  The main mystery of quantum mechanics is contained in Wheeler's delayed
choice experiment, which shows that the past is determined by our choice of
what quantum property to observe. This gives the observer a participatory role
in deciding the past history of the universe. Wheeler extended this
participatory role to the emergence of the physical laws ("law without law").
Since what we know about the universe comes in yes/no answers to our
interrogations, this led him to the idea of "it from bit" (which includes the
participatory role of the observer as a key component).
  The yes/no answers to our observations ("bit") should always be compatible
with the existence of at least a possible reality - a global solution ("it") of
the Schrodinger equation. I argue that there is in fact an interplay between
"it" and "bit". The requirement of global consistency leads to apparently
acausal and nonlocal behavior, explaining the weirdness of quantum phenomena.
  As an interpretation of Wheeler's "it from bit" and "law without law", I
discuss the possibility that the universe is mathematical, and that there is a
"mother of all possible worlds" - named the "Axiom Zero".
