“Long before we’ve had the chance to become familiar with our loved one, we may be filled with the curious sense that we know them already.  It seems as though we’ve met them before, in a previous life perhaps, or in our dreams.  In Plato’s Symposium, Aristophanes explains this feeling of familiarity with the claim that the loved one was our long-lost “other half” whose body we had originally been stuck to.  In the beginning, all human beings were hermaphrodites with double backs and flanks, four arms and four legs, and two faces turned in opposite directions on the same head.  These hermaphrodites were so powerful and their pride so overweening that Zeus was forced to cut them in two, into a male and a female half—and from that day, each man and each woman has yearned to rejoin the half from which he or she has been severed.”

from “On Love,” by Alain de Botton