(A short rant for a Friday)
If you’re like me, you learned the following story.
The universe, or cosmos, consists of a four-dimensional space-time continuum which contains matter and energy. It all began with a big bang singularity: time as well as space started then, so it doesn’t make sense to ask what happened “before”. The universe probably extends beyond what is observable, but the same physical laws prevail everywhere. Nothing exists outside the universe.
Every statement in that paragraph is likely wrong.
1. Space-time is probably not continuous; in fact, space-time may not be fundamentally distinct from matter-energy.
2. We don’t have a quantum gravity theory yet, but any version will likely banish the big bang singularity. Our universe almost certainly arose from a pre-existing context.
3. Observable physical constants appear fixed, but this has been questioned in some cases; we have no good reason to think physical laws are fixed beyond what we can observe.
4. According to many proposals multiple universes exist. And if they do, there’s no good conceptual reason to think they are entirely isolated from each other (just because we appear causally isolated from our point of view).
I think trends in cosmological and physical theories lend support to a different picture. What we think of as the actual world is just a local neighborhood in a larger expanse. And I can see no non-arbitrary reason to think this larger reality is anything short of being a realm of maximal size. The maximal size is the one which encompasses all metaphysical (=logical) possibilities.