Hypotheticopolis is a city which is a sort of microcosm of the whole world, and also happens to be free from facts. It is often treated as a testing ground for moral and philosophical problems that confront the Free World (e.g. whether torture should be allowed). And for a good reason too: for, to refer to facts instead of Hypotheticopolis will be very treasonous indeed. Besides "Hypotheticopolis", this wondrous city is also known by many other names, such as "Twin Earth": On Twin Earth, a brain in a vat is at the wheel of a runaway trolley.