Good to hear from you again Hans!
Interesting - and short - read. I agree that a discussion (only) of fundamentals should be kept short!
I see that you are still very interested in Hilbert's work (e.g. Hilbert's Program) and of course Hilbert Space. I once gave a talk at MathFest 2011 on this general subject. I must then point out that his definition of completeness is not considerable, but that "consistency" is crucial. So in many ways we must consider Takeuti's proof that a consistent mathematical system must be finitary.
This opens up the discussion to include representation theory.
It is not at all clear to me what sort of finite particle a quaternion algebra might represent, though. And whether the formulation (or geometry) is causal. But it is clear that the No-Boundary Wave Function is causal and its variables easily assigned to finite-geometric metrics.
Feel free to investigate these fundamental ideas further
https://fqxi.org/community/forum/topic/3092
best,
Wayne
