Our recent podcast “Dialectical Materialism, Marxist Realism and Quantum Mechanics” received some pushback in the form of Facebook comments, where it was claimed that we fell into idealism and that we did not treat the topic of Bohmian mechanics sufficiently seriously. Furthermore, we received a letter, “Bohmian Mechanics,” which referred to Bohmian mechanics as the “Bohmian or ontological interpretation of quantum mechanics” [emphasis mine], a tall order. The letter then goes on to claim that this interpretation “is ontological because it states that there are particles with well-defined position and momenta in nature, it is also realistic for this reason.” The rest of the letter mentions the usual Bohmian mechanics constructions/equations: it postulates a solution for the Schrodinger equation, and identifies its constituent parts with position and velocity of the particle. A few graphs follow and the letter ends. A more elaborate explanation on Bohmian mechanics, including why this solution shape is used, can be seen on the Wikipedia page for pilot wave theory (another name for Bohmian mechanics) if the reader is interested.
First, I would like to note that the point of this episode was to zoom in into the life of V. A. Fock and explore how his dialectical materialism productively informed his philosophy of quantum mechanics to highlight how dialectical materialism is more than a dogma. It is also worth noting that even if Fock polemicized against the “Copenhagen interpretation,” there is no such thing as a pure Copenhagen interpretation. We can distinguish three people primarily responsible for the interpretation: Niels Bohr, Werner Heisenberg, and Erwin Schrödinger, but they each had very different thoughts about what quantum mechanics taught us about the world. Fock polemicized against Niels Bohr’s interpretation, which was the most complex of them all, and the most compatible with realism, as Karen Barad has shown in her work Meeting the Universe Halfway.
What we are usually taught even at the university level filters down to popular culture as a take on the early Heisenberg vision of the uncertainty principle: the fact that things do not have definite properties and only take values when we measure them. An absurd consequence of this is the “Schrödinger’s cat” thought experiment, which postulates a half-dead/half-alive cat that only “collapses” into one of the states when it is observed. Schrödinger took this thought experiment very seriously and postulated that unless there is an intelligent agent in the loop, the cat is indeed in a superposition of dead and alive.
Marxists feel a natural repulsion to this interpretation because it seems to imply that realism is not correct — that things only take definite values when they are observed. This repulsion is to a certain degree natural, as the bourgeois interpretation of the word hinges on the importance of the individual point of view, but it is also brought about by the influence of Lenin’s Materialism and Empiriocriticism. However, as Fock and Barad show, the Bohrian interpretation of quantum mechanics can be easily made compatible with realism, as it is not about inherent uncertainty that is dependent on observation but about ontological complementarity. While (the early) Heisenberg and Schrödinger talked about the importance of measurement, Bohr never bought into this. He even rejected the “projection principle,” which in a simplified manner means that measurements do certain things to a particle and can be incorporated into QM’s formalism to yield the uncertainty principle from the equations. What Bohr instead said was that it doesn’t make sense to ask an object to behave both as a wave (and know its velocity) and as a particle (and know its position). An object cannot behave both ways, and you cannot design apparatuses to capture both behaviors simultaneously. Measurement uncertainty is not a priori, but is a consequence of this. This crucial difference between Bohr and Heisenberg is not well understood, and what is lumped together and taught as the “Copenhagen interpretation” has less to do with Bohr’s philosophy and more to do with the early Heisenberg and liberalism’s idealism.
Faced with quantum mechanics and with a crude understanding of the uncertainty principle, it is natural to search for other solutions due to the discomfort of the philosophical questions raised. Some Marxists (and other people who like their reality to be completely transparent to their intuitions) have found comfort in Bohmian mechanics. This is where we see the author of the letter (and other critics), who claims that Bohmian mechanics is realistic and ontological [!!] because position and velocity are well defined, and it almost seems as if they see it as the only interpretation with these characteristics by the phrasing used. However, after the explanation of complementarity, does one really need position and velocity to be defined for something to be realistic? Or can we expand our understanding of reality a bit to accept that position and velocity are things that are only distinguishable at our scale while at the quantum scale they are not?
For a long time, Bohmian mechanics was buried because the “hidden variables” present in the theory gave way to the experimental confirmation of Bell’s inequality. One can reformulate the theory to survive Bell’s inequality, but it is my honest opinion that Bohmian mechanics cannot adequately do so without falling into an immense amount of adhocism. This does not mean that Bohmian mechanics is wrong, only that it seems unnecessarily complicated to me, and that we should not hold on to it as the only realistic and ontological alternative. Bohmian mechanics has seen a recent revival due to the recent “walker” experiments in a fluid which showed what seemed like a beautiful analog to quantum mechanics: a droplet sitting on a fluid surface and producing its own wave pattern on this surface. But however much this walker shows analog behavior to some quantum experiments, walkers are not able to show quantum entanglement or other properties.
Now, Marxists might find pilot-wave theory attractive because we do not, and never will, intuitively understand the concepts behind quantum mechanics, and pilot-wave dynamics matches both our intuitions and the philosophical demands of Materialism and Empiriocriticism. I do not presume to understand QM, even after decades in the field of physics. However, I do believe that we can do better than grasp at discredited theories in vain and scream “Idealism!” at those who don’t exactly follow our philosophical precepts. Furthermore, this is a rather sad legacy of Lenin’s MEC, written primarily as a political polemical against the Oztovists in a factional fight that used philosophy as an excuse to punch down. With Lenin’s signature on it, MEC became an unimpeachable part of the canon, and it has made us stuck. It has us thinking that we are doing high-stakes political interventions when discussing rather complex philosophical concepts (think Andreas Malm vs Jason Moore), and causing us to see ghosts of CIA-financed postmodernist idealism everywhere, rather than getting Marxists to reckon with the complexity of nature, the possibilities of non-human agency, and the rather unprivileged position of humans in the universe.
I hope this letter serves as a way of leaving behind that past.
Comradely,
Renato Flores
