Dear Philip,
Though you know an awful lot more about physics than I do and your excellent essay is written much better than mine, I do think, with all respect, that I'm a few crucial steps ahead of you.
Causality only makes sense in a Big Bang Universe. The problem is that a BBU lives in a time continuum not of its own making, so the concept of cosmic time refers to an imaginary observation post outside the universe, which, as I argue in my essay (''Einstein's Error'') is illegitimate, scientifically and hence is an invalid concept. If without a 'cosmic clock' showing cosmic time, we cannot determine what precedes what in an absolute sense, whether the emission of a photon at A precedes its absorption at B, then we can no longer attribute light a (finite) velocity. Instead, it refers a property of spacetime, which is something else entirely.
The problem is that we confuse causality with rationality, even though it leads nowhere.
If we understand something only if we can explain it as the effect of some cause, and understand this cause only if we can explain it as the effect of a preceding cause, then this chain of cause-and-effect either goes on ad infinitum or we end up at some primordial cause which, as it cannot be reduced to a preceding cause, cannot understood by definition, so causality ultimately cannot explain anything. If, for example, you invent Higgs particles to explain the mass of other particles, you'll eventually find that you need some other particle to explain the Higgs particle, a pre-Higgs particle which in turn needs another particle and so on and on.
A universe which has a beginning is a caused universe, that is, is created by some outside intervention. As I refuse to believe in some Creator, I had to assume that we live in a universe which creates itself out of nothing, without any outside intervention. In such universe particles and particle properties necessarily must be as much the product as the source of their interactions, which explains the why of the uncertainty principle. Since in a Self-Creating Universe particles cause, create one another, they explain each other in a circular way. Here we can take any element of an explanation, any link of the chain of reasoning without proof, use it to explain the next link and so on, to follow the circle back to the assumption we started with, which this time is explained by the foregoing reasoning, that is, if our reasoning is sound and our assumptions are valid. If we have more confidence in a theory as it is more consistent and it is more consistent as it relates more phenomena, makes more facts explain each other and needs less additional axioms, less more or less arbitrary assumptions to link one step to the next, then any good theory has a tautological character, fitting a self-creating, self-explaining universe. The circle of reasoning ought to work equally well in the reverse direction.
Whereas everybody investigates nature by trying to explain observed phenomena, I started from a reverse-engineering point of view: How can a universe create itself out of nothing, without any cause, any outside intervention? Can I understand this self-creation process rationally? As I could not argue every step of my reasoning in so few pages, some conclusions of the essay may seem to fall out of the blue: for a more extensive study, you might take a look at my website www.quantumgravity.nl Though you'll find that I'm an awful writer, I think you'll find plenty of useful ideas to use as whetstone to sharpen your own thoughts. I would be obliged if you'd care to take the effort to read and comment on it.
Anton