I’m looking into the history of QM interpretations and there’s some interesting deviations from the story as told in the quantum sequence. So, of course, single-world was the default from the 1920s onward and many-worlds came later. But the strangeness of a single world was not realized immediately. The concept of a wavefunction collapse seems to originate with von Neumann in the 1930s, as part of his mathematicization of quantum mechanics–which makes sense in a way, imagine trying to talk about it without the concept of operators acting on a Hilbert space. I haven’t read von Neumann’s book, but the 50s, 60s, and 70s discussions of a measurement problem seem to draw on him directly. And the idea that QM requires fundamental irreducible minds seems to date to Wigner’s “Remarks on the Mind-Body Question”, published in 1961. Wigner mentions that Heisenberg thought QM was fundamentally describing our knowledge of the world, but that seems different from consciousness specifically, causing collapse specifically, though I don’t know Heisenberg’s views well. What makes this weird is this is after many-worlds! Notably, DeWitt’s 1970 article which popularized many-worlds seems to associate the “consciousness-causes-collapse” thing with Wigner specifically, giving Wigner more credit for it than Wigner gives himself. It’s not quite correct to say that “consciousness-causes-collapse” originated with Wigner’s article, since the “Wigner’s friend” thought experiment was actually discussed by Everett. Unsurprisingly, since Wigner was a professor at Everett’s school, so they likely discussed these issues. So the deviation from the story in the quantum sequence is that “consciousness-causes-collapse” was not the default theory which many-worlds had to challenge. Instead, they were contemporary competitors, introduced at basically the same time, with the same motivation. Of course, it remains the case that single-world was the default, and Wigner was arguably just following that where it led. But the real “Copenhagen” opinion, it seems to me, was against talking about a picture of the world at all. To say that there is some non-linear irreversible consciousness-initiated collapse, actually occurring in the world, is already a heresy in Copenhagen.
I’m looking into the history of QM interpretations and there’s some interesting deviations from the story as told in the quantum sequence. So, of course, single-world was the default from the 1920s onward and many-worlds came later. But the strangeness of a single world was not realized immediately. The concept of a wavefunction collapse seems to originate with von Neumann in the 1930s, as part of his mathematicization of quantum mechanics–which makes sense in a way, imagine trying to talk about it without the concept of operators acting on a Hilbert space. I haven’t read von Neumann’s book, but the 50s, 60s, and 70s discussions of a measurement problem seem to draw on him directly. And the idea that QM requires fundamental irreducible minds seems to date to Wigner’s “Remarks on the Mind-Body Question”, published in 1961. Wigner mentions that Heisenberg thought QM was fundamentally describing our knowledge of the world, but that seems different from consciousness specifically, causing collapse specifically, though I don’t know Heisenberg’s views well. What makes this weird is this is after many-worlds! Notably, DeWitt’s 1970 article which popularized many-worlds seems to associate the “consciousness-causes-collapse” thing with Wigner specifically, giving Wigner more credit for it than Wigner gives himself. It’s not quite correct to say that “consciousness-causes-collapse” originated with Wigner’s article, since the “Wigner’s friend” thought experiment was actually discussed by Everett. Unsurprisingly, since Wigner was a professor at Everett’s school, so they likely discussed these issues. So the deviation from the story in the quantum sequence is that “consciousness-causes-collapse” was not the default theory which many-worlds had to challenge. Instead, they were contemporary competitors, introduced at basically the same time, with the same motivation. Of course, it remains the case that single-world was the default, and Wigner was arguably just following that where it led. But the real “Copenhagen” opinion, it seems to me, was against talking about a picture of the world at all. To say that there is some non-linear irreversible consciousness-initiated collapse, actually occurring in the world, is already a heresy in Copenhagen.