Psychological Contributions to Philosophy: The cases of Just War Theory and Nonviolence

Moral philosophy has laid out theories for conduct during wartime and the use of nonviolence. Yet, how do these theories map onto people’s actual behavior? A first set of studies tested people’s use of Just War principles in evaluating wartime conduct. Adelman, Orazano and Leidner show that people utilize the jus in bello principles of necessity, discrimination and proportionality to judge the justness of wars, but to different degrees, depending on their moral principles. A second set of studies experimentally investigates whether nonviolence is a viable strategy for social movements struggling against oppression. Adelman, Orazano and Leidner provide converging evidence for a model of nonviolent struggles in Bahrain, Iran, and the United States, demonstrating that nonviolent movements are more effective at generating support and increasing membership. In sum, people do largely seem to behave as philosophical theories have prescribed, but sometimes in a way limited by psychological bias.