Abstract: Sympathy refers to caring about another to some degree as one cares for oneself. Empathy refers to the capacity to put yourself in the position of others to see things from their point of view. Empathetic preferences compare being one person in one situation with being another person in another situation. John Harsanyi showed that mild assumptions imply that to have empathetic preferences is the same thing as having rates at which the utility units of different people are to be traded off against one another. A consequence is that empathetic preferences have the same structure as Hamilton's rule, and so may have originated from strangers adopted into a clan being treated as surrogate kinfolk. But since empathetic preferences are cultural artifacts, they are subject to cultural evolution. The idea of an empathy equilibrium is introduced to capture the medium-run effects of such cultural evolution on empathetic preferences.

Keywords: empathy, empathetic preferences, utility, revealed preference, interpersonal comparison, empathy equilibrium,