Most people would agree that it is desirable for a society to be fairly cohesive, such that people have a real sense of community and common purpose with one another as fellow members of the larger society. Likewise, few would disagree that it is desirable that a society be fairly democratic, so that each citizen has the opportunity to influence governmental decision-making. Only if there is such cohesion and democracy will a political system—and the power that it vests in the government— be broadly respected as legitimate. Consider therefore each of the following societal objectives:
Promote Social Cohesion
As the historian Tony Judt has written, “Inequality is corrosive.. .it rots societies from within...it illustrates and exacerbates the loss of social cohesion” (quoted at the conclusion of Strauss-Kahn 2010). Many people will not have a sense of community with their fellow citizens if there are significant economic and social differences among individuals that are not readily attributable to differential effort or desert. Likewise, social cohesion will be difficult to sustain if there are substantial economic and social differences among ethnic groups—especially disparities in the extent to which different groups are represented in powerful and prestigious decision-making positions. The achievement of a high degree of social cohesion thus depends upon the limitation of economic and social inequalities across both individuals and ethnic groups.
The distributions of all of the economic variables under consideration—income, consumption, wealth, and access to public services—affect social cohesion, because they all affect social as well as economic status. The configuration of inequality in these variables that is most critical to the promotion of social cohesion is arguably the degree of bipolarization, because the prospects for community and common purpose are undermined if the economic status of a large proportion of the population is far above the median and that of another large proportion is far below it. By the same token, if there are significantly-sized ethnic groups whose economic status is far above the societal median and/or far below it, social cohesion becomes much more difficult to sustain.
-  Anderson (2002) has argued persuasively that making the group composition of the societal elitemore broadly representative of the population as a whole is the single most important rationale forpositive discrimination in favour of historically marginalized groups.