26JUN22 Posted as a comment to this Quanta article. Probably won’t be published there until tomorrow.

Contextuality says that properties of particles, such as their position or polarization, exist only within the context of a measurement.

This is just the usual Copenhagen mush, that substitutes a feckless by-product of the pseudo-philosophy of mathematicism for scientific rigor. The rather irrational, anthropocentric view that a particle doesn’t have a position until it is measured is entirely dependent on the belief that the Schrodinger wavefunction is a complete and sufficient description of physical reality at the quantum scale. It is not.

The Schrodinger equation only provides a statistical distribution of the possible outcomes of a measurement without specifying the underlying physical processes that cause the observed outcomes. The only scientifically reasonable conclusion would seem to be that the equation constitutes an incomplete description of physical reality. The Copenhagen interpretation of QM – that the wavefunction is all that can be known is not a rational scientific viewpoint. In physical reality things exist whether humans observe them or not, or have models of them or not.

There has long been a known alternative to the wavefunction only version of QM that was championed by John Bell himself. In Bohmian mechanics, in addition to the wavefunction, there is a particle and and a guiding wave. In that context the wavefunction provides the outcome probabilities for the particle/guiding-wave interactions. Bohmian mechanics constitutes a sound scientific hypothesis; the Copenhagen interpretation (however defined) offers nothing but incoherent metaphysical posturing. As in:

The physicists showed that, although making a measurement on one ion does not physically affect the other, it changes the context and hence the outcome of the second ion’s measurement.

So what is that supposed to mean exactly, in physical terms? The measurement of one ion doesn’t affect the second ion but it does alter the outcome of the second ion’s measurement? But what is being measured if not the state of the second ion? The measurement of the second ion has changed but the ion itself is unaltered, because the “context” changed? What does that mean in terms of physics? Did the measurement apparatus change but not the second particle? It’s all incoherent and illogical, which is consistent with the Copenhagen interpretation I suppose, but that’s not saying much.

Bohmian mechanics makes short work of this matter. There are two charged particles, each with a guiding wave; those guiding waves interact in typical wave-like fashion in the 4 dimensional frame of electromagnetic radiation. The charged particles are connected in, by, and across that 4D frame. By common understanding, such a 4D frame has no time dimension. That is what accounts for the seemingly instantaneous behavior. That’s physics, it could be wrong, but it is physics. Contextuality is math; math is not physics.

Theoretical physics in its current guise is an unscientific mess because physical reality has been subordinated to mathematical and metaphysical considerations. And so we have the ongoing crises in physics in which the standard models are so discordant with physical reality in so many different ways that it seems difficult to say what precisely is wrong.

The simple answer is that you can’t do science that way. Attempting to build physics models outward from the mathematical and metaphysical realms of the human imagination is wrong. Basing those models on 100 year old assumptions and holding those outdated assumptions functionally inviolable is wrong.

Science has to be rooted in observation (direct detection) and measurement. Mathematics is an essential modeling tool of science but it is only a tool; it is not, of itself, science.

Theoretical physics, over the course of the 20th century, devolved into the study of ever more elaborate mathematical models, invoking ever more elaborate metaphysical conjectures of an invisible realm knowable only through the distorted lenses of those standard models.

Physical reality has to determine the structure of our theoretical models. Currently theorists with elaborate models dictate to scientists (those who observe, measure, and experiment) that they must search for the theoretical components of their models, or at least some signs and portents thereof. Failure to find the required entities and events does not constitute a failure of the model however, only a failure, thus far, of detection (dark matter, etc.) or the impossibility of detection (quarks, etc.). In any event the models cannot be falsified; they need only be modified.

Modern theoretical physics is an exercise in mathematicism and it has come to a dead end. That is the crisis in physics and it will continue until the math first approach is abandoned. It is anybody’s guess when that will happen. The last dark age of western science persisted for a millennium.