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Why not string theory? Because enough is enough

backreaction.blogspot.com

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Re: Why not string theory? Because enough is enough

#111

Post by d0mine »

iofj wrote: post #102
colordrops wrote: post #16

The author says that he "became more convinced [string theorists] are merely building a mathematical toy universe." The explanation for his conclusion was that they kept revising string theory in order to fit observations. I know little of string theory, so I am probably misreading his meaning, but isn't that how all science works? Create a model, then revise it when you get more data.

Think of it this way : "I have solved all of math, physics, and everything else ! Look ! My theory is simply the assembly programming language. Any problem can be expressed in it and anything that we can predict we can predict using some assembly language". You wouldn't consider this to actually predict anything, right ? Despite the statement being perfectly true. Change any prediction into the assembly program print…

It is not obvious that the Universe is computable. https://en.wikipedia.org/wiki/Digital_physics

Re: Why not string theory? Because enough is enough

#112

Post by tim333 »

auntienomen wrote: post #95
tim333 wrote: post #92

Earlier quoted context omitted.

Yup I don't understand it. I'm not convinced others really do either though.

There's a minimum threshold of understanding required to make intelligent commentary on topics like this. Muddled pop-sci and half remembered undergrad material doesn't cut it.

Fair enough but is my description of two slit interference patterns wrong and is there any way you can explain the result with string theory?

Re: Why not string theory? Because enough is enough

#113

Post by auntienomen »

tim333 wrote: post #112
auntienomen wrote: post #95

Earlier quoted context omitted.

There's a minimum threshold of understanding required to make intelligent commentary on topics like this. Muddled pop-sci and half remembered undergrad material doesn't cut it.

Fair enough but is my description of two slit interference patterns wrong and is there any way you can explain the result with string theory?

You can explain it with any quantum mechanical theory. Talking about strings here is a red herring. That's why people are calling you out.

Re: Why not string theory? Because enough is enough

#114

Post by woodandsteel »

jerf wrote: post #96
yoha wrote: post #61

Earlier quoted context omitted.

I mostly agree, but I'd argue that epicycles actually made useful and testable predictions, although we found a simpler description later on. The article underlines a lack of refutable theories. Thus, I think [1] is a better analogy. [1] http://rationalwiki.org/wiki/The_Dragon_in_My_Garage

The characteristic of metaphorical epicycles is that the make simple, testable predictions that are then wrong , which are fixed with another epicycle. Another more subtle aspect of epicycles, real ones this time, is that they are too powerful and can be used to prove anything. You can predict the motion of the planets with epicycles, it's just that the required series is very long or infinite. And with very long ser…

>Another more subtle aspect of epicycles, real ones this time, is that they are too powerful and can be used to prove anything.

String theorists talk about how rich and complex the mathematics is, but maybe that just means it has so many possibilities you can always come up with an explanation to overcome newly-discovered difficulties.

Re: Why not string theory? Because enough is enough

#115

Post by woodandsteel »

The author is taking a different approach called phenomenological quantum gravity that has some promise to be more productive in the long term.

http://backreaction.blogspot.com/2013/06/phenomenological-qu...

From what I understand, she and others are trying to understand what empirical differences a quantum gravity theory of any sort would have, and hopefully will come up with one that can be experimentally observed, which in turn would help people figure out what is the correct quantum gravity theory.

Re: Why not string theory? Because enough is enough

#116

Post by seanmcdirmid »

eli_gottlieb wrote: post #99
seanmcdirmid wrote: post #37

Earlier quoted context omitted.

The idea that the universe runs on a simple program with simple rules hasn't failed us so far. All we have to do is figure out what that simple program is with our capability for abstract symbolic thinking and reasoning; machines are presently very bad at this while humans are less bad at it.

>The idea that the universe runs on a simple program with simple rules hasn't failed us so far. Uhhhh... yes it has. The universe has myriad levels at which a simple program works. If the universe "really" runs on a simple program with simple rules, it's got so large a parameter space that even knowing the program itself is mostly useless to us. https://arxiv.org/abs/1303.6738

A simple program running for billions years on trillions of bits...of course the result isn't going to be "simple." Still, knowing what the code would hardly be useless, and we are spending a lot of resources on trying to figure out.

Re: Why not string theory? Because enough is enough

#117

Post by [deleted] »

dnautics wrote: post #106
ellyagg wrote: post #13

Earlier quoted context omitted.

(Perhaps a bit self-serving for me). So you think she's biased in pointing out that academia has systemic biases?

sorry, that parsed poorly. It's a bit self serving for me . I operate a science nonprofit outside of traditional academia.

[deleted]

Re: Why not string theory? Because enough is enough

#118

Post by j-pb »

espadrine wrote: post #63
j-pb wrote: post #59

Earlier quoted context omitted.

Sure, I choose... "Exhaustive Search in the space of programs". (maybe with some genetic algorithm heuristics to shave of a couple billion years on each query) It's a ML system that can solve any decidable and even some semi decidable problems. Which is (if the church turing thesis holds) everything that can be understood by humans or other. You might not be able to wait around long enough to see it give you a result…

If you allow impractical ML systems, you might as well pick a dice. Sure, the answer is inaccurate, but there's a non-zero probability that it is correct! But, realistically, the ML system you devise cannot learn about features that require knowledge outside of the observable universe.

How does a static dice model computational processes?

What does the universe have to do with the set of computable functions?

Re: Why not string theory? Because enough is enough

#119

Post by jerf »

Gibbon1 wrote: post #108
jerf wrote: post #96

Earlier quoted context omitted.

The characteristic of metaphorical epicycles is that the make simple, testable predictions that are then wrong , which are fixed with another epicycle. Another more subtle aspect of epicycles, real ones this time, is that they are too powerful and can be used to prove anything. You can predict the motion of the planets with epicycles, it's just that the required series is very long or infinite. And with very long ser…

Whack realization of the day for me at least. Epicycles --> Taylor series.

They're more closely related to the Fourier transforms. That's how somebody calculated the actual values that would yield Homer.

Re: Why not string theory? Because enough is enough

#120

Post by ellyagg »

dnautics wrote: post #106
ellyagg wrote: post #13

Earlier quoted context omitted.

(Perhaps a bit self-serving for me). So you think she's biased in pointing out that academia has systemic biases?

sorry, that parsed poorly. It's a bit self serving for me . I operate a science nonprofit outside of traditional academia.

Yeah, I realized later it was possible to interpret that sentence another way. I think my downvoter thought I was making a dumb throwaway snark, but I was actually just confused.
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