Max Tegmark article on the cosmological necessity of parallel universes

[bascule]

Our office subscribes to Scientific American and I happened to notice an article by Max Tegmark on our bathroom floor:

 

http://www.sciam.com/article.cfm?articleID=000F1EDD-B48A-1E90-8EA5809EC5880000

 

He insists there are cosmological arguments which necessitate the existence of various types of parallel universes. One type he describes sounds less like a "parallel universe" and more like the necessary properties of a closed universe, however he describes what he calls a "Type II" universe which sounds more like the Everett many-worlds interpretation.

 

Can someone who actually studies this stuff opine?

[Martin]

Our office subscribes to Scientific American and I happened to notice an article by Max Tegmark on our bathroom floor:

 

http://www.sciam.com/article.cfm?articleID=000F1EDD-B48A-1E90-8EA5809EC5880000

 

He insists there are cosmological arguments which necessitate the existence of various types of parallel universes. One type he describes sounds less like a "parallel universe" and more like the necessary properties of a closed universe, however he describes what he calls a "Type II" universe which sounds more like the Everett many-worlds interpretation.

 

Can someone who actually studies this stuff opine?

[EDIT I am going to edit this simply to make the wording more polite.]

 

I thought SciAm the article was misleading. I felt that it fudged stuff to appeal to the imagination---mind candy.

I remember being disappointed by that article several years ago.

 

 

My impression is it had a number of logic holes or places where he used handwaving to lead to the desired conclusion. I chose one flaw and wrote him a polite letter about it. that was before his rise to FQXi celebrity in 2005.

 

He is really smart, really really charming, and he rides with waves fashionable ideas, where the grant and private foundation money is.

 

Tegmark (with his buddy Tony Aguirre) now heads the Foundational Questions (FQXi) branch of Templeton Money. they have done a lot of things that I think are fine, so maybe I should be grateful. They have given grants to people who are creative outsiders, who have something original going, and who deserve it----that the government wouldnt recognize.

 

that is good. But you don't get to be in charge of Templeton millions as a young guy unless you are a smooth operator and Tegmark is.

 

====================

The main tactic in that article is getting you to accept LEVEL ONE as a thin edge of the wedge, and then leading you on into more and more speculative realms.

 

LEVEL ONE is not even a real multiverse thing---it is just trivial arithmetic about large numbers. If the universe WERE spatially infinite then you could find arbitrarily large patches that repeat arbitrarily closely. Like somewhere in the decimal expansion of PI there is some place where it goes...123456789...just by randomness, and indeed unlimited number of such points.

 

BUT HE CONCEALS FROM THE READER RECENT EVIDENCE suggesting that the universe might not be spatially infinite but instead have a small measurable positive curvature, which completely destroys his Level One analysis.

WMAP3 data has made spatial finite more likely----one paper I saw had a confidence level of 65 percent for finite, but it's up in the air.

 

So what he did in the Sci Am is tendentious. Another scientist, in his place, might have acknowledged that the data do not make spatial infinite a certainty.

 

Then if you go along with his Level One then he will fly you on a fantasy ride into higher and higher levels of speculation. Until we have the MANY WORLDS INTERPRETATION of Quantum Mechanics with all the parallel possibilities in a GHOSTLY SANDWICH of you and all your different lives.

 

Many Worlds is a whole other story. the problems it was proposed (back around 1950?) to solve may have been solved by simpler means in more recent interpretations, making the somewhat Baroque invention of Everett less compelling.

The story is that Everett went to Copenhagen to talk to Bohr about it and Bohr scoffed and Everett dropped out of theoretical physics and took to designing weapons of mass destruction---later, like in the late 1950s? he started a computer company. Maybe you know. I've probably garbled the dates. Wikipedia would say.

The thing is Many Worlds Interpretation (MWI) is "multiverse" in a completely different sense from his Level One where there are similar parts of the universe actually over there if you go enough lightyears. they just strike the same emotional chord---the same spiritual resonance. People like to imagine having parallel but slightly different lives (in which they married that other girlfriend)

 

MWI should be excluded by Occam razor, IMHO, because it presupposes a huge unnecessary machinery of branching alternative existence. A huge mess of extra junk is assumed just to resolve certain puzzles which used to bother people ("collapse of the wave function"). AFAIK you can resolve the puzzles fine with much less junk. Rovelli's Relational QM seems to do it. It came along many decades later. And what is even more likely, I think, is that quantum mechanics itself will turn out to be not fundamental! It will be something that just emerges at level from something more basic, related to the nature underlying space, time and matter. And in the more fundamental theory, the PUZZLES THAT MOTIVATED EVERETT'S MWI WILL simply not exist.

so the whole business of these conflicting interpretations of quantum mechanics will be out the window.

 

Bascule that's just my personal take and I offer it with a free grain of salt:-)

I expect you have a different take altogether. You may like MWI and all that stuff, "eternal inflation" "bubble universes" etc.

 

thought I'd tell you my view on it anyway. Threw that old issue of SciAm in the recycle bin a long time ago:D

[bascule]

Wow, thanks for clearing things up. That's really sad to think about Tegmark: I routinely cite him in regard to his paper on the brain, in which he declares it should be interpreted as a classical, and not a quantum system. From what you've said it sounds like his credibility is less than stellar.

 

In terms of things I "like" (for purely arbitrary reasons) I prefer a closed spatial curvature. I didn't realize that Tegmark was suggesting an infinite repeating flat universe, in fact I just assumed that he meant if you proceed so far in closed space you will eventually get back to where you started... hence my confusion as to how that could be a "copy" of some object when really it's the same object. Anywho...

 

My preferred interpretation of waveform collapse was, for quite some time, Bohmian mechanics. I don't think they're realistic but for whatever arbitrary reasons I long for a non-local hidden variable theory.

 

The only "parallel universe" theory I personally entertain is Smolin's idea of fecund universes.

[Martin]

Now I am suffering from acute remorse. Tegmark is an excellent scientist, generally speaking. About the work you refer to---the brain, consciousness...---I havent seen it so I can't comment.

 

It's like he has two sides or two modes of operating. IIRC he was leader of one of those supernova Type IA teams that identified positive cosmo constant in 1998. That was firstrate work!

 

He is really tops, and he co-authors with Frank Wilczek. I just can't say it right. YOU HAVE TO WATCH OUT. The 2003 Sci Am article disappointed me because I have high expectations of him. So let me just take back in toto all the bad stuff I said about Tegmark and say that the situation is more complicated with him (even than it usually is with us all.)

 

Wow, thanks for clearing things up. That's really sad to think about Tegmark: I routinely cite him in regard to his paper on the brain, in which he declares it should be interpreted as a classical, and not a quantum system. From what you've said it sounds like his credibility is less than stellar.

 

In terms of things I "like" (for purely arbitrary reasons) I prefer a closed spatial curvature. I didn't realize that Tegmark was suggesting an infinite repeating flat universe, in fact I just assumed that he meant if you proceed so far in closed space you will eventually get back to where you started... hence my confusion as to how that could be a "copy" of some object when really it's the same object. Anywho...

 

My preferred interpretation of waveform collapse was, for quite some time, Bohmian mechanics. I don't think they're realistic but for whatever arbitrary reasons I long for a non-local hidden variable theory.

 

The only "parallel universe" theory I personally entertain is Smolin's idea of fecund universes.

 

Yes! that reproductive cosmology of Smolin would explain so much, and it is falsifiable by observation----just hasn't been falsified yet. Would be strange and so neat if it were correct!

 

Sorry about ranting like that about Tegmark, Bascule. Don't let my rant influence you. That Sci Am article just rubbed me wrong.

[bascule]

Now I am suffering from acute remorse. Tegmark is an excellent scientist, generally speaking. About the work you refer to---the brain, consciousness...---I havent seen it so I can't comment.

 

I'll start another thread on it...

 

He is really tops, and he co-authors with Frank Wilczek. I just can't say it right. YOU HAVE TO WATCH OUT.

 

Well, like most laymen I have a propensity to put too much faith in individual high-charisma scientists, mainly because I can't understand what they're actually talking about. Good thing science isn't charisma-based