As I state my questions, there are likely to be errors that I would appreciate being corrected. Beyond that, however, if the gist of the questions can be salvaged after correcting these errors, I would also like answers to your version of the questions. Both Feynman's summation over histories and Everett's MWI start off from the collection of possible events at any given moment. From there Feynman keeps them all in one universe and performs path integrals, while Everett has each path lead an independent existence in its own universe. Nonetheless, there is the gut feeling that the two have probably been unified somewhere. If so, could someone outline how or give me a link (that doesn't lead to a to-be-paid-for article)? Secondly, in mathematical logic, the theory of Kripke frames is sometimes called many worlds, and one can see a superficial resemblance to the states of quantum physics, but has this ever been pursued?