Into what is the universe expanding?

Our universe
is all of space-time,
and space-time
is all of our universe.
Our language,
with the possible exception of mathematics,
is rooted in space-time,
and we have
no language
for that-which-is-not-space-time.
There is no what
that the universe is expanding into
because what,
and when
are properties of space-time,
not that-which-is-not-space-time.

So where does that leave us?

it leaves us with Wittgenstein:
What can be said at all
can be said clearly,
and what we cannot talk about
we must pass over
in silence.

From a submission by Jim Ford of Watford to the Guardian’s Notes and Queries column, 13th April 2011. Submitted by Ailsa Holland.