"Please relax," said the voice pleasantly, like a stewardess in an airliner with only one wing and two engines one of which is on fire, "you are perf… - Douglas Adams

The Total Perspective Vortex derives its picture of the whole Universe on the principle of extrapolated matter analyses.To explain — since every piece of matter in the Universe is in some way affected by every other piece of matter in the Universe, it is in theory possible to extrapolate the whole of creation — every sun, every planet, their orbits, their composition and their economic and social history from, say, one small piece of fairy cake. The man who invented the Total Perspective Vortex did so basically in order to annoy his wife.

"What do you get if you multiply six by nine?"
"Six by nine. Forty two."
"That's it. That's all there is."
"I always thought something was fundamentally wrong with the universe"

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. So give your kid a break, okay?