Why is it called String THEORY?

[dstebbins]

String "theory" has yet to be even so much as tested, much less proven (and yes, I know a theory can never be proven, only disproven; when I say "proven," I mean done at least once with the expected results). At this point, String "theory" is nothing more than a glorified hypothesis, because if you can't verify it in a lab, it's not science. A hypothesis is what you expect to happen, but unlike a theory, it is only backed up with theoretical data and math. Hmmmm, theoretical data and math? Sounds a lot like superstrings, doesn't it?

 

Shouldn't string theory be more appropriately called String Hypothesis?

Edited January 20, 2009 by dstebbins
correct a spelling error.

[D H]

Peter Woit ("Not Even Wrong") and Lee Smolin ("The Trouble with Physics") most likely agree with you. That said, string theory is as much about mathematics as it is about physics. Theory has a rather different meaning in mathematics than in science. Theory in mathematics means "body of knowledge". For example, chaos theory, K-theory, knot theory, measure theory, number theory, ...

[fredrik]

I second those books. I read both Smolins and Woits string critic books. Woit has a stronger emphasis on particle physics, Smolin more on cosmology and conceptual/philosophical issues. If I had to chose on I'd say Smolins, it is deeper. But Woit had a brief history of particle accelerators that Smolin didn't.

 

Most people admit that regardless of wether string theory makes any sense in physics, it has a value in mathematics. But from the point of view of physics that's a lame excuse.

 

I like this Feynmann quote

 

"String theorists don't make predictions, they make excuses."

- R.Feynmann

 

First there is a very very speculative and not very philosophical or intellecutally appealing conjecture, that point particles are strings. The motivation for this idea I've heard takes us back to the pre-QCD days when "there was evidence" of a "string-like" interaction. But that is a very weak motivation IMO. Other than that, the motivation seems to be what comes out of it, ie. spin-2 particles the.

 

But, then after alot of work, it is realized that the speculative conjecture actually are consistent with many possible theories. They have now a set of totally different speculations. So there isn't even a definitie prediction. There is a set of POSSIBLE predictions.

 

To cover that up, an additional conjecture comes up. Instead of rejecting the idea, the idea emerges that there must be a connection with all the possible speculations. A new speculative, not yet captures idea, that "unifies" all the prior initial speculations. (M-theory).

 

The fact that it seems to just get worse and worse, more and more complicated, seems to fit nicely in Feynmanns sentiment.

 

Instead of a silly conjecture to replace points by strings, still withing the old framework, I think we need to review the foundation of concepts at a much deeper level.

 

/Fredrik

[dstebbins]

Peter Woit ("Not Even Wrong") and Lee Smolin ("The Trouble with Physics") most likely agree with you. That said, string theory is as much about mathematics as it is about physics. Theory has a rather different meaning in mathematics than in science. Theory in mathematics means "body of knowledge". For example, chaos theory, K-theory, knot theory, measure theory, number theory, ...

 

But mathematics is the language of science. Also, math is a science in its own right; the science of abstract numbers.

 

Besides, this isn't a question of mathematics; this is a question of physics.

[D H]

This is a question of mathematics as the word "theory" in "string theory" means "mathematical body of knowledge", not "scientific theory".

 

Mathematics is not science. It is a branch of applied logic, which in turn is a branch of philosophy. Many of the thereoms in string theory have been proven -- mathematically, that is. Suppose string theory proves to be an invalid scientific concept. The myriad theorems that came out of string theory will still be true. A mathematical theorem, once proven to be true, remains true forever. Mathematical theorems are not tied to reality. They are tied to logic. Scientific theories can never be proven to be true; they can only be proven to be false.

[ajb]

Mathematics is not science. It is a branch of applied logic, which in turn is a branch of philosophy.

 

That is debatable and I am not sure if all mathematics can be reduced to logic. That is all mathematics can be reduced to a set of relations all derived from each other using logic without making any reference to other mathematical structures and concepts.

 

Any way, as you have said, string theory should be thought of a a mathematical construction that maybe useful in describing physical theories such as quantum gravity and a unified field theory.

 

The ethos should be just as classical mechanics, statistical physics, quantum field theory etc. by themselves are again mathematical theories that are useful in constructing physical theories.

 

For example, unless you specify a Hamiltonian/Lagrangian classical mechanics has little to say about the physical world directly. Or another example is that quantum field theory says nothing much about what will happen at the LHC until you specify a Lagrangian. However, it is very useful to study the mathematical structures behind physics and you can get a deeper understanding of physics that way.

[fredrik]

This might touch also the philosophy and foundation of mathematics and logic itself.

 

If see see mathematics as a language, or system for formulating the laws of physics in a quantitative way, and add to that the historical curiousity that mathematics and physics has developed hand in hand, then from that point of view, I think one can talk about branches of matematics as almost quasi-science in the sense that the "right/good" mathematics should make the laws of physics as simple as possible.

 

Somehow similar to that the "right/good" physical theory should make the best predictions.

 

Given that theories seem to evolve, the efficiency of representation and manipulation of models become important.

 

I think these thinks are why alot of people find their favourite area of mathematics, say various forms of algebra och geometry, and are guided by the vision that when the laws of physics are formualted in this form, it will all become obvious and simple.

 

To a certain extent, that has and is the case. So I for one, think development of mathematics and development of physics somehow correlate. But that's also only half the story. My personal impression is that this is overdone by various people, driver by an almost religious belief in the universality of a certain formalism. I think that's a danger.

 

This view is something both Smoling and Woit also presents in their books.

 

IMHO, I'm along with these, that unless you totally hand in your physics ambitions and are content with the joy pure mathematics (nothing wrong with that per se), the balance in the string minds seems to have totally flipped over on the mathematical religion.

 

Hopefully there is a sensible balance. If one actually tries to quantify the confidence in an idea of a universal formalism, I personally have a hard time to understand how a physicist can be so dedicated in string theory. I see very little appealing fundamental soundness in it's strategy. I find it very speculative from my perspective.

 

/Fredrik

[Jeremymfs]

Directed to fredrik (molecule)

 

Pertaining to your overall views represented above, I would like to comment. Your perspectives appear to communicate an overall sense and acceptance of the potentially ambiguous nature of Reality; possibly allowing for an answer void of meaning or understanding. In this way, you seem deeply rooted in your commitment to yourself to remain objectively grounded in the face of probability being at the root of all existence. From this posture I sense a "freedom from fear" attitude that is probably at the core of your understanding that the universe has and will operate in the absence of "human perception" and ideas. I believe that this freedom from fear is essential if one is to delve into the realm of physics because "Reality's Truth" must be more important to find than to not be proven wrong.

 

Correct me if I am wrong, but you appear to have the general understanding that Reality does not require your cooperation or understanding to exist. This is also why I speculate that you reject Quantum Theory's dependence on the observer. I admire your courage and commitment to this mindset. You are simply trying to narrow the gap between you and your understanding of Reality; knowing the entire time that you will never arrive at your goal. I think this can also be categorized as insanity...but you are proof that it does not have to be painful.

 

Good day,

 

Jeremymfs

[fredrik]

Hello Jeremymfs, welcome to the forum!

 

Directed to fredrik (molecule)

Pertaining to your overall views represented above, I would like to comment. Your perspectives appear to communicate an overall sense and acceptance of the potentially ambiguous nature of Reality; possibly allowing for an answer void of meaning or understanding. In this way, you seem deeply rooted in your commitment to yourself to remain objectively grounded in the face of probability being at the root of all existence. From this posture I sense a "freedom from fear" attitude that is probably at the core of your understanding that the universe has and will operate in the absence of "human perception" and ideas. I believe that this freedom from fear is essential if one is to delve into the realm of physics because "Reality's Truth" must be more important to find than to not be proven wrong.

 

I find your response to be a little unexpected in this context, though interesting. Is that coment based on my posts in this thread, or are you referring to posts in other threads?

 

It seems that your comments, points somewhat away from the topic of the thread?

 

Correct me if I am wrong, but you appear to have the general understanding that Reality does not require your cooperation or understanding to exist. This is also why I speculate that you reject Quantum Theory's dependence on the observer. I admire your courage and commitment to this mindset.

You are simply trying to narrow the gap between you and your understanding of Reality; knowing the entire time that you will never arrive at your goal. I think this can also be categorized as insanity...but you are proof that it does not have to be painful.

 

Since this is your first post, I don't know your style of reasoning, and thus I am unsure wether I understand what your intentions of your words:

 

If you think that I hold the opinon that reality doesn't require my HUMAN understanding to exists, that's for sure. "Observer" doesn't refer to a human. An observer in physics can be an atom, or in principle any system. An "observer, observing/communicating with it's environment" is almost synonymous to a "system interacting with it's environment".

 

So the abstraction I prefer here, doesn't contain ME. However, the home of the abstraction is still MY brain. So I think the answer is both yes and no.

 

But if you think that I suggest that I wan to remove the notion of observer and observations from QT. Ie. there are some people who want to solve the measurement problem by removing the observer. I do not belong to those. You can not talk about "measurements" or "observations" unless there is an observer.

 

In then normal foundations of QM, one talkes about measurements, as if they made objective sense independent of an observer, BEEING ABLE to carry them out. This is my take on the understanding/improvement of QM.

 

But I don't think I mentioend that in this thread? That makes we wonder if you based your post on some other threads?

 

The ambigousness of "reality", lies IMHO at the level of that there is only subective reality, ie. my reality, your reality, an atoms reality etc. Then on top of that we all interact, communicated BASED ON our local perception and understanding of reality. This itself, is what I picture is the origin of physical interactions if communication is analyser and classified.

 

Part of the basic sentiment here, is pretty much THE EARLY parts of Rovelli's reasoning in this Relationa quantum mechanics, but later on I disagree with his choices.

 

Relational Quantum Mechanics

"...Suppose a physical quantity q has value with respect to you, as well as with respect to me. Can we compare these values? Yes we can, by communicating among us. But communication is a physical interaction..."

--

http://arxiv.org/abs/quant-ph/9609002

 

The main point of disagreement is that Rovelli then describes the "communication" with plain QM. While I share his initial spirit, that isn't what I have in mind. But his formulations in the first part of the reasoning is so good it's worth repeating.

 

Edit: Ultimately the critique here, is his unsatisfactory analysis on the physical basis and physical representation (informationwise) about the measure we call probability. Rovelli more or less IMO throws in the towel on that particular point.

 

/Fredrk

[Jeremymfs]

fredrik,

 

This was the only discussion I have read with you in the loop. I was speculating based on what little information you wrote above. I would agree that I got a bit off topic. I will open a new discussion if that is the proper thing to do now. My comments were simply to give credit and appreciation for your mindset. I find it refreshing.

 

Jeremy

[fredrik]

fredrik,

 

This was the only discussion I have read with you in the loop. I was speculating based on what little information you wrote above. I would agree that I got a bit off topic. I will open a new discussion if that is the proper thing to do now. My comments were simply to give credit and appreciation for your mindset. I find it refreshing.

 

Jeremy

 

Thanks.

 

Your response to my response was "unexpected" but that said not less interesting. On the contrary, "the expected" is rarely "interesting".

 

/Fredrik

[Thinker]

But mathematics is the language of science.

 

Mathematics has been the primary tool for scientists to describe the reality in which we live. However, describing something in mathematics does not mean it is true in reality. If we wish to pursue the concept of mathematics' decent from philosophy, then we know that existence is not a predicate and cannot be part of the concept of something. This Law of Philosophy (and by decent, mathematics) holds that just because something exists mathematically (a consept), does not mean that it also exists in reality. Unless we want to debate mathematics' decendance from philosophy and logic.

 

So in the spirit of the origional topic: String theory should be considered a hypotheses (in physics, not neccessarily mathematics), as it has not the scientific exidence to make it a Theory.

 

Though I would like to raise another point: a string theorist once told me that it (string theory) predicts gravity, and that can be used as evidence. any combats to this idea?

[ajb]

 

Though I would like to raise another point: a string theorist once told me that it (string theory) predicts gravity, and that can be used as evidence. any combats to this idea?

 

 

It is about the only existing theory that predicts gravity (the graviton is necessarily part of the spectrum) and it predicts a definite value for the number of dimensions, 10, which is not too bad even if we in fact live in 4.

[Severian]

It is about the only existing theory that predicts gravity (the graviton is necessarily part of the spectrum)

 

You don't need string theory for that. Local supersymmetry (supergravity) will do just fine.

[ajb]

You don't need string theory for that. Local supersymmetry (supergravity) will do just fine.

 

Indeed, in a similar way to gauging the Lorentz group.

 

But the beauty of string theory is that gravitons are including without the need for such gauging. That is, without trying to make a gravity theory you have a gravity theory.

[Severian]

The motivation for gauging supersymmetry is not gravity. The motivation is that most of the other symmetries are gauged, so why not try this one too. Gravity and the graviton just falls out.

[ajb]

The motivation for gauging supersymmetry is not gravity. The motivation is that most of the other symmetries are gauged, so why not try this one too. Gravity and the graviton just falls out.

 

But surely as the super Poincare group contains the Poincare group then is it not expected that (some kind of) gravity would fall out?