This article develops and tests the social mapping hypothesis, namely, that the neurophysiology of dreaming may have been a preadaptation for the evolution of hominid consciousness. Dreaming locates the dreamer in emotionally salient social space, a trait possibly derived from hippocampal spatial mapping. This skill in self-imaging and location can be correlated with the broader social brain hypothesis. Dreaming is thus expected to share significant features with consciousness, symbolization, and cognitive mechanisms pertaining to culture; and it is shown to do so. Rival models of consciousness and dream function are compared and assessed, and Flanagan's assertion that dreaming is epiphenomenal is challenged.