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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

#101

Post by dfox »

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?

From the mathematical point of view, physics is about finding smallest set of axioms from which you can mathematically derive complete theory of universe's behavior. Validity of such axioms is in turn validated by experiments (by testing whether results match theory derived from given axioms)

Re: At Multiverse Impasse, a New Theory of Scale

#102

Post by dllthomas »

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…

"'todalay boogus' arguments which amazes auntie, mommie and magazine editors but a real physicist would instantly dismiss."

For the record, my father was far more amazed by rambling, not entirely coherent speculative physics ideas than my mother or either of my aunts.

Re: At Multiverse Impasse, a New Theory of Scale

#103

Post by dllthomas »

pfortuny wrote: post #65
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)

It is funny because if nature is discrete then Gödel has nothing to say about it. Only our present MODELS fail to deal with finiteness properly.

Weren't the original formulation of Gödel's theorems dealing with natural numbers (a discrete setting)?

Re: At Multiverse Impasse, a New Theory of Scale

#104

Post by dllthomas »

dfox wrote: post #101
mkaziz wrote: post #85

Earlier quoted context omitted.

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

From the mathematical point of view, physics is about finding smallest set of axioms from which you can mathematically derive complete theory of universe's behavior. Validity of such axioms is in turn validated by experiments (by testing whether results match theory derived from given axioms)

It is true that they will never be "proven", but that doesn't mean we can't build a tremendous confidence in them through experimentation. (Which is to say "I agree", but I wanted to put a slightly different spin on it.)

Re: At Multiverse Impasse, a New Theory of Scale

#105

Post by 21echoes »

angersock wrote: post #88
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…

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.

The road from theoretical physics to engineering is a very long one, so it's very hard to predict exactly what this would buy us. Relativity, for instance, spent a long time with no concrete engineering benefit, but now it allows GPS to be much more accurate by adjusting for the time dilation on GPS satellite clocks. As we get closer and closer to the mysteries at the heart of the universe, I think it's safe to say that the engineering benefit will be both more arcane and more powerful.

Re: At Multiverse Impasse, a New Theory of Scale

#106

Post by nilaykumar »

evanb wrote: post #83
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…

Do you have any rumors or specific knowledge (even if it's not something you'll share) regarding SUSY? They found missing energy? A new plethora of resonances? Higgsinos or sfermions? Something more exotic?

By the end of the last run, the people I talked to at CERN were fairly certain that there's no SUSY in the current dataset and that SUSY will likely not be found during the upcoming run. But perhaps the people I talked to are simply of a different persuasion.

Re: At Multiverse Impasse, a New Theory of Scale

#107

Post by pfortuny »

dllthomas wrote: post #103
pfortuny wrote: post #65

Earlier quoted context omitted.

It is funny because if nature is discrete then Gödel has nothing to say about it. Only our present MODELS fail to deal with finiteness properly.

Weren't the original formulation of Gödel's theorems dealing with natural numbers (a discrete setting)?

Sorry I mistook the term: finite, not discrete.

Re: At Multiverse Impasse, a New Theory of Scale

#108

Post by xenophonf »

angersock wrote: post #88
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…

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.

Re: At Multiverse Impasse, a New Theory of Scale

#109

Post by andrewflnr »

hcarvalhoalves wrote: post #96

> Perhaps the fundamental description of the universe does not include the concepts of “mass” and “length,” implying that at its core, nature lacks a sense of scale. This little-explored idea, known as scale symmetry, (...) Isn't the word for that fractal ?

Ah, no, that's a completely different sense of scale invariance. In a fractal you still have to measure the sizes of different similar structures, and generally pay attention to length. It seems that this article is discussing a much deeper abandonment of length.

Re: At Multiverse Impasse, a New Theory of Scale

#110

Post by deeviant »

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.

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 confer complete knowledge of the other.

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