Many have long chastised the Left for its supposed naivete about human nature. To these critics, the Left thinks that human beings are by nature good. Left-wingers of all stripes of course recognize that there are many evils in the world — otherwise they wouldn’t be on the Left. But, the criticism goes, left-wingers refuse to attribute these evils to human nature, instead blaming flawed institutions and culture. Remove these social sources of human corruption, and class rule and selfish competitiveness will give way to our natural benevolence. Some project even more dazzling hopes, imagining a future mankind operating at a far higher intellectual and aesthetic level than it does now.

The Left’s critics argue that this idea reveals an impoverished understanding of human nature. The truth, they say, is that we are flawed, sinful beings from the very beginning, and that it is utopian to imagine any social tinkering could fix that.

Conservatives have often made this sort of argument. In his book Intellectuals and Society, the right-of-center economist Thomas Sowell posits that the core difference between Left and Right boils down to a “conflict of visions.” According to Sowell, the Left holds that human suffering is largely the fault of society: “Oppression, poverty, injustice and war are all problems of existing institutions — problems whose solutions require changing those institutions, which in turn requires changing the ideas behind those institutions.” Sowell contrasts this with the largely conservative “tragic vision” that recognizes “the inherent flaws of human beings are the fundamental problem, and social contrivances are simply imperfect means of trying to cope with those flaws — the imperfections of these contrivances being themselves products of the inherent shortcomings of human beings.”