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Why not string theory? Because enough is enough

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81–90 of 123 posts

Re: Why not string theory? Because enough is enough

#81

Earlier quoted context omitted.

It's called adding epicycles : http://rationalwiki.org/wiki/Adding_epicycles

What's wrong with that? Epicycles are a good testable model. They were discarded when a better one was developed.

Well that's really all that is wrong with it: you are adding epicycles instead of working on a better theory. In analogy: once a language is turing complete you can do anything in it, so you can keep using brainfuck to make a gui, but probably it would be easier in java...

Re: Why not string theory? Because enough is enough

#82
post #52
post #21

Earlier quoted context omitted.

So you feel strong theory connects to reality, and is falsifiable and avoids "piling on epicycles"? Will string theory be more parsimonious than the the more concrete model of physics it tries to model?

Of course string theory is falsifiable. String theory reduces to quantum field theory in some limit and to general relativity in some other limit. Unlike all the other previous theories, string theory is the theory that has resisted all efforts to falsify it yet. It's a ridiculous misconception floating around that string theory can't make predictions, when in fact string theory is the only theory we have so far that…

> tring theory is the only theory we have so far that predicts all known observed phenomena.

That would have been impressive if it didn't also predicts even more that is neither known or observed.

Re: Why not string theory? Because enough is enough

#83
post #66
post #14

Earlier quoted context omitted.

It's a fundamental mistake to assume that these are "real" strings being talked about. String theory is about the idea that reality is best modeled as, notionally, strings - i.e. the mathematics looks a bit like them if you sort of squint and look at it really hard. But there's a really good reason strings are a compelling here: because near as we can tell, vibrational frequency is really important to particle physic…

>really good reason strings are a compelling here: because near as we can tell, vibrational frequency is really important to particle physics I can give a sort of counter argument. Fair enough the relationship between frequency and energy and also wavelength and momentum are fundamental to physics. But consider maybe the classic experiment where you demonstrate that, where you have a barrier with two slits and fire p…

>I can give a sort of counter argument.

You can't because you clearly have an incredibly shallow understanding of string theory (I do too). For one thing, you're completely stuck on the metaphor of the 'string' and you're trying to apply it to a very shallow understanding of Quantum Mechanics and complaining that it doesn't make sense. Okay.

I think it's cool to talk about fundamental research but taking it one step further and saying that some theory X isn't correct because it doesn't make sense to ME, a non-professional physicist, is a step too far. Be more humble.

Re: Why not string theory? Because enough is enough

#84
post #3

I've got a theory that string theory is more of a sociological phenomena than real science. It started as a genuine attempt to model how the nucleus was held together and then continued because it's a good area to do maths and write papers rather than because it models reality. One thing I don't get, which may be down to my own stupidity - take maybe the simplest interaction in physics - you have two electrons in spa…

>I've got a theory that string theory is more of a sociological phenomena than real science. Yes. I have a friend with a PhD in physics, and he says that a generation of string theory people basically just shouted everyone else down in a rather obnoxious way. Other critics (e.g. Lee Smolin) have said similar things, albeit slightly more politely. At some point it stopped being science and became more about careers, r…

It reminds me a little of the phenomena of efficient market theory in economics / finance. Academics were drawn to it partly because it enables them to do a lot of fancy mathematics whereas if you look at inefficiencies like the stuff that went on in the movie The Big Short then the academics don't really have much of an edge against people working in the field. So much academic stuff goes 'assuming efficient markets', blah blah... which is not actually wrong but maybe a misallocation of resources from looking at bubbles and crashes which could have helped avoid the whole 2006 episode.

I agree the blog seems very good.

Re: Why not string theory? Because enough is enough

#85

Earlier quoted context omitted.

It's called adding epicycles : http://rationalwiki.org/wiki/Adding_epicycles

What's wrong with that? Epicycles are a good testable model. They were discarded when a better one was developed.

What's wrong is that you're trying to make a round peg fit a square role.

The problem was not that it was discarded, but what happened between new data and getting discarded and how long it took.

You don't want Epicycles because theories should be "simple" and Epicycles are added exceptions

Re: Why not string theory? Because enough is enough

#86
post #41

Earlier quoted context omitted.

And that, to put it succinctly, is the problem. In the pursuit of a Theory of Everything, you wind up with a Theory of Anything. If there's no particular reason why things are the way they are in this universe, then you're reduced to the simpler observationally-verifiable model anyway since the elegant overarching framework is essentially useless. It becomes a philosophy of the ought rather than a description of the…

Say, you shuffle a deck of cards, and shuffle really well. Now you could spend forever by drawing cards from the deck and analyzing the sequence and trying to think of theories how to predict the next card. But the is no ultimate reason behind why the deck was shuffled into this order and not some other. Perhaps the shape of natural laws (the four fundamental interactions) and the values of natural constants have bee…

The deck of cards analogy is sort of getting to the anthropic principle -- the natural laws could have come out any number of ways, but most of the other shuffles wouldn't result in us being here to contemplate them.

Re: Why not string theory? Because enough is enough

#87

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.

Science also prescribes that you use the smallest (simplest) model that fits the data. String theory arguably does not adhere to that.

Re: Why not string theory? Because enough is enough

#88
post #3

I've got a theory that string theory is more of a sociological phenomena than real science. It started as a genuine attempt to model how the nucleus was held together and then continued because it's a good area to do maths and write papers rather than because it models reality. One thing I don't get, which may be down to my own stupidity - take maybe the simplest interaction in physics - you have two electrons in spa…

>I've got a theory that string theory is more of a sociological phenomena than real science. Yes. I have a friend with a PhD in physics, and he says that a generation of string theory people basically just shouted everyone else down in a rather obnoxious way. Other critics (e.g. Lee Smolin) have said similar things, albeit slightly more politely. At some point it stopped being science and became more about careers, r…

Abstruse Goose also has some deep wisdom about string theory. I particularly like this one:

http://abstrusegoose.com/424

Re: Why not string theory? Because enough is enough

#89
post #62
post #11

Earlier quoted context omitted.

I've got a theory that string theory is more of a sociological phenomena than real science. I've got to say, that comes across as awfully dismissive toward a whole lot of very thoughtful people. I'm not entirely sure what you mean by it. Certainly all of the string theorists I've known (it's my profession) have talked as if they believed their work was involved in a "genuine attempt" to model reality. Maybe a physici…

>most of the questions you've asked are really quantum field theory questions: the string theory connection is almost entirely unimportant in that regime My issue with the two electrons repelling scenario is that in normal quantum field theory it's modeled, I think, as the exchange of virtual photons and given that we don't really understand what a photon is and that they have odd spread out kind of properties that s…

I'll be honest: high energy physics isn't really an area where "hunches" carry a lot of weight, at least if those hunches aren't grounded in a pretty thorough understanding of particle physics and general relativity.

The language of "pinching off into new strings" is of course largely an analogy, one which captures some of the mathematical features of string interactions reasonably well while probably obscuring others. What's really going on underneath that analogy is just as "abstractly mathematical" as you could ask for: a (boundary?) conformal field theory defined on the 1+1-dimensional string world sheet, which allows just a single unique self-consistent mode of interaction. It is complicated, but honestly, so is standard quantum field theory when you really dig into it, and if you're familiar with the underlying math and physics this description is surprisingly elegant.

Re: Why not string theory? Because enough is enough

#90
post #13

"[A]cademia is currently organized so that it invites communal reinforcement, prevents researchers from leaving fields whose promise is dwindling, and supports a rich-get-richer trend." A really awesome quote there. (Perhaps a bit self-serving for me).

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

SKDH is as much of a physics insider as they come. So, if anything, she has something to lose.
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