This article presents 7 simple models of the relationship between cognitive empathy (mental perspective taking) and emotional empathy (the vicarious sharing of emotion). I consider behavioral outcomes of the models, arguing that, during human evolution, natural selection may have acted on variation in the relationship between cognitive empathy and emotional empathy resulting in two separable, complementary systems. I predict the existence of 4 empathy disorders using a concept of empathic imbalance. I propose hypotheses about the psychology of autism, antisocial personality disorder, schizoid personality disorder, and Williams syndrome. This approach generates new predictions and integrates some previous theoretical work by various authors. (Contains 1 table.)