The best current theory suggests that our universe is just one
universe in a “multiverse” -- a vast number of universes, each
bubbling up randomly out of the foam on the surface of the
multiverse, like so many bubbles in the bathwater, each one the
result of some totally random event. (p. 36) If the multiverse
hypothesis is correct, then, while our universe began at the big
bang, its cause was entirely physical insofar as it arose from
the larger multiverse. Moreover, if the multiverse as a whole
did not have a beginning, it would not require a temporal cause.
Thus is the kalām argument blocked -- again, if the multiverse
theory is correct. But why suppose it is correct? You might
think, with William Lane Craig, that “there’s no evidence that
such a world ensemble exists. Nobody knows if there even are
other parallel universes at all.” Indeed, you might agree with
Craig that even if there is such a multiverse, it wouldn’t
really undermine the kalām argument anyway, since (for reasons
he summarizes in the clip