Posted on 09/23/2008 3:14:32 PM PDT by LibWhacker
Three different trends in physics each suggest that our universe is just one of many.
We usually think of the universe as being “everything there is.” But many astronomers and physicists now suspect that the universe we observe is just a small part of an unbelievably larger and richer cosmic structure, often called the “multiverse.” This mind-bending notion – that our universe may be just one of many, perhaps an infinite number, of real, physical universes – was front and center at a three-day conference entitled "A Debate in Cosmology — The Multiverse," held at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, earlier this month.
The multiverse idea is not new. Physicists have been toying with it ever since Hugh Everett III came up with the “many worlds” interpretation of quantum mechanics back in the 1950s. It took on new life after 1980, when the inflationary-universe theory of the Big Bang's first moments began to suggest that our Big Bang was not a unique event but just a tiny bit of a much larger, ongoing process.
The multiverse idea has had yet another surge of interest in recent years, as a result of a newer idea: string theory. Developed as a possible “theory of everything” that would unite quantum mechanics and gravity, string theory, physicists hoped, would provide a unique description of the universe and why the laws of nature are what they are. Instead, according to some theorists, it lays out a picture of not a single universe but rather a broader “landscape” in which the laws of physics vary from one region to another. It may be that only a small fraction of these regions have conditions allowing any kind of complex matter to exist, and hence intelligent life.
Part of the appeal is that a varied multiverse like this would neatly account for the many remarkable coincidences we observe in the laws of physics that make possible any kind of complex matter, such as atoms and molecules. When we life forms arise and look around, we naturally find ourselves in one of these very rare special realms, merely because we could not have come into being anywhere else. This kind self-selection logic is called "anthropic reasoning."
Equations Meet Philosophy
The lead-off speaker at the conference was Paul Davies of Arizona State University, a prolific writer on cosmology and philosophy. He noted that the multiverse idea has been “propelled to fame” in the last decade or so by the string-theory landscape idea – the notion “that maybe the laws of physics are not absolute, fixed, universal, immutable mathematical relationships,” but instead might be “more like local bylaws.”
Several other speakers, including Laura Mersini-Houghton of the University of North Carolina, echoed that view. The idea of multiple universes “did not go down very well with scientists” when it was first put forward, she said in an interview, but now “there’s an explosion of interest in the subject… because of the discovery of the ‘landscape’ of string theory.”
Along with string theory and many-worlds quantum mechanics, a third motivation for taking the multiverse seriously comes from current ideas on Big Bang inflation. In a version known as “eternal inflation,” there are endless, ongoing big bangs breaking off from an underlying substrate of inflating space-time. Each one produces its own separate cosmos.
However, it's not at all clear how these different kinds of multiverses – grounded in quite different physical theories – may be related to one another. Still, the fact that three different lines of reasoning, all rooted in modern physics, seem to be pointing the same way makes some feel there must be a connection. “My gut feeling is that these multiverses have to be related,” said Mersini-Houghton.
David Albert, a former physicist who now teaches philosophy at Columbia Universiy, says he has more confidence in the Everett many-worlds interpretation of quantum mechanics than in the landscape of string theory. “In the Everett case, at least we have a clear formulation of what the claim is,” he said. “In these other views, the talk is still at a stage that’s much more amorphous…. This kind of meeting is a useful way to begin to sit down and think through those questions more clearly.”
With fewer than 20 scientists taking part in the conference, the talks often gave way to lively debate, with audience members challenging speakers on specific points or calling for more detail or clarification.
Albert was not the only philosopher at the meeting. One of the most interesting presentations was given by Hilary Greaves of Oxford, who discussed philosophical problems with many-worlds quantum theory. (In a nutshell: Conventional quantum theory gives the probability that each micro-event will happen, but offers no clue as to why it actually does or doesn't, leaving spooky conundrums. In the many-worlds view, every possible outcome happens with 100% probability, somewhere among the alternative universes, leaving no spookiness but giving no explanation of where these universes are. Each interpretation matches the real world equally well; you just choose which paradox to accept.)
Greaves is concerned that in the many worlds view, the probabilities have "disappeared," a notion which is hard to reconcile with traditional approaches to quantum theory. She and her colleagues have developed a particular strategy for tackling the many-worlds question, based on a field of mathematics known as “decision theory.” Her talk clearly gave the physicists in the audience much to think about.
Many scientists look down on philosophy as mere question-posing and guesswork. But philosophy seems impossible to avoid when discussing certain problems in physics, especially those dealing with fundamental aspects of reality, such as cosmology and particle physics. In his entertaining talk, Davies referred to the old Hindu story of the Earth resting on the backs of four elephants, which in turn stand on a giant turtle. One is then faced with the question of what the turtle stands on. Perhaps there is some kind of ultimate explanation down below, a Prime Cause – some kind of “super-turtle” that brings the chain of explanation to an end.
For many physicists, Davies said, the laws of physics themselves have served as such an explanation. But this view becomes problematic if the laws themselves change over time, or vary from region to region. Alternatively, there may simply be no ultimate explanation, he suggested, in which case one must accept an infinite regression of causes — "turtles all the way down.”
Not everyone is ready to embrace the idea of the multiverse. At one point, Perimeter Institute physicist John Moffat – known for his work on general relativity, Einstein’s theory of gravity – told the audience that the idea of multiple universes “has come up often in science fiction – and that’s where it belongs.” Imagining unseen universes “is not the kind of science we’ve been doing since Galileo,” he said.
Several presenters addressed whether the idea of the multiverse can ever be subjected to experimental testing. Lee Smolin, also from Perimeter, said that in certain versions of the multiverse picture, one could indeed make testable predictions. (Smolin supports an intriguing model in which black holes in one universe can give rise to new universes elsewhere, an idea he describes in his book The Life of the Cosmos.)
There was one “celebrity scientist” on hand – Columbia University physicist Brian Greene, author of The Elegant Universe and The Fabric of the Cosmos. Greene did not give a scientific talk at the conference, but he did deliver an engaging public lecture based on his new book: a children’s story called Icarus at the Edge of Time.
oh yeah? infinity plus one!
"Guess" is not data. They can believe what they want. But once they venture into the belief territory they will be rightly ridiculed for criticizing other people for the simple act of believing.
And I believe if you are being left behind, it is due to your own choice.
I don’t view it as “one of many”.
Rather, I see it as “layers”. A quantum layer. A relativistic layer. Others.
No “layer” can contradict another “layer”, so as long as they are in agreement, everythings hunky dory.
"Guess" is not data. They can believe what they want. But once they venture into the belief territory they will be rightly ridiculed for criticizing other people for the simple act of believing.
And I believe if you are being left behind, it is due to your own choice.
Absolutely! Interesting topic!
Imagine that.....
Since everything will be destroyed in this way, what kind of people ought you to be? You ought to live holy and godly lives as you look forward to the day of God and speed its coming. That day will bring about the destruction of the heavens by fire, and the elements will melt in the heat. But in keeping with his promise we are looking forward to a new heaven and a new earth, the home of righteousness.
Scripture has a lot to say about a new order of things; a new heaven and new earth.
Looks like science is just catching up..... again....
The TV show "Sliders"(from one concurrent universe to another) was either beyond its time or to early for it..
It appears Americans are getting stupider.. and the Sliders meme window is closed.. Quantum mechanics work on cars these days..
That "possibility" (of multiverses) certainly simplifies choice. It will not matter. For instance, I encourage all Obama supporters to not vote since Obama will win, somewhere. Maybe even here since seeing that the Obama supporters might have something up their sleeves, the McCain supporters will also not vote. But then this might be the multiverse where the necessary molecules just happen to gather in one spot and form Ronald Reagan again and seeing this event occur the single voter in each state will write in Ronald Reagan and he will be the President again. Ah, but he must be reformed within the territory of the United States to be eligible.
But then again, this may be the multiverse in which some clever scientist proves that there are not multiverses.
etc.
etc.
Ad infinitum. Does the list of all lists that do not contain their own names contain its own name? ala K. Göedel
You’re out there dude.. ( cleaning glasses)...
Thanks for the ping!
If one accepts the axiom that the conditions for each system are fundamentally different, then there can be nothing in this realm that can be analogous to the others. Hence his conclusion is nonsense.
“I don’t want to be left behind. “
Mock if you wish. Your eyes will be opened soon enough. Unfortunately, it may be too late.
You are on the side of an evil god? Am I to believe in a god of love and a god of forgiveness, or am I to believe in a petty, jealous, torturing god? If your god is a torturing god, then I am better than it. Does lowering myself to its level make me better or worse?
“If your god is a torturing god, then I am better than it”
Based on what criteria?
If I do not accept Jesus as Lord, I will be tortured for all eternity. I can't help it if I can't believe something. I'm not evil. I just can't believe in invisible people. Your god would torture me forever. I wouldn't treat a dog that way.
“If I do not accept Jesus as Lord, I will be tortured for all eternity. I can’t help it if I can’t believe something. I’m not evil. I just can’t believe in invisible people. Your god would torture me forever. I wouldn’t treat a dog that way.”
I figured you meant in terms of compassion, but the clarification was needed given the ambiguity. I know you don’t believe, but assume for the sake of argument that He exists. In what way are you better? Certainly not knowledge, power, or a host of other attributes, so that’s why I was asking what criteria you were using when you asserted that you were better than the Christian deity.
BTW, what is your field? I see no reason why someone who has a very logical brain can’t be a believer. I’m a mathematician and have no problem believing. In fact, I know a number of other religious mathematicians (though many keep this side of themselves pretty quiet). On the other hand, I don’t know very many religious physicists (in the closet or not). My hunch has always been that this is a result of the difference of method between the two areas.
I am kinder. I am more forgiving. I understand why some people can't believe in things without evidence. I wouldn't torture Osama Bin Laden out of vengence. Not for a minute, not for an hour, and certainly not for all eternity. Don't get me wrong, I would kill him with my own hands. I just wouldn't torture him.
“I wouldn’t torture Osama Bin Laden out of vengence.”
I wish I could say that I wouldn’t either. but I’m honestly not so sure.
Also, just to be clear, I was getting on you for making a rather rude comment about the rapture, not your position on this article. I really have no interest in the “how” God did it aspect of the debate, so I don’t waste my time on the evolution threads.
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