In the 1920’s, after centuries of dispute over whether light is a wave or particles, Bohr devised the compromise that holds today, that they are complementary views so both are true, and nothing better has been found since:
“…nobody has found anything else which is consistent yet, so when you refer to the Copenhagen interpretation of the mechanics what you really mean is quantum mechanics.” (Davies & Brown, 1999), p71.
In this don’t ask, don’t tell policy, a photon can be a wave when we don’t look, as long as it’s a particle when we do, so physics can apply particle or wave equations as convenient. In no pond do rippling waves behave like particles and on no table do billiard-balls behave like waves, but Bohr managed to sell the big lie [Note 1] that light is a wavicle. As Gell-Mann said in his 1976 Nobel Prize speech:
“Niels Bohr brainwashed a whole generation of physicists into believing that the problem (of the interpretation of quantum mechanics) had been solved fifty years ago.”
Figure 3.4 shows the options available. Physical realism, that only physical things exist, doesn’t let waves be particles, so there is the physical world but no quantum world (Figure 3.4a). But how then are physicists who use quantum waves to predict atomic events different from witchdoctors who use spirits to heal people, as both invoke what is imaginary?
To avoid this, Copenhagen dualism was that the quantum world did exist for physicist’s equations, but otherwise it didn’t, so in effect, both the physical world and the quantum world exist somehow (Figure 3.4b). But that a quantum world existed for the convenience of physics was an admission of failure, not a theory advance (Audretsch, 2004), p14.
This was the beginning of fake physics, where what is imaginary can cause real events if the equations work. Yet even as he publicly accepted quantum world, in private, Bohr denied that it existed at all. He wanted the best of both worlds, but like Descartes’ mind-body dualism earlier, Copenhagen dualism is a mystical marriage of convenience between incompatible domains, accepted by those who want it to be true.
Figure 3.4c shows the quantum realism alternative to physical realism and Copenhagen dualism, that physical events are a subset of quantum events. Now reality is quantum not physical, and it generates the physical world within it, so classical mechanics is a subset of quantum mechanics. What then are the properties of this reality, or as Wheeler put it, how come the quantum?
Note: A “big lie” is a statement so outrageous that people think it must be right or it wouldn’t be said.