I wonder if each path in a Feynmen path integral might represent another path from an observer in a different frame of reference. Perhaps if another FOR is accelerating, it may appear as if the path we might consider looks distorted from that other FOR. If so, then QM is accounting for every possible observer at the same time, of all observations at once must agree. I've not thoroughly thought this out. Feel free to shoot it down if you'd like. Thanks.