When I was in grade school, fifth grade, I think, one of my teachers assigned an essay, "Why is there something rather than nothing?". An interesting question. Basically, my explanation was that we wouldn't be here to see it if there were nothing, and that's why there's something. It took me front and back on two sheets of paper to get that idea across -- discussions of alternative universes and such -- and I think I did an OK job of it, but it left me unsatisfied. Somehow the explanation lacked a certain something -- like an answer to the question! I think I got an "A" on it, but I never stopped wondering if I could do a better job.
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This explanation of why there is something rather than nothing, or of why the universe is the way it is -- "because if it weren't here we wouldn't be here to see it" -- is troubling because it doesn't deal with how very improbable the universe is. Isn't it improbable that a universe as complex and diverse as ours could simply come about on its own? Sherlock Holmes is famous for saying, "when you have eliminated the impossible whatever remains, however improbable, must be the truth."1 Even so, the explanation falls short.
What's needed is an explanation that takes into account the improbability of our universe having just formed out of thin ether. And I think I have one, now. In this page I'll bring you on a journey of imagination (a journey you may have already traveled, so it will be familiar to you, I hope). We will imagine not just one universe but many. Not just many, but incredibly many universes. And you will imagine how they're all related to one another, and how you find yourself in this one. You'll see that some universes are more special than others, and the most special of all is the one you're in. Once you're able to imagine all this, I think you'll agree that of all the gazillions of universes, it's highly improbable that you should find yourself in this one. Yet here you are! (See "puddle").
Let's start down that road of imagination...
Once upon a time (when I was in College), I took a course in compiler design in which I learned all about Finite Automata. A Finite Automaton is a machine that accepts input and enters states as each new input symbol is read based in the previous state and the input symbol. It's a useful model for designing a lexical analyzer for a compiler. A Deterministic Finite Automaton is one where each new symbol and the previous state uniquely determine one new state. A Non-Deterministic Finite Automaton is one where many new states can be entered all at once. That sounds tricky, but actually you can define a whole new set of states which are the set of subsets of the original set of states. Thus a Non-Deterministic Finite Automaton is identical to a Deterministic Finite Automaton with the appropriate re-mapping of states.3
If I lost you during the previous paragraph, just imagine the Non-Deterministic Finite Automaton enters a set of states after reading each new symbol instead of just a state. In other words, it consists of many different automatons all at once -- like parallel universes. That's interesting! Many universes existing side by side all at once are to a single universe as a Non-Deterministic Finite Automaton is to a Deterministic Finite Automaton. But what in the universe is analogous to the automaton's sequence of input symbols? Hmm. Give me some time to think about that! (Maybe time is the answer!)
In computers, many programs (or processes) exist and operate side-by side, and each "sees" its own copy of memory, as well as some shared memory. In a way, this is just like the concept of parallel universes -- they exist side by side without knowing about each other. This is useful in multi-tasking systems to give each program the appearance of having a whole computer at its disposal. It's also useful for recursive algorithms such as the Recursive Sort, which works like this: If there's one item to sort, you're done; it's sorted. Otherwise, sort the first half of the list, sort the second half, and merge the two lists, and you're done. You'll notice that Sort invokes Sort -- that's what recursive means: a program that invokes itself. Actually, it doesn't invoke itself but rather a copy of itself. And all the copies of the Sort program don't know or care about each other because they exist in parallel universes!
In UNIX terminology, if I may, a process may "Fork". That is, where there was just one process previously, now there are two. Each process inherits a copy of the single environment that existed before it was created, and the new processes need not know about their twin. The use of the word "Fork" brings to mind a traveler who comes to a fork in the road. Instead of having the traveler take the left or right branch, he can make an identical copy of himself, and send each copy down one branch.
Over the years, I've read some things about the "Time Travel Paradox" in which the apparent paradox is resolved by imagining that the time traveler lands in a parallel universe -- perhaps one split off (forked) from the original universe by the act of time travel. So when he makes changes to "the past" he doesn't affect the universe he came from but only the universe in which he arrived.
Recently, an article on The Strange Properties of Psychokinesis4 was brought to my attention. Here, the author, Helmut Schmidt, points out that quantum events have a duality in which two possible outcomes exist simultaneously until an effort is made to detect which outcome occurred. At that moment of detection, and not before, the die is cast, and the outcome -- one way or the other -- becomes fact.
According to Webster, the word quantum means any of the very small increments or parcels into which many forms of energy are subdivided or the small subdivisions of a quantized physical magnitude. Webster doesn't say that quantum increments are atomic, or indivisible, but I think they are. Beyond that, I don't have much understanding of quantum mechanics, and it's a good thing, I suspect, because if I knew anything about the subject I would have probably dismissed The Strange Properties of Psychokinesis as garbage that is based on a faulty understanding of quantum mechanics, and not read it. But I did read it. In case you don't want to read it right now, I'll tell you that basically the article says that while the duality exists -- after a quantum event but before an effort has been made to detect the outcome -- a human being has the ability to choose one outcome or the other.
As I was reading Mr. Schmidt's article, it occurred to me that a quantum event might fork the universe, and that the duality exists in the sense that both outcomes exist, each in its own copy of the universe, and that these universes continue to move forward independently of one another.
Let's accept that all events are composed of atomic quanta -- that is, that they can be broken down to simpler and simpler events until you reach the simplest event that can not be broken down any further. Also, let's accept -- just for discussion -- that every quantum event forks the universe.
Can you imagine that? Every second there are billions of trillions of zillions of quantum events somewhere in the universe. And each one forks the whole universe. And you're sitting on that forked road -- no not a road, exactly, more like a water slide at Hurricane Harbor, where you're being pushed past fork after fork by the water of time. But at each fork, instead of making a decision, the whole water slide is replicated with a copy of you sliding down each possible path!
My daughter Meghan, when she sees a person who impresses her, says "I want to be her when I grow up". Well, Meghan, you can't be her. The die is cast. You are you, and she is her. In the same way, you can't chose which path you'll follow. You'll follow both paths -- one in each universe. After the event occurs, and the universe forks, you can say which path was followed in your universe. What you consider you is now just the one copy of you in your universe. You can take some comfort, perhaps, in knowing the other path was followed in that other universe.
I appreciate your accepting that all events fork the universe. I know it's not easy to imagine, but it's a self-consistent world we're imagining, isn't it? I don't see any paradoxes looming, do you?
OK, then. Cast your imagination back to the first fork in the road. A universe exists, but with nothing in it -- nothing except amorphous energy, perhaps. The first quantum event is about to happen: the spontaneous creation of a pair of particles. On one path, we have a universe that still has nothing in it, while on the other we have a universe with two particles. In this universe, another quantum event happens -- more spontaneous particles are created, then another and another. Now the universe has forked a billion trillion zillion times. In some of the universes there are zillions of particles, while in others there are just a few particles. This process continues until in one of the universes enough particles have spontaneously appeared to make a "big bang". This is the universe we're descended from. "The rest is history," as they say.
Can the paths of this forked road ever join together? Are all forks choices in which the universes diverge? Or can two universes ever join together at a reverse-fork? I say they can and do join, but only if they're absolutely identical at the time of joining.
What is time? I'm going to do some thinking on this matter. And some reading. I read in Science News about a book by Huw Price called Time's Arrow & Archimedes' Point : New Directions for the Physics of Time2. So I ordered it from Amazon.Com. I started reading the book, and find it very interesting. (Click here to see what I've learend so far.) After I finish reading the book I'll write down any brainstorms right here on this web site.
Is there any meaning to the existence of parallel universes as I've described them here? All along, I've been putting forward ideas, and you've been reading them. But is any of it meaningful? That is, can any meaning be ascribed to thinking about parallel universes if these parallel universes can't affect our universe? If there is no meaning then I have some good news and some bad news: The good news is that it doesn't "cost" anything to believe in it because the meaningless belief can't violate any meaningful beliefs. The bad news is it doesn't "give us" anything, because it can't support an argument that leads to any meaningful conclusion. To search for meaning in this discussion, I would urge you to consider whether it helps to solve the "improbability" problem that I posed, above.
1. Sir Arthur Conan Doyle, The Hound of the Baskervilles, Berkley Pub Group; ISBN: 0425104052
2. Huw Price, Time's Arrow & Archimedes' Point : New Directions for the Physics of Time. Oxford Univ. Pr (Trade); ISBN: 0195117980
3. The text for this college course was Alfred V. Aho, Jeffrey D. Ullman, Principles of Compiler Design. Out of print; ASIN: 0201000229
4. Helmut Schmidt, The Strange Properties of Psychokinesis