A crux of Plato’s Symposium is how beauty (to kalon) relates to the good. Diotima distinguishes beauty from the good, I show, to explain how erotic pursuits are characteristically ambivalent and opaque. Human beings pursue beauty without knowing why or thinking it good; yet they are rational, if aiming at happiness. Central to this reconstruction is a passage widely taken to show that beauty either coincides with the good or demands disinterested admiration. It shows rather that what one loves as beautiful does not appear good, a proposal with ramifications for ethical psychology.