Urban superposition

‘Now let us,’ says Freud in Civilization in its Discontents, ‘by a flight of imagination, suppose that Rome is not a human habitation but a psychical entity with a similarly long and copious past—an entity, that is to say, in which nothing that has once come into existence will have passed away and all the earlier phases of development continue to exist alongside the latest one. This would mean that in Rome the palace of the Caesars and the Septizonium of Septimus Severus would still be rising to their old height on the Palatine … the same piece of ground would be supporting the church of Santa Maria sopra Minerva and the ancient temple over which it was built. And the observer would perhaps only have to change the direction of his glance or his position in order to call up the one view or the other.’ It's an odd thing that Freud immediately steps back from his psychical thought experiment (‘There is clearly no point in spinning our phantasy any further, for it leads to things that are unimaginable and even absurd’). Other writers have not been so coy, most recently, of course, Mièville’s City and City. But the central point here is worth stressing; that actually this precisely how cities operate: we walk semiconsciously through the semipermanence of all the city all of time.