They are sites that have a general relation of direct or inverted analogy with the real space of Society

Here Foucault presents the dual nature, and thus contradiction, of the definition of utopia. Direct and inverted analogies are contradictory, yet a utopia can contain both. And yet since both are in a relationship to the “real space of Society,” both remain similar in their implied un-reality. Utopias, then, are imagined spaces, a potential energy, a vacuum which society wishes to fill.

Utopias are unreal, but societies are real. Society exists in “real space.” The only caveat is that societies are unreal as well; you can’t show me a society on a plate. Society is capitalized because it is treated as a metaphysical subject, another illusion created by the mind to make sense of things. A Utopia goes further, then; whereas Society is an intangible construct of real human interactions, Utopia is an intangible, entirely fictional construct of a Society that is in “directed or inverted analogy” to it. Thus Utopias are doubly unreal. So the reader must be very intrigued to know how heterotopias relate to all this: do they revert back to the real? Or do they instead stack again, one further step removed from the real than the Utopia?