String theory in one sentence please

[MTd2]

If I switch almost all periods for commas, except for the last one, in both Polchinski's books and copy and paste them together, does it count as 1 sentence?

 

[suprised]

That is true, but no one can understand Quantum Mechanics yet they accept it, it comes down to falsifiability most likely.

Kevin,

Well, I know many people who don't accept quantum mechanics, but also don't have the faintest clue about it: "I don't understand it, so it must be wrong". Same applies here, read some of the comments above and see what I mean...

 

[inflector]

Yes, let's discuss this precise statement (and nothing else).
Can you prove that string theory (the *theory*, not our actual knowledge of some solutions) is not provably wrong? The answer is a simple Yes or No. If the answer is no, then the statement was false. If the answer is yes, then the statement is true. That's all that I am saying.

..[snip]...

No but it does not prove that the theory is not provably wrong. Only that we haven't found a way yet to falsify it. That's a completely different statement. That's all I am saying.

Well, the same could be said about the existence of God right? Can you prove that the theory of God is not provably wrong? For any test you might think to invoke, some theist somewhere will always be able to come up with a new place for God to hide.

Not currently provably wrong means that String theory is not currently a theory. At best, it's the beginning of an idea that might one day be a theory. Sure, we can't prove that it won't one day be a theory. I'll grant you that point. But again, you can say the same thing about God. Can you prove that we won't one day have a theory of God that is scientifically valid?

 

[suprised]

Of course string theory can be proven to be wrong. The very nature of stringyness is string resonances, an infinite tower of excitations. If one cannot find them, then string theory is disproven.

This is a matter of principle, whether one could actually do such experiments is a different question. But if people come up with this falsification idea, which is a matter of philosopy, then that's the answer at the same level of philosophy.

If people were smart enough to do a little bit of reading, and I mean serious reading, then this discussion woulnd't come up every couple of weeks.

 

[CHIKO-2010]

String theory is the only known consistent quantum-mechanical completion of gravity which also, at least in principle, is capable to describe known particle physics at ultra-high energies.

 

[suprised]

Well, the same could be said about the existence of God right? ..
..
Not currently provably wrong means that String theory is not currently a theory.

Sorry this is BS. It is not just a matter of randomly "declaring" God or String Theory or other ideas to underly things. Science works a bit different! What goes in string theory is an enormous amount of hard, highly non-trivial computational _results_. And these tell which things work or can work, and which not. This gives strong scientific reasons for it, unlike for God. At least I don't know of any computation that could be interpreted either in favor of or against the existence of a god.

 

[inflector]

Sorry this is BS.

Actually, it's a particular dialectic technique called reductio ad absurdum.

It is not just a matter of randomly "declaring" God or String Theory or other ideas to underly things. Science works a bit different! What goes in string theory is an enormous amount of hard, highly non-trivial computational _results_. And these tell which things work or can work, and which not. This gives strong scientific reasons for it, unlike for God. At least I don't know of any computation that could be interpreted either in favor of or against the existence of a god.

I was NOT proposing that belief in God is as scientific as belief in String Theory. What I was showing is that the specific test of whether or not a specific theory or idea is: "not provably wrong," is not useful as a discriminant because many other ideas which are not scientific or even useful share the trait of being "not provably wrong."

Therefore, I suggest that the proponents of String Theory not use this particular test as part of their argument. Its very use is the opposite of persuasive and smacks of desperation.

 

[Haelfix]

I would suggest staying away from this board then, b/c almost by definition, everything 'beyond the standard model' is not falsiable in *practise*. Quantum gravity (not just string theory) has always suffers from that fate.

Now, again if we had some sort of probe into the early universe or a galaxy wide particle accelerator, then sure we would look for stringy signatures and they would be highly apparent and the theory could be falsified rapidly. But we don't, and probably never will so pure theory work and plausibility arguments is the best you can do (without getting lucky)

 

[Kevin_Axion]

Perhaps the easiest approach would be to look for other intelligent beings and see what they have discovered.

 

[inflector]

I would suggest staying away from this board then, b/c almost by definition, everything 'beyond the standard model' is not falsiable in *practise*. Quantum gravity (not just string theory) has always suffers from that fate.

I am not proposing and have not proposed that we shouldn't consider and work on ideas which are not currently falsifiable. I am merely saying that this lack of provable falsifiability is not a point in their favor.

And I should further add that scientists, especially those who write popular books on physics, should STOP talking about these ideas as if they have been proven until they actually have some experimental verification.

Because, in the end, not provably falsifiable is exactly equivalent to not provably not even wrong which is also equivalent to not provably not not even wrong.

 

[MTd2]

I would suggest staying away from this board then, b/c almost by definition, everything 'beyond the standard model' is not falsiable in *practise*. Quantum gravity (not just string theory) has always suffers from that fate.

Not really... Not everything "beyond standard model" is quantum gravity. It's just that this board has its standards twisted.

 

[Kevin_Axion]

Michio Kaku always alludes to the idea of a single equation that would describe all physical processes in our universe which derives from Superstring Theory/String Field Theory (can someone explain the difference?). What form would this equations be in, a Lagrangian Density?

 

[atyy]

Michio Kaku always alludes to the idea of a single equation that would describe all physical processes in our universe which derives from Superstring Theory/String Field Theory (can someone explain the difference?). What form would this equations be in, a Lagrangian Density?

A complete formulation of string theory is unknown http://www.blau.itp.unibe.ch/stqg.pdf

 

[Kevin_Axion]

I know, I'm just asking if one were to be found what form would it be in? For instance the Standard Model can be formulated in a Lagrangian density.

 

[atyy]

I know, I'm just asking if one were to be found what form would it be in? For instance the Standard Model can be formulated in a Lagrangian density.

In AdS/CFT, the CFT is a standard field theory formulated with a Lagrangian.

However, AdS/CFT is probably not all of string theory, and suprised has mentioned something about derived, Fukaya categories in the past.

 

[tom.stoer]

I collected the statements we had over the last year; hopefully the quotes are complete and correct.

String theory tries to construct a supersymmetric framework in 10 (11) dimensions from which all known elementary particles and interactions including gravity emerge (uniquely) from the modes of an one-dimensional, vibrating string.

According to string theory, elementary particles are not really pointlike, but have a shape of a short string, too short to be visible with present technology.

String is a purely mathematical attempt to model reality. It is not provably wrong [and may never be], but, empirically unsatisfying thus far. It explains some observations, mostly at the quantum level, but otherwise has no compelling observational support.

String is a purely mathematical attempt to model reality. It is not provably wrong [and may never be], but, empirically unsatisfying thus far. It has no observational support.

String theory is a physical model based on tiny strings that incorporates both quantum mechanics and general relativity and attempts to unify gravity with particle physics.

String theory is an attempt to mathematically unify quantum mechanics and general relativity by using strings vibrating in multiple spatial dimensions as the fundamental building blocks of the universe.

String theory is the only known consistent quantum-mechanical completion of gravity which also, at least in principle, is capable to describe known particle physics at ultra-high energies.

 

[Entropee]

Thank you Tom, man its been a while since I wrote this essay though haha. Still seems to be a popular thread though.

 

[QGravity]

String Theory is an Idea that on mathematical side was & is on of the most fruitful Ideas that come to human mind (Just consider Geometric mirror symmetry, Seiberg-Witten theory (in comparison of donaldson theory for computing topological invariants , classification and other aspects of low-dimensional topology), string homology and ...) But on physical side (until now!) is not very desirable.
If LHC can see Ideas like extra dimension & supersymmetry, we can still believe in String Theory.