Dear Robert,
Reading your essay, I tend to agree with many of your conclusions, but there was one particular passage that does not seem to be correct to me. In the description of the double slit experiment, you describe the particle detectors as only counting particles. I think it is critical to consider that they also record the location of the particle detection which, as it happens, coincides with the apparent path of a wave. You stated:
"In double-slit experiments, much is often made of the fact that the distribution of particles looks like an interference pattern, even when the particles are sent through the apparatus one at a time, as if that actually matters. Well, it might matter if a detector tried to measure a wave-like property like frequency or phase or a superposition. But neither of the systems just described even attempt to do that. They simply count particles and infer the frequency from the counts. It does not matter if the particles arrive all at once or one-at-a-time."
"Why does an 'interference pattern' occur at all? Because the slits do not have Gaussian responses. They have Sinc-function-like responses, whose combination just happens to look like an interference pattern. There is no wave behavior. There are just particles in a correlated energy/frequency state. But detectors like those described do not really distinguish between particles and waves; in effect, they just count received energy quanta and then make an inference, not a measurement; an inference based on a priori information."
IMO, the interference pattern occurs because the spatial distribution of particle detections occurs only along the path of their propagating wave forms. It is the obvious interference pattern that provides physical evidence of the wave distribution from each slot, even when a single quanta passes through the system at any time.
It is for this reason that I conclude that particles propagate only as waves, and are localized as discrete particles.
BTW, I'm only a retired information systems analyst - not at all a physicist or mathematician, so my perspective may differ. I found your article interesting to the extent that I could follow it, but frankly I had envisioned a somewhat different discussion based on the title.
As Benjamin Dribus discussed in his essay, theories are evaluated on the basis of their success in explaining and predicting physical phenomena. However, I think that far too often a mathematical formulation that successfully predicts the outcome physical processes are merely presumed to accurately represent the explanation of the causal process. In the example I'm most interested in, general relativity (GR) is thought to accurately describe how gravitation physically works, in contrast to Newton'attractive force'. However, IMO GR very successfully describes only the effects of gravitation in the context of the described abstract system of dimensional coordinates. I certainly do not think that the dimensions of spacetime directly cause any physical effects...
I think similar presumption that a mathematical formulation that accurately predicts observed physical phenomena, like those requiring compensatory dark matter or dark energy, for example, do not necessarily describe the actual physical processes producing those effects any more than Ptolemy's ability to predict the motions of planets in the sky was proof of the physical process presumed to produce those phenomena. Well, maybe just a little...
Yours is a very interesting essay - I enjoyed it.
Sincerely, Jim