We live in strange times. We also live in strange places: each in a universe of our own. The people with whom we populate our universes are the shadows of whole other universes intersecting with our own. Being able to glance out into this bewildering complexity of infinite recursion and say things like, 'Oh, hi, Ed! Nice tan. How's Carol?' involves a great deal of filtering skill for which all conscious entities have eventually to develop a capacity in order to protect themselves from the contemplation of the chaos through which they seethe and tumble.
Douglas Adams (2009). “Mostly Harmless”, p.100, Pan Macmillan