A paradox is a proposition in (alleged) contrast with common sense. All science is replete with paradoxes. Economics is not an exception. This paper is focused on two widely discussed paradoxes: the Mandeville paradox (and the associated idea of an 'invisible hand') and the Prisoners' Dilemma...

We present an axiomatic model of choice involving two agents, motivated by the experimental evidence on non-selfish preferences. We distinguish two classes of social preferences, depending on whether they are or not separable. Altruism and spite (Andreoni & Miller, 2002; Cox et al., 2007) are...