor to summarize his ideas for publication in China. He produced an extraordinary essay that defended moral pluralism and warned against its enemy, moral monism (or moral absolutism), which he defined as the thesis that "to all true questions there must be one true answer and one only, all the other answers being false." He then wrote: Most revolutionaries believe, covertly or overtly, that in order to create the ideal world eggs must be broken, otherwise one cannot obtain the omelette. Eggs are certainly broken—never more violently or ubiquitously than in our times—but the omelette is far to seek, it recedes into an infinite distance. That is one of the corollaries of unbridled monism, as I call it—some call it fanaticism, but monism is at the root of every extremism. (Berlin, 1998) In this essay we build upon Berlin's idea 1 and argue that the elevation or "sacralization" of a moral principle or symbol is a major cause of evil. This idea has been developed quite ably by others in recent years (see Baumeister, 1997, on "idealistic evil"; Glover, 1999, on tribalism; and Skitka & Mullen, 2002, on the "dark side" of moral convictions). We hope to add to these analyses of morality and evil by offering a map of moral space which may be helpful in 1 We note that Berlin's use of the word "monism" did not refer to the elevation of a single moral principle but rather to the belief that there is a single correct truth, which might involve several moral principles. Nonetheless, as we will argue, when any moral principles are sacralized, it can lead to the kind of certainty, self-righteousness, and even the willingness to "break eggs" in pursuit of those moral principles that Berlin warned about.