What experiments can teach us about justice and impartiality: vindicating experimental political philosophy

While psychologists and political scientists have long investigated issues of interest to philosophers, the development of political experimental philosophy has remained limited. This slow progress is surprising, given that political philosophers commonly acknowledge the relevance of empirical data for normative theorizing. In this chapter, we illustrate the importance of empirical data by outlining recent developments in three domains related to theories of justice, where empirical results reinforce or endanger popular philosophical theories. Our first showcase concerns the boundaries of the concept of fairness. While both libertarian thinkers and social egalitarians have united in rejecting the concept of natural injustice, we show that people do consider that unpreventable natural inequalities can be described as unfair. Second, we take the example of impartiality devices, such as the veil of ignorance or the idea of an impartial spectator, to show that such devices are efficient at shifting people’s intuitions in a more impartial manner. Third, we review empirical data on fairness intuitions to show that people conform to a pluralist theory of justice, valuing desert, needs-satisfaction, and equality at the same time. However, distribution according to desert enjoys a privileged position: people mostly care for the satisfaction of basic needs of deserving recipients, and people are willing to tolerate large inequalities in meritocratic contexts. The centrality of desert leads to dilemmas for mainstream egalitarian theorists, as theories that do not recognize the value of desert could fail to find support or legitimacy within the population.