Tuesday, July 22, 2014

Many Worlds Are Called, but Only One Is Chosen

In a blog post entitled “Why the Many-Worlds Interpretation of Quantum Mechanics Is Probably Correct,” Sean Carroll explains his strong belief in Hugh Everett III’s theory. It’s obvious that this universe results from a series of events, almost all of which could have produced some other outcome. So, there must be many, many possible universes, maybe not an infinite number, but a lot. Why this universe? Do all of these possible universes exist? The physicist Hugh Everett III thought that they do.

Experiment tells us that the universe is governed by quantum mechanics. If a system can be in one of a number of states, quantum mechanics says it’s in all of the states at once until it’s observed, and then it will be found to be in one and only one of the states, a phenomenon called collapse of the wave function. However, this doesn’t mean it was “really” in that state all along. If you repeat the experiment you will likely find that the system is in a different state. Physicists aren’t comfortable with this because they can’t figure out how the choice of state is made. They mostly just accept that that’s the way nature is.
Everett didn’t accept it. His “many worlds” theory says that whenever such a system is observed, all of the possible states are observed, but each one in a different universe. Thus there are many, many worlds, not just this one in which we observe one outcome and only one. Everett’s interpretation is a neat resolution of the original conceptual problem of what makes the wave function suddenly collapse, but unless you can find some reason why only one of these worlds is real, you’re stuck believing that they all exist, which is another huge conceptual problem. Quantum mechanically, an observer outside of the collection of worlds could collapse this wave function by making an observation. But how can there be an observer—or anything—outside the universe? In my last post I showed how atemporal existence, or God, creates everything by observing itself. This implies that one and only one universe exists, as I’ll show next. The rest of Everett’s universes are virtual, not real. If you haven’t read my last post, read it now.

In Everett’s many worlds zoo, there’s a lot of similarity between older universes and their offspring.  Some universes are more fecund, that is, they contain more conscious beings like us. Conscious beings make choices and so these universes produce copious numbers of offspring like themselves. After a while the population of possible universes is dominated by universes that contain a maximal number of conscious beings. Not only are these universes maximally fecund, but they are also maximally diverse for similar reasons. In observing itself, existence or God must almost certainly see one of these complex universes. Now, God only gets one look and that’s it. That’s what exists. That’s our universe. It’s maximally fecund and maximally diverse. Hugh Everett figured out how quantum mechanics is the reason why there’s a huge population of possible universes, but he didn’t know that God gets to pick only one.
And now, if you read my last post you should understand the principle of complementarity, and you might ask why this principle wouldn’t allow God to observe all of the possible universes. The reason is that complementarity doesn’t allow you to see all aspects at once, just one at a time, and God, being atemporal, doesn’t experience time. “Ah,” you say, “but if it’s OK with complementarity for God to see our universe through all of our eyes at once, because we’re different observers, why wouldn’t the temporal observers in those other universes qualify as different observers, allowing God to see those universes, too?” “Aha,” I reply, “that’s because all those other universes overlap with ours before they split off, so those are not completely different observers and they don’t qualify.”.  

That brings up another question. Am I saying that God had no choice in creating the universe? If God has no free will, how can anyone else? The “anyone else” part is easy. We are piles of molecules. There’s no way we can have free will. The atemporal “I” (i.e., God)  might have it, but our temporal “I” certainly doesn’t. In the case of God, there’s no way to tell. Any quantum mechanical choice might or might not be God exercising free will. We don’t know and probably never will.
A word of caution: it’s important not to make the mistake of thinking that once the choice is made, the temporal universe is deterministic. That’s trying to see temporal and atemporal simultaneously, which violates the principle of complementarity. We’re not allowed to ask a question like that.

We can think of this universe as a giant theatrical production. All those possible universes are like scripts, only one of which gets produced. We are the characters—makeup, costumes, and some lines in the script. Each character has a different script within the overall script, and these scripts can be incompatible, but that’s not a problem because each character’s script is seen by only one observer. The composite script basically writes itself as the population of possible universes is built up quantum mechanically. You could say that existence self-organizes. In As You Like It, William Shakespeare wrote, “All the world’s a stage, and all the men and women merely players.” He was almost right. We’re merely characters. There’s only one player—existence.