Books: Upside Down and Vice Versa A CONFLICT OF VISIONS: IDEOLOGICAL ORIGINS OF POLITICAL STRUGGLES

It is a murky business, trying to specify the ideological differences between Democrats and Republicans, boll weevils and gypsy moths; even the traditional differences between liberals and conservatives get cloudy when people call themselves moderates, pragmatists, middle-of-the-roaders. Thomas Sowell, an economic historian at the Hoover Institution at Stanford University, would like to start all over again. He has divided people according to two different views of human nature: the "constrained vision" and the "unconstrained vision." "Conflicts of interests dominate the short run," he says, "but conflicts of visions dominate history."

A vision, as Sowell uses the term, is not some mystical...