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At Multiverse Impasse, a New Theory of Scale

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Re: At Multiverse Impasse, a New Theory of Scale

#111

Post by jrussino »

MisterMashable wrote: post #74

There's a very subtle undertone of negativity in this article about physics. Before I get into, William Bardeen is not in the same league as 'Surfer Dude and his E8 Theory of Everything' which throws basic facts about representation theory out the window, coming up with 'todalay boogus' arguments which amazes auntie, mommie and magazine editors but a real physicist would instantly dismiss. Bardeen is the real deal. H…

Are there any particular resources that you recommend for a high-level overview of this kind of stuff? I'm an engineer with a solid grasp of classical mechanics and strong math background, but very little exposure to modern physics (basically, anything discovered after 1905) and I would like to be able to read about and appreciate this type of work. Where to start?

Apologies for taking the conversation off on a tangent, but you seem passionate about this.

Re: At Multiverse Impasse, a New Theory of Scale

#112

Post by sp332 »

mkaziz wrote: post #85
smokel wrote: post #72

Earlier quoted context omitted.

Your statement that we will never get to the bottom may be true, but the reasoning is flawed. Gödel's incompleteness theorems are about mathematical theories, not about physical theories. It may well be that for physical understanding a very limited arithmetic is sufficient. Also, there may be statements that are unprovable, but these might turn out to be irrelevant to sufficiently understanding the universe. Also, a…

Do you not have to start off with a set of axioms though? Assumptions that will never be proven?

The incompleteness theorem describes a tradeoff: A system of axioms cannot be both consistent and complete. But that seems irrelevant, since you could make a system that describes all of physics while not being either consistent or complete. https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_...

Re: At Multiverse Impasse, a New Theory of Scale

#113

Post by xenophonf »

k__ wrote: post #48
snarfy wrote: post #40

Earlier quoted context omitted.

"Any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. In particular, for any consistent, effectively generated formal theory that proves certain basic arithmetic truths, there is an arithmetical statement that is true, but not provable in the theory" - Gödel (Kleene)

Some CS prof. told us this in first semester. After that, Physics was over for me. And I felt that the Planck-scale was somehow a proof for this.

Physics (and science in general) isn't about searching for the Truth. Instead it's about reducing the amount of error in the mental models we use to approximate reality. Like, when a scientist says "the Law of Gravity", they actually mean "our best current guess as to how gravity works, which seems to make accurate predictions in what we consider a statistically significant number of different scenarios, but which is incomplete and perhaps even completely wrong in several other interesting scenarios or edge cases". Only _everything_ in science has a confidence interval, and prefacing every description of some phenomena with the phrase "we're pretty sure this is how this works, but to be perfectly honest, it's only an approximation to some X degrees of accuracy" gets really exhausting, so for stuff we're really, really sure of, like 99.9999% sure, we call it a "Law" (even though it isn't) and move on with our lives.

Re: At Multiverse Impasse, a New Theory of Scale

#115

Post by afafsd »

protonfish wrote: post #60
givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

There is this belief propagated among physicists that smaller scales somehow have more to do with reality. I have never been presented with logic or evidence that convinced me that an electron is somehow more "real" than a molecule or a person or the solar system or the observable universe. I wish the word "reality" would stop being thrown around without justification. "Fundamental" might be a more appropriate term.

>There is this belief propagated among physicists that smaller scales somehow have more to do with reality

Only among high-energy physicists. Perhaps not coincidentally there's also a belief among high-energy physicists that only they count as physicists.

In reality, they're a small minority of physicists. The largest specialty in physics, accounting for about half of all research, is condensed matter physics. Then in no particular order you've got AMO (atomic/molecular/optical), astrophysics, geophysics, biophysics, and a bunch of other stuff sitting between or outside those categories. With the exception of just a few corners of astrophysics, none of these fields needs, or can make sure of, the stuff being done on fundamental interactions; regular old quantum mechanics plus relativity is good enough for describing everything we can actually measure.

Re: At Multiverse Impasse, a New Theory of Scale

#116

Post by kazinator »

xenophonf wrote: post #108
angersock wrote: post #88

Earlier quoted context omitted.

So, erm, what does that buy us? I'm just an engineer, so I'm not sure I see the utility in any of that--sorry to sound closed-minded, but am genuinely curious.

Basic research is the foundation of all engineering. You can't design things without understanding how the universe works. If you need examples, look no further than to particle physics, which has had a huge influence on medical imagery since at least the fluoroscope.

All things hitherto designed have been designed without a complete and truthful understanding of the universe. If we go back in history, we find examples of useful inventions that were produced amid a rather poor understanding. Levers and inclined planes were produced without knowing anything about basic arithmetic, let alone physics.

Re: At Multiverse Impasse, a New Theory of Scale

#117

Post by kazinator »

axilmar wrote: post #45
givan wrote: post #20

I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.

I do not think that it is possible. Any physical system that can be described by a set of mathematical laws is bound to have some axioms that simply cannot be proven within its context. Godel's incompleteness theorems prove that. Hence, we will never get to the bottom of the reality of our universe.

If reality is just math, then it boils down to everything being generated from axioms. Gödel does not tell us that we cannot discover those axioms (and that they are axioms).

Where Gödel comes into the picture is that he gives us no right to believe that only those axioms are all there is.

If the reality is mathematics, Gödel justifies the Multiverse hypothesis: just because we are objects within some theory doesn't mean there don't exist other theories (perhaps superset of this one).

"Unable to prove" in the Gödel sense can be then equated with "unable to peer into another universe".

Gödel's sentence becomes analogous to some phenomenon or artifact of another universe which cannot exist in ours because it cannot be derived from its axioms.

Re: At Multiverse Impasse, a New Theory of Scale

#118

Post by ccvannorman »

I once read that "black holes orbiting each other follow the exact same mathematics as electrons orbiting protons", but I was unable to find the direct source. I did find another article comparing black holes to elementary particles:

http://www.technologyreview.com/view/413483/could-all-partic...

Re: At Multiverse Impasse, a New Theory of Scale

#119

Post by s_baby »

deeviant wrote: post #110
k__ wrote: post #48

Earlier quoted context omitted.

Some CS prof. told us this in first semester. After that, Physics was over for me. And I felt that the Planck-scale was somehow a proof for this.

The thing is, the universe and mathematics are totally separate entities. The universe did not start off "as math", nor is it defined by it. We, as clever little beings found similarities and analogies between the universe and mathematics and leverage those to make conjecture regarding the form and nature of the universe. However, having a "complete" knowledge of either mathematics or the physical universe does not c…

You don't experience the universe directly. You experience it through cognitive constructs and all the limitations that entails.

Re: At Multiverse Impasse, a New Theory of Scale

#120

Post by [deleted] »

differentView wrote: post #97
derefr wrote: post #89

Earlier quoted context omitted.

> The discovery of supersymmetric particles would also be extremely shocking to me, since my institution is heavily involved in CERN LHC experiments, and I haven't heard any hints of a discovery yet. Why does an absence of evidence imply that the arrival of evidence would be shocking? They're doing the experiment because they already believe things are this way and they're trying to get evidence to confirm it. If the…

>They're doing the experiment because they already believe things are this way and they're trying to get evidence to confirm it. Hypothesizing is one thing, but to believe without evidence is just blind faith.

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