Jul 14, 2025 09:32 PM
https://aeon.co/essays/how-wittgenstein-...um-physics
"By the late 20th century, dozens of other interpretations had appeared under exotic names: the many-worlds theory, superdeterminism, consistent histories, the modal interpretation, superselection, Bohmian mechanics, Lindblad equations. I even invented my own: dynamic histories. While a few, like mine, proposed new theories that could come into conflict with quantum mechanics, most of them don’t. They are metaphysical, not physical.
The big question lurking behind all this is: what does the wavefunction mean? Does it represent something real or not? Most interpretations are ‘realist’ in the sense that they assume the wavefunction is a real entity and then go on to explain what it represents – but a few say it doesn’t exist at all, such as Quantum Bayesianism or QBism, as it is known. QBism owes its existence to the work of Wittgenstein’s friend and contemporary Frank Ramsey, who developed an anti-realist interpretation of probability. QBism holds that the wavefunction is purely an encoding of human uncertainty, representing a spectrum of probabilities that is updated when we make an observation. So the quantum wavefunction is not about objective reality at all, but about our future observations. QBism therefore refutes the Platonic idealism of the wavefunction and declares it to be a mere mathematical quantification of our beliefs.
Plenty of physicists have grown tired of this debate and its seemingly endless and unsatisfying arguments between realists and anti-realists. They want us to ‘Shut up and calculate!’ in the words of the physicist David Mermin: to stop trying to interpret quantum mechanics at all and get back to doing it. Philosophers, on the other hand, tend to dismiss this latter group as being philosophically ignorant. There’s a suspicion that, deep down, such physicists simply possess a metaphysics that they don’t want to admit, because they don’t want to come down on the side of an interpretation that has no scientific backing.
Yet those who follow Mermin’s injuction have a friend in one of the great philosophical minds of the 20th century – one who provides not only support for their position, but philosophical reasoning for why it is the only correct one..."
"By the late 20th century, dozens of other interpretations had appeared under exotic names: the many-worlds theory, superdeterminism, consistent histories, the modal interpretation, superselection, Bohmian mechanics, Lindblad equations. I even invented my own: dynamic histories. While a few, like mine, proposed new theories that could come into conflict with quantum mechanics, most of them don’t. They are metaphysical, not physical.
The big question lurking behind all this is: what does the wavefunction mean? Does it represent something real or not? Most interpretations are ‘realist’ in the sense that they assume the wavefunction is a real entity and then go on to explain what it represents – but a few say it doesn’t exist at all, such as Quantum Bayesianism or QBism, as it is known. QBism owes its existence to the work of Wittgenstein’s friend and contemporary Frank Ramsey, who developed an anti-realist interpretation of probability. QBism holds that the wavefunction is purely an encoding of human uncertainty, representing a spectrum of probabilities that is updated when we make an observation. So the quantum wavefunction is not about objective reality at all, but about our future observations. QBism therefore refutes the Platonic idealism of the wavefunction and declares it to be a mere mathematical quantification of our beliefs.
Plenty of physicists have grown tired of this debate and its seemingly endless and unsatisfying arguments between realists and anti-realists. They want us to ‘Shut up and calculate!’ in the words of the physicist David Mermin: to stop trying to interpret quantum mechanics at all and get back to doing it. Philosophers, on the other hand, tend to dismiss this latter group as being philosophically ignorant. There’s a suspicion that, deep down, such physicists simply possess a metaphysics that they don’t want to admit, because they don’t want to come down on the side of an interpretation that has no scientific backing.
Yet those who follow Mermin’s injuction have a friend in one of the great philosophical minds of the 20th century – one who provides not only support for their position, but philosophical reasoning for why it is the only correct one..."
