  It is fair to say that the deepest mystery in our understanding of nature is
the birth of our universe. Much of the dilemma over the last decades comes from
the extraordinarily small probability that the universe started with the high
energy Big Bang as compared to the chance of nucleating any other event. How
can Big Bang cosmology be $10^{10^{123}}$ times less likely than nucleating the
present cold universe, while accumulating such exquisite agreement with
astrophysical data? Why don't we see the other nucleations that, if left to
chance, seem to overwhelmingly outnumber us? Here I discuss the point of view
that the selection of the initial conditions can be meaningfully addressed only
within the framework of the multiverse and that the reason why Big Bang
inflation was preferred over other events lies in the quantum dynamics of the
landscape of the initial patches. The out-of-equilibrium dynamics selected the
'survivor' universes be born at high energies and the 'terminal' universes at
low energies. I briefly review the testable predictions of this theory, in
particular the giant void observed in 2007. The second part focuses on the
extended framework, in particular a set of postulates needed for defining the
multiverse.
