A REASONABLE CASE

A discussion about religion, reality and reason
EXPLANATION FOUR: UNIVERSALITY IN MANY-WORLDS: HAVING YOUR CAKE AND EATING IT TOO.
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EXPLANATION FOUR: UNIVERSALITY IN MANY-WORLDS: HAVING YOUR CAKE AND EATING IT TOO.
3rd Aug 2014, 3:46 PM
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Author Notes:
alschroeder
Continuing down the list of six possible explanations for the "anthropic" coincidences in nature which allow intelligent life to evolve...largely inspired and derived from George F.R. Ellis' brilliant brief book, BEFORE THE BEGINNING. He is NOT responsible, though, for the liberties I've taken with his logic or how I've chosen to illustrate it.


You can check out the Many Worlds FAQ by Michael Clive Price, for more detailed information about many-worlds. I mentioned String theory, because its huge number of possible "vacua" is often cited in conjunction with MWI to explain the anthropic coincidences.


Here's "The Multiverse Interpretation of Quantum Mechanics" by Raphael Bousso and Leonard Susskind, for a spirited defense for a multiversal expanation for quantum mechanics.


And here's Martin Gardner's refreshing "Are Universes as Plentiful as Blackberries" throwing cold water (and sanity) on the whole idea.


I know many-worlds refers mainly to tiny events. Still, it has implications for larger events, like the decisions you and I make from day to day, and I couldn't resist borrowing Larry Niven's argument against multiple time-tracks/"worlds" from ALL THE MYRIAD WAYS.


Hawking and Weinberg seem to regard MWI as useful mathematical tools but don't seem as committed to the actuality of alternate existences as say, Sussman or David Deutsch. Many other fine cosmologists and physicists have, to say the least, doubts about the whole enterprise.


Since the whole point of this is to make a reasonable case for theism, some might think it hypocritical to point out that there's no falsifiable evidence for MWI or String theory at the present time, since the same charge can be made about theism.


I'll get to that. We're going to be discussing Occam's Razor a LOT.


I DO think saying MWI is like the Copernican viewpoint---is a bit of a stretch. Yes, it does make things somewhat simpler in the sense as easier to calculate, as orbits are easier to calculate and explain than epicycles. But Copernicus was explaining the motion of stars and planets we could plainly observe, just trying to work out what their motions truly consisted of. MWI proposes trillions of alternate, UNOBSERVED, UNVERIFIABLE "worlds" to explain the one we observe.





Next time: DOES EVERYTHING POSSIBLE EXIST...SOMEWHERE?

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User comments:
tom (Guest)
Al,

Do you think that Newton's derivation of orbital mechanics would be a better analogy to Schrodinger's equation? As you say, epicycles were an attempt to fit things that had already been seen into an understandable framework. But, discover any new thing, and it can only be added to that framework post-hoc.

Newton's equations predict the behavior of all real orbiting bodies that exist, whether they have been observed yet or not. Newton'equations don't create these orbits, but they are all implicit in the equations.

Similarly, Schrodinger's equation doesn't create the Many Worlds universe, they're just a fact of evaluating the equation as it stands. Everett' Many Worlds are already in Schrodinger's equation.

Now, maybe Schrodinger's equation is incomplete, and further steps need to be added, like: "then the wave function collapses". Or maybe the equation is just wrong, even though it predicts the behavior of everything we've seen so far.

Then, Everettian Many Worlds can be immediately falsified by showing that Schrodinger's equation is incomplete or just plain wrong.

Here's something I found last month on Sean Carroll's blog. I think it actually addresses the questions you're asking this week. (Which shows how thorough your research for this has been, because you're asking all of the important questions. Very nice).

http://www.preposterousuniverse.com/blog/2014/06/30/why-the-many-worlds-formulation-of-quantum-mechanics-is-probably-correct/#more-12027

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man in black
man in black
That's a lot to take in
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alschroeder
Yeah, I think a lot of us would like a Quantum-plus theory. You might want to check out this link in turn:



"On the Applicability of Quantum Physics"....



Especially around page three, about the unitary and non-unitary matter of selection of specific worlds. Also check the appendix.


It's a complicated subject. And I'm not ruling out many-worlds altogether. Indeed, a theist is famous--or infamous--for considering other existences, i.e., Heaven or Hell.

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alschroeder
Oops. That should have been a reply to Tom.
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alschroeder
Oh, yeah. It IS.
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tom (Guest)
Al,

Yup, it's the emergent properties that make the world interesting. Nobody would claim to be able to derive European geopolitics, let alone the behavior of a bacterium, from Schrodinger's equation.

Which is why I find the Ellis paper a bit of a muddle.

His stated purpose is to show the limits of applicability of quantum mechanics when applied to macroscopic systems. (Although he doesn't really define where macroscopic starts. Remember, the double-slit demonstration can be done with buckyballs).

He starts by mentionng the common opinion that a suitable application of quantum equations can describe all that happens, and also that there is common talk of the wave function of the universe, and that he will show these opinions are unsupported by evidence.

He begins by describing a problem with making quantum measurements: that there is uncertainty when making a measurement, as opposed to the unique result when solving the equations WHEN THE INITIAL STATE OF THE SYSTEM IS FULLY KNOWN. (Emphasis mine).

This is where the straw man jumps up and starts waving his red flags. Nobody would claim to fully know the initial state of a macroscopic sysrem, let alone the universe.

His conclusion, that the laws of physics put constraints on emergent properties but don't predict their unique behavior, is a reasonable conjecture. I just think his paper doesn't demonstrate clearly how he gets there, if at all.

There are many viable alternatives to Everettian Many Worlds. Unfortunately, I don't see Ellis, in this instance, shedding much light on the question at hand.
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alschroeder
Yeah, you're right. I touched on a lot of the viable alternatives to Everettian Many Worlds last time, like transactional, or pilot wave---all of which go fine with the Schrodinger equations. I will say this--the Everett interpretation makes the fewest assumptions...it just "solves" one problem by invoking a much more complex reality than we can ever... ever... verify.
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jamoecw
thought you were going to go into the steinhardt turok model. well maybe that is slated for a future page. ya the 'infinite' universe theory is problematic on a few basic levels, though it does make good sci fi.
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alschroeder
I thought about going further into String theory, including the Steinhardt Turok model (obviously the illustration with the two branes close together was inspired by that) but I thought digressing too much would take us too far afield. (And make an already long strip twice as long.) Maybe later.
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Frith Ra (Guest)
Just found this today. I will have to follow this more closely, & share it with a few people I know.

Thanks.
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alschroeder
Glad to have you. Hope you enjoy the ride.
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tom (Guest)
Al,

There's going to be a physics workshop later next week, put on by the IBM Research Center, with the topic under discussiin being Quantum Foundations of a Classical Universe.

http://www.jessriedel.com/conf2014/conf2014.html

What caught my attention is that one of the presenters will be Wolciech Zurek, who was cited by George Ellis in his paper On the Applicability of Quantum Physics. Follow the link for Planned Talks for the abstract for Zurek's talk.

Also very cool: at the link for Participent Interests, look at what Ken Olum wants to see discussed.

And the Interests of Hartle, Riedel, Carrolll, and Srednicki. (Wow. Is it Christmas? My birthday?)

(I followed the link for "Anthropic Bias" under Riedel's Interests. Now I have to get THAT book).

I really hope there will be videos from this workship available on the web afterwards. Looks like fun.
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