Game Theory and Morality Moshe Hoffman , Erez Yoeli , and Carlos David Navarrete Introduction Consider the following puzzling aspects of our morality: 1. Many of us share the view that one should not use people, even if it benefits them to be used, as Kant intoned in his second formulation of the categorical imperative: “Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end” (Kant, 1997 ). Consider dwarf tossing, where dwarfs wearing protective padding are thrown for amusement, usually at a party or pub. It is viewed as a violation of dwarfs’ basic dignity to use them as a means for amusement, even though dwarves willingly engage in the activity for economic gain. Many jurisdictions ban dwarf tossing on the grounds that the activity violates dwarfs’ basic human rights, and these laws have withstood lawsuits raised by dwarfs suing over the loss of employment (!). 2. Charitable giving is considered virtuous, but little attention is paid to how just the cause or efficient the charity. For example, Jewish and Christian traditions advocate giving 10 % of one’s income to charity, but make no mention of the importance of evaluating the cause or avoiding wasteful charities. The intuition that giving to charity is a moral good regardless of efficacy results in the persistence of numerous inefficient and corrupt charities. For example, the Wishing Well Foundation has, for nearly a decade, ranked as one of CharityNavigator. M. Hoffman (*) • E. Yoeli Program for Evolutionary Dynamics , Harvard University , One Brattle Square, Suite 6 , Cambridge , MA 02138 , USA e-mail: [email protected] C.D. Navarrete Department of Psychology, and, the Ecology, Evolutionary Biology and Behavior Program , Michigan State University , East Lansing , MI , USA © Springer International Publishing Switzerland 2016 T.K. Shackelford, R.D. Hansen (eds.), The Evolution of Mo