You might in any case want to ask: where are all these ‘other worlds’ anyway? The usual answer is that they are in Hilbert space – the mathematical construct that contains all the possible solutions of the variables in the Schrödinger equation. But Hilbert space is a construct – a piece of math, not a place. As Asher Peres has put it, ‘The simple and obvious truth is that quantum phenomena do not occur in a Hilbert space. They occur in a laboratory.’
