In a YouTube interview recently, Roger Penrose commented that one of his beefs with quantum mechanics (QM) was that it depends on consciousness collapsing a wave function. He said much more, but this struck me deeply. I have been struggling for years trying to verbalize my own brain-stem level suspicions. (To be clear, a Venn diagram with Penrose and myself overlap only insofar as we are both English speaking bipedal mammals.)

He also commented that by “wrong” he means “incomplete” and recalled that both Einstein and Schrodinger agreed on this. He noted that “incomplete” constitutes “wrong”. In another interview he comments that Schrodinger’s Cat was meant to illustrate that the superposition of a cat being both dead and alive was a problem that Schrodinger recognized. A cat cannot really be dead and alive simultaneously.

He said that while QM was about more than the evolution of a quantum state, it is also about measurement, but the measurement problem violates the quantum equation. QM gives the probability of a given state which is a superposition of probabilities.

QM is not my specialty, however, I have coursework in it like all chemists have had. In grad school I had quantum chemistry, again like all chem grad students have had, but it nearly did me in. Not having had a semester of diff eq, I was at a distinct disadvantage. Grad school QM goes well beyond the particle in a 1-dimensional box. The course consisted of mathematical derivations of the theory, but not much about the meaning in English. We were supposed to see the equations in their abstract purity and extrapolate to some kind of comfort level with notions our brains could grasp. It was based on the Copenhagen Interpretation of QM. Philosophically, the notion that the wave function would collapse on inspection by a brain was an idea that even today I cannot get past.

Penrose had a similar beef except that he is Roger Penrose and I’m some lesser ape gawping in from up the holler. Still, though I’m doomed to go to my grave with only very rudimentary understanding of QM, the concept of probability density all by itself as well as the spherical harmonics defining atomic orbitals has been a major benefit for my thinking. And for that I’m grateful.

Below is a cut & paste copy of text from Wikipedia outlining Penrose’s ideas-

Penrose’s idea is a type of objective collapse theory. For these theories, the wavefunction is a physical wave, which experiences wave function collapse as a physical process, with observers not having any special role. Penrose theorises that the wave function cannot be sustained in superposition beyond a certain energy difference between the quantum states. He gives an approximate value for this difference: a Planck mass worth of matter, which he calls the “‘one-graviton’ level”.^[1] He then hypothesizes that this energy difference causes the wave function to collapse to a single state, with a probability based on its amplitude in the original wave function, a procedure derived from standard quantum mechanics. Penrose’s “‘one-graviton’ level” criterion forms the basis of his prediction, providing an objective criterion for wave function collapse.^[1] Despite the difficulties of specifying this in a rigorous way, he proposes that the basis states into which the collapse takes place are mathematically described by the stationary solutions of the Schrödinger–Newton equation.^[4][5] Recent theoretical work indicates an increasingly deep inter-relation between quantum mechanics and gravitation.^[6][7] Wikipedia.

I just donated to Wikipedia so I don’t feel too bad about this cut & paste. Please donate to Wikipedia. We want to avoid a paywall being put up in front of it.