In effect this implies that the entire universe is described by a gigantic wavefunction: as Everett called it in his thesis, the ‘universal wavefunction’. This begins as a superposition of all possible states of its constituent particles – it contains within it all possible realities. As it evolves, some of these superpositions break down, making certain realities distinct and isolated from one another. In this sense, worlds are not exactly ‘created’ by measurements; they are just separated. This is why we shouldn’t, strictly speaking, talk of the ‘splitting’ of worlds (even though Everett
...more
