Dear Lawrence Crowell,
You begin your essay with a well written summary of physics history, beginning with "the motion of particle executes little variations to find the proper path", then undergoing a "radical shift [from] variation of the least action in classical physics [to] the path integral in the quantum mechanics of fields." Like some others in this essay contest, I am more inclined to attempt to derive quantum theory from classical fields than vice versa, so I particularly liked your explanation that "constructing a propagator for a field on that very same field" leads to problems.
In analyzing the limits of space-time, you point out that we are limited by the fact that beyond a certain point, our probe creates black holes that hide the information from us. [That's one reason I treat non-relativistic quantum mechanics and weak field gravity, where we know, at least potentially, whereof we speak.] Thus you point out, "space-time itself is a barrier to the complete specification of an observable." You then say "information conservation demands...". If you'd care to comment on the grounds on which you base a belief in "information conservation" I would be interested. I know it is often assumed nowadays, but I'm not sure on what it is based. I assume you do not begin with quantum error correcting code to achieve this.
While I don't buy either quantum gravity or supergravity, nevertheless your observations about "the breakdown in the ability to measure everything about the universe" are quite interesting, as is your conjecture that this implies time, unitarity, locality, and causality to be emergent. You seem to agree with Philip Gibbs, so I suspect these are the waters the "math beyond physics" school swim in today. In my previous essays and in my dissertation, "The Automatic Theory of Physics", I presented logic and mathematics as emergent, so I tend to question any ultimate conclusions based on math that go beyond physical barriers to observation. Frank de Meglia may have as much claim to this territory as anyone.
Nevertheless, having chosen to play the game of 'math beyond physics', you do a bangup job of it, ending up with one electron, one quark, one photon in a universe based on underlying quantum error correction codes.
Best of luck in the contest,
Edwin Eugene Klingman