Erwin Schrödinger on the Many Worlds of the Wave Function

Schrödinger once raised the possibility that the wave function’s “great many alternatives may not be alternatives [at all], but all really happen simultaneously”. He admitted that this idea may “seem lunatic” to “quantum theorists”. The physicist David Deutsch believes these words to be the earliest known reference to what came to be called “many worlds”.

Much that’s controversial and (as it’s often put) weird about quantum mechanics (or at least the wave function) is discussed in the following passage, which was once spoken by Erwin Schrödinger:

“Nearly every result [the quantum theorist] pronounces is about the probability of this or that or that … happening — with usually a great many alternatives. The idea that they may not be alternatives but all really happen simultaneously seems lunatic to him, just impossible. He thinks that if the laws of nature took this form for, let me say, a quarter of an hour, we should find our surroundings rapidly turning into a quagmire, or sort of a featureless jelly or plasma, all…