After reading Hawking's Grand Design I'm curious about what appears to be an inconsistency in his reasoning. His basis for the multiverse is that every permutation of M-Theory corresponds to different physical laws and that every possible history is relevant for predicting the state of a system--such as the pattern produces in the familiar two slit experiment. However it would seem that if in fact one has to sum over all states one would have to sum over all the states where the laws, or at least constants, of physics were different. As I understand it Hawking is saying that each multiverse corresponds to a different set of laws based on a different M-Theory geometry. Yet if some sort of random selection occurs at the start of each universe it would seem that at all subsequent times in that universe the probability for a path based on all possible M-theory variants would be non-zero. Yet that's clearly not the case since if it were we'd be seeing results inconsistent with our calculations which are based on a single set of constants. Another way to ask this question is to ask by what mechanism Hawking proposes to cut off all but one instantiation of M-theory--or at least one set of constant values--once a new universe is formed. Am I missing something or is this something Hawking doesn't address. Thanks for any help.