The Multiverse, The Universe, and Everything

For those of us who are facinated by this sort of thing, there is an interesting layman's discussion on the theories of multiple universes in The Corner. Start here, and scroll up. It's just a discussion thread, but it is an interesting layman's discussion of the topic. As I'm not much of an expert on extreme physics, it was interesting to me.

Some interesting pieces:

What got this started:

PARALLEL UNIVERSES [Jonah Goldberg]
I'm not a big fan of them, though Spock looks great in a goatee. They never made much sense to me scientifcally and they seem like a crutch dramatically. Why is the parallel universe in various shows, including those unmentionable in the Corner, always so similar to the "normal" one? Why not transport into a universe where toasters eat clocks and we wear pants on our heads? Basically, in science fiction, parallel universes are a cheap ploy for the actors to play dress up and do something different with their characters. They're still preferable to the holodeck. But what isn't?

An explanation:

TWO, THREE, MANY UNIVERSES [Jonah Goldberg]

Lots of explanatory emails pouring in. This one is briefer and more lucid than most:

Mr. Goldberg;
I’m not even going to try to outmath Derbyshire, but there is simpler explanation of the concept of multiple universes.

1. The multiple Universes exist regardless of your conscious or unconscious decision to choose Bud Lite over Bud. Your selection does not create the Universe. Instead…
2. You only perceive the Universe you selected.

It’s akin to climbing a tree – all the branches in the tree exist before you start to climb, but your selection of which branches to climb determines your ultimate location in the tree.

So you did not create the moon and the stars by choosing your beer; instead, your choice of beer tells you which stars and moon you see.

The reason has to do with the concept of time. We perceive time as unidirectional. We can’t go back and undo a decision. If we could, we would have the ability to go back and explore the alternatives, and our memory would be cluttered with the paths we retreated from.

BTW, the movie “The Butterfly Effect” nibbles at the edge of this concept. The protagonist is capable of going back and undoing certain decisions and events. The movie is decent, and Ashton Kutchner does a decent job as the protagonist. BTW, those around him eventually perceive him as insane, because he can remember the paths that he retreated from.

A reference:

P.U.S CONT'D [Jonah Goldberg]

From a reader:

Jonah,
It's my understanding that the concept of parallel universes arose when physicist Richard Feynman came up with his concept of "sum of all histories" to help explain away the infinities that arose in his equations. I belive it was an attempt to "explain" the quantum physics weirdness of particles having a chance of behaving in ANY manner. Not just the normally expected ones. A particle could take any track in the equations, therefore, to observe all of it's behavior "everything" can happen (to the particles which make up you and I) in history.

And the concept of parallel universes have again risen in current String Theory. Seems that the current set of equations make (more)sense if there truely ARE parallel universes. There's even the idea that the Big Bang was an event where one of our parallel universes actually crashed into and "touched" our universe.

An excellent layman's description of this can be found on PBS's mini-series "The Elegant Universe".
http://www.pbs.org/wgbh/nova/elegant/

And a critique:

RE: MANY UNIVERSES [John Derbyshire]
My private opinion, Jonah, is that the "many worlds interpretations" (MWIs) of quantum physics--there are at least three--are total crocks.

Martin Gardner is of the same mind. He skewered the MWIs in an essay in Skeptical Inquirer magazine four or five years ago. The article (and a response to critics of it) is printed in Martin's 2003 book Are Universes Thicker than Blackberries? (NB: The book title refers to the fruit, not the gadget.) Martin's conclusion:

The stark truth is that there is not the slightest shred of reliable evidence that there is any universe other than the one we are in. No multiverse theory has so far provided a prediction that can be tested. ... Surely the conjecture that there is just one universe and its Creator is infinitely simpler and easier to believe than that there are countless billions upon billions of worlds, constantly increasing in number and created by nobody. I can only marvel at the low state to which today's philosophy of science has fallen.

And for those of you who could scarcely care less:

WAIT A MINUTE [John Podhoretz]
When I joined the Corner, I wasn't told there would be math.

If anything interesting comes later, I'll add to the quotes...

P.S.: Sorry for the depressing tone of Friday's Furo Questus. I promise to be a little more careful with my grumpy, depressed, and sleep-deprived writings.