Max Tegmark’s Multiverse Thursday, Jan 18 2007
anthropics 2:42 pm
This posting is just for those who hadn’t yet seen it. Max Tegmark views our universe as one among many possible mathematical structures, and he believes that all mathematical stuctures are indeed manifested physically, though only a minority contain observers to testify to their existence. His Multiverse FAQ can be found here. Tegmark’s conclusions have big anthropic implications, the likes of which we’re only just beginning to unravel. He also wrote a paper on why anthropic considerations force all intelligent observers into universes with three space dimensions and one time dimension.
- Does anyone have a mathematical statement of the horizon problem? I have yet to see one anywhere.
- Ergotic? The only references I can find to this deal with the fungus ergot, which clearly has nothing to do with the multiverse.
- Different “initial conditions”? Why should regions of the universe have different initial conditions? They all started from the same origin in the same manner and the same laws of physics, didn’t they? No, we don’t have any way of discovering this experimentally, but it’s the simplest assumption consistent with what we know.
- A lot of the new quantum mechanics theories seem to be indistinguishable from neat mathematical toys; even something as prominent as string theory has no actual experimental evidence I’ve heard about.
- “Unreasonable effectiveness of math in physics”? Any numerical quantity can be described with math. Even if it’s totally random, like some quantum events, we can still write out equations explaining why it’s totally random and how we can modify the experiment to be not random. So this is really “unreasonable effectiveness of numbers in physics”, and anyone who can coherently describe exactly why physics is describable with numbers would probably win the Nobel Prize for metaphysics, if one existed.
Tom, instead of “ergotic”, I think it should be “ERGODIC”, which, in the context, makes more sense. See if that doesn’t resolve the quandary…
>>”A lot of the new quantum mechanics theories seem to be indistinguishable from neat mathematical toys; even something as prominent as string theory has no actual experimental evidence I’ve heard about.”
It truncated my post!!! String and Brane theory may still be viable, but falsifiable, corraboratable propositions need to be generated by Brane theorists, and we ain’t got any (yet, anyway); and w/o that [experimental results], it’s little more than “pretty math”… See Lee Smolin, *The Trouble With Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next* and Peter Woit, *Not Even Wrong: The Failure of String Theory And the Search for Unity in Physical Law*
But see also, Alex Vilenkin, *Many Worlds in One: The Search for Other Universes* for lucid exposition of the position(s) of Tegmark, Andrei Linde, Larry Sussman, et al.
I think one of the interesting consequences of the assumption that there are an infinite number of universes with an infinite amount of duplication of arrangements of matter, specifically an infinite number of exact duplicates of myself in this same context, is that everything is ultimately meaningless. Or at least meaningless by human standards.
Think about it. In such a circumstance, every decision you’ve ever sweated happens all possible ways with infinite duplication. Since the proportion of good and evil acts, by our definitions, never changes in such a multiverse, the idea of increasing the good or increasing the evil doesn’t work.
Not really directly relevent to Tegmark’s work but interesting to think about.
“Daddy, why do bad things happen to good people?”
Best answer I’ve ever heard.
[...] 1 – Max Tegmark’s Multiverse “Max Tegmark views our universe as one among many possible mathematical structures, and he believes that all mathematical stuctures are indeed manifested physically, though only a minority contain observers to testify to their existence.” (tags: theory thinking quantum mathematics cosmology reality multiverse universe physics science) [...]
Many worlds? OK? How many? A finite number of them? Aleph0? Aleph107? More than any aleph?
Do all worlds have the same number of parallel worlds?
If not, is there a parallel world with 0 parallel worlds?
If yes, when one additional created, everything is adjusted everywhere in a minute, even much less?
Something fishy, just like SETI. Eve more.
Think about again.
“Many worlds? OK? How many? A finite number of them?”
According to our current theories of the universe, a countably infinite number (Aleph-0). Space time is 4D, so if it extends infinitely far in every direction, than the total number of worlds is infinity^4 = infinity.
“If yes, when one additional created, everything is adjusted everywhere in a minute, even much less?”
One of the neat things about infinity is you can add one more world without the infinity increasing in number or even noticing. See http://en.wikipedia.org/wiki/Hilbert's_Hotel.
An infinite complexity, just to explain a finite size problem, is a godlike solution.
I don’t like that. I don’t like infinity at all.
“I don’t like that. I don’t like infinity at all.”
Unfortunately, “I don’t like it” isn’t a valid objection to a scientific theory. I don’t like the Second Law of Thermodynamics, but it’s there.
Fishy this, fishy that, nature doesn’t care… and neither do professional physicists whose opinion matters much more than any of ours.
Facts matters, not opinions.
If the “opinions of (various) professionals” matters so much to you… close this blog, Michael.
Some arguments against Greek gods, angels, aliens … work quite well against this multiple world construction as well.
I am glad, we have only aleph0 of them, so the majority is canceled already.
The whole ontology of “possible worlds” is still rather hotly debated. Modal realists (such as the late David Lewis, certainly one of the most vivid intellects in this field, along with Bob Stalnaker, and a few others) do indeed maintain that possible worlds describe (and indeed denote) real realms, albeit rather apart from our own. And, of course, Everett’s “relative state” interpretation of the basic math of quantum theory (aka the many worlds model) dovetails with such an ontology in a rather interesting way. And Thomas’s invocation of Occam’s Razor (with which I nonetheless empathize, mind you) notwithstanding, supporters of Everett’s interpretation (and the many variations that’ve sprung up since) maintain that this is ultimately the only way to make sense, not only of the mathematics involved, but of such empirical/experimental results as the double-slit experiment (see, for instance, Dave Deutsch’s discussion in his *Fabric of Reality*). What we need is a good (meta)model or (meta)theory of **hyperspace**, which is what both Jack Sarfati and Saul-Paul Sirag have been working on for many years now. But, of course, it would HELP, if they had a well-worked out background theory, whether it be Brane theory or Loop Quantum Gravity (which some claim are integrateable anyway), **which is also experimentally-corraborated**. What we need, perhaps, is for Saul-Paul to get together with both Ed Witten and Lee Smolin (and maybe also Peter Woit), then they might be able to brainstorm a breakthrough…(stay tuned)
Speaking about the double slit experiment … I’ve never understood, why the Hell, no effect is there EVEN BEFORE we emit an electron. Our parallel neighbours alway start at the moment we do? Never earlier?
Bad theory is worse than no theory. As a bad mine field plan is worse than none at all.
I think it is important to get beyond the hypothesis that every mathematical structure is realized. What we really want is to find some particular structure that has a unique claim to existence.
I make an attempt over at http://www.towardsrationalexplanationexistence.blogspot.com/
What do you think?
I have a problem with the idea that everything is math, actually. I do not see how to get qualia–for example the greeness of green–from mere mathematical structure…