How to Understand the Universe When You’re Stuck Inside of It
Philip Cheung
Philip Cheung
Quote:You have a slogan: “The first principle of cosmology must be: There is nothing outside the universe.”
In different formulations of the laws of physics, like Newtonian mechanics or quantum mechanics, there is background structure — structure which has to be specified and is fixed. It’s not subject to evolution, it’s not influenced by anything that happens. It’s structure outside the system being modeled. It’s the framework on which we hang observables — the observer, a clock and so forth. The statement that there’s nothing outside the universe — there’s no observer outside the universe — implies that we need a formulation of physics without background structure. All the theories of physics we have, in one way or another, apply only to subsystems of the universe. They don’t apply to the universe as a whole, because they require this background structure...
Quote:You’ve recently proposed such a theory — one in which, as you put it, “the history of the universe is constituted of different views of itself.” What does that mean?
It’s a theory about processes, about the sequences and causal relations among things that happen, not the inherent properties of things that are. The fundamental ingredient is what we call an “event.” Events are things that happen at a single place and time; at each event there’s some momentum, energy, charge or other various physical quantity that’s measurable. The event has relations with the rest of the universe, and that set of relations constitutes its “view” of the universe. Rather than describing an isolated system in terms of things that are measured from the outside, we’re taking the universe as constituted of relations among events. The idea is to try to reformulate physics in terms of these views from the inside, what it looks like from inside the universe.
Quote:I know from your book that you’re a realist at heart — you believe strongly in a reality independent of our knowledge of it — and therefore, like Einstein, you think quantum mechanics is incomplete. Does this theory of views help complete what you think is missing in quantum theory?
Einstein — as well as someone called Leslie Ballentine — advocated an “ensemble interpretation” of the wave function [the mathematical object that represents a quantum system]. The idea was that the wave function describes an ensemble of possible states. But one day, I was sitting in a cafe working and suddenly I thought: What if the ensemble is real? What if, when you have a wave function describing a single water molecule, it’s actually describing the ensemble of every water molecule in the universe?
So whereas normally we would think that there’s one water molecule but an uncertainty of states, you’re saying that the uncertainty of states is actually the ensemble of all the water molecules in the universe?
Yes. They form an ensemble because they have very similar views. They all interact with one another, because the probability of interaction is determined by the similarity of views, not necessarily their proximity in space.
'Historically, we may regard materialism as a system of dogma set up to combat orthodox dogma...Accordingly we find that, as ancient orthodoxies disintegrate, materialism more and more gives way to scepticism.'
- Bertrand Russell
- Bertrand Russell