Is String Theory Really a Scientific Theory?

vk38 writes, "The New Yorker is running a story on whether String Theory is really a scientific theory or just an abstract exercise in math designed to churn out papers and Ph.Ds for the established academics. The article reviews two current books, by Lee Smolin and Peter Woit, laying out the case against string theory." From the article: "Dozens of string-theory conferences have been held, hundreds of new Ph.D.s have been minted, and thousands of papers have been written. Yet... not a single new testable prediction has been made, not a single theoretical puzzle has been solved. In fact, there is no theory so far — just a set of hunches and calculations suggesting that a theory might exist. And, even if it does, this theory will come in such a bewildering number of versions that it will be of no practical use: a Theory of Nothing... String theory has always had a few vocal skeptics... Sheldon Glashow, who won a Nobel Prize for making one of the last great advances in physics before the beginning of the string-theory era, has likened string theory to a 'new version of medieval theology,' and campaigned to keep string theorists out of his own department at Harvard. (He failed.)"

Comments

Neither Proved Nor Disproved

[eldavojohn]

String theory is a scientific theory that has neither been proved nor disproved to my knowledge.

I could speculate all day on whether or not it is fact but from what I've read, I will make a few statements. It seems that string theory was invented to satisfy some things we could not explain. This doesn't mean it's wrong or right although some people will contend that it is most probably wrong.

As the summary points out, few (if any) of String Theory's propositions can be tested or even observed. So it is simply an unknown right now. We cannot measure the proposed strings so how can we prove if they exist or they don't? We simply can't yet.

A good analogy would be Bohr's early assumptions about the atom. They were wrong but they were a step in the right direction. In hindsight, we see this now but we don't know what the future holds for String Theory. I'm just glad there are people out there thinking outside the box.

Do not fret, however, as scientists have been very resourceful at proving/disproving theories. I submit, for example, the exercise of determining the diameter of the building blocks of matter. Scientists had the idea to fill up one cubic milliletre of oil and dump it on top of a trough of water with a roller across the top. As the oil spread out, they moved the roller further down the trough. Once they started to see non-reflective parts of the water, they moved it back until they agreed the oil was completely spread out to the best of their abilities. Using this area, they determined how thick a molecule of oil could be without precision tools!

Similar ingenious tests have been devised to easily find the diameter of the earth at sunset on a beach with a yard stick or ruler.

So even though we may never be able to measure these strings, there are still some options left to explore to record properties that may prove/disprove their existence. We're merely in the very early stages of the scientific process.

Let us be excited about String Theory, even if it is wrong it sure is interesting. Nothing's wrong with a scientist who dreams, is there?

Re:Neither Proved Nor Disproved

[wirelessbuzzers]

You're right: string theory is not a scientific theory. It's a mathematical theory. That is, it's a collection of mathematical axioms and related proofs (and an extremely unpleasant one, according to a physicist friend of mine).

String theory does provide a model of physics. That is to say, if you set the parameters right, you get something that looks kind of like quantum field theory (which, by the way, is also a mathematical theory in addition to a scientific one). Unfortunately, the math is too hard to deteremine how they differ, and even once a determination is made, string theory has a lot of parameters which will have to be set before real predections are possible. Note that quantum field theories are testable, but only barely. For instance, Howard Georgi's "representations of SU(5)" theory was disproved by experiments in proton decay.

Finally, once string theory does make real predictions, they will be hard to test. In particular, they are likely to require enormous amounts of energy, and accelerator experiments can take years to run and analyze. So it will be a long time yet before string theory becomes scientific.

Smell test fails...

[deepvoid]

String theory fails the smell test, by being so complicated that none of it's predictions can actually be tested. For instance, the theory never explains HOW a dimension can be rolled up in the first place, and wouldn't a rolled up dimension require two more dimensions to adaquately describe. String theory also fails to explain the various constraints described by previous models. Many of the characteristics of string theory are actually inner-wound descriptions of larger characteristics of matter. How would string theory model elastic collisions without claiming the elastic nature of the strings themselves. Alot of physicists' careers have been brought to a standstill for doubting the "faith" of string theory. Scientists should stop the bloodletting and put this smoking pile to rest, along with the other untestable theories that have gone before it.

String theory has nearly stopped all real research into the subatomic universe, in favor of a load of wishfull thinking, written by a few individuals who are too heavily focused on padding their hats to make their heads look bigger.

Let me explain this in programming terms

[Profane MuthaFucka]

The people who make up theories of physics are computer consultants. The people who are raising questions about it are like a cranky customer. The various theories of physics are whatever the consultants make for their customer

The consultants are hired by the customer to write an app. Every time they write the app, the customer comes back and says "that's not quite right". The consultants take off for a few months and come back with a new app that addresses all the objections. Each time the consultants show off their new app, the customer says that the application still isn't quite right.

Finally, after going back and forth for years over this application, the application is getting quite close to what the customer wants but still has a few problems. Eventually, the consultant comes back with an application that is promised to finally, once and for all, solve the customer's problems. The customer takes a look at the application, notices the very thick manual, and realizes that it's going to take YEARS to understand this new application. So, he asks the consultant if this is his idea of a sick joke. No, said the consultant, this application is flexible enough to adapt to any problem you might want to solve or could invent. We call it a "C Compiler".

We seem to have arrived at String Theory just like that.

Re:Compared to Intelligent Design

[Xtifr]

Actually, it's good to point out that "string theory" is a non-scientific theory just like intelligent design. Then they can't use the excuse that we're just persecuting them because we hate religion or something. Science has standards, and neither ST nor ID meet the standards necessary to be called a scientific theory.

Oh, and ID has nothing to do with any religious book. People who argue that know as little about ID as they do about string theory. Although I admit that's beside the point--the creationists who've latched onto the ID label are too stupid to understand the distinction, let alone any of the rest of this discussion. But bottom line, I think that rejecting string theory on the grounds that it's not science is a Good Thing in the war against religious nuts who yammer about "intelligent design" without knowing what it means. It helps eliminate accusations of bias.

Occam's razor

[zoftie]

http://en.wikipedia.org/wiki/Occam's_razor

As far as my popular understanding of the domain goes, it goes like this. Before there was quantum phyiscs. Scientists thought lets smash these atoms see if there is anything inside them. So to the dismay of theirs they have been rewarded with millions of particle types quarks, muons etc etc. that they are trying to categorized catalogue, derive properties of. Some of them didn't like the idea that millions of disjoint test results as material for explaining universe's compositions. With advances in field of mathematics and nod from those early einstein papers they moved on trying produce the theory of everything. Sort of like beautiful theory of relativity. Though relativity has been easy to test and formulas are often recognized by some 6th 7th grade students (E=mc^@), string theory is quite a bit more complicated then that. As it stands of nearly infinite data result domain of quantum physics.

As the string theory suggests that protons neutrons and electrons are singlewaveforms of certain frequency. And smashed atoms and half-waveforms and for some reason decay rapidly.

I suppose it is an excersize in occam's razor placed into the future when theory can be verified.
Why scientists are folling said theory, is in their wet deams they think of Unified field theory, which string theory may well support.

Just like way back as someone mentioned here Bohr's suppositions were incorrect in many ways, but generally incorrect. Perhaps string theory will inspire a new one in the future, that will make more sense.

But for now I would think it should be renamed a hypothesis, away from shameless marketing of non existant product! :)
2c.

works of philosophy vs. works of science

[unani_moose]

As long as there have been "modern scientists", there have been complaints that their theories are untestable and, as such, are works of philosophy and tools of calculation rather than works of science. It's a healthy debate, but critics should have a better background in the philosophy of science. Critics used almost precisely these arguments when the atomic theory was in development. Just because you cannot yet think of a testable hypothesis for a scientific theory does not mean that it does not exist.

As noted at http://web.lemoyne.edu/~giunta/whewell.html, an excerpt of a text by William Whewell from Philosophy of the Inductive Sciences vol. 1, 1840, pp. 406-7 [from Maurice Crosland, ed., The Science of Matter: a Historical Survey (Harmondsworth, UK: Penguin, 1971)]

So far the assumption of such atoms as we have spoken of serves to express those laws of chemical composition which we have referred to, it is a clear and useful generalization. But if the atomic theory be put forwards (and its author, Dr Dalton, appears to have put it forwards with such an intention,) as asserting that chemical elements are really composed of atoms, that is, of such particles not further divisible, we cannot avoid remarking that for such a conclusion, chemical research has not afforded, nor can afford, any satisfactory evidence whatever. The smallest observable quantities of ingredients, as well as the largest, combine according to the laws of proportions and equivalence which have been cited above. How are we to deduce from such facts any inference with regard to the existence of certain smallest possible particles? The theory, when dogmatically taught as a physical truth, asserts that all observable quantities of elements are composed of proportional numbers of particles which can no further be subdivided; but all which observation teaches us is, that if there be such particles, they are smaller than the smallest observable quantities. In chemical experiment, at least, there is not the slightest positive evidence for the existence of such atoms. The assumption of indivisible particles, smaller than the smallest observable, which combine, particle with particle, will explain the phenomena; but the assumption of particles bearing this proportion, but not possessing the property of indivisibility, will explain the phenomena at least equally well. The decision of the question, therefore, whether the atomic hypothesis be the proper way of conceiving the chemical combinations of substances, must depend, not upon chemical facts, but upon our conception of substance.

He then went on to say that it could never be proven and would remain a work of philosophy and a tool for efficient calculation only.

Re:If it's not testable it isn't science.

[alexgieg]

That's just because Philosopher like to think about a lot of things, and some of those seem to be about the concrete world. The moment the guy does this he's switching from Philosophy to Science.

Just because Chemistry is used to develop new gastronomical compounds there's no reason to say that every chemist is a cook, or that Chemistry and Cooking are one and the same thing, or that Cooking is just Chemistry made into practice. Points of contact aren't the same as identity.

Re:If it's not testable it isn't science.

[Chris Pimlott]

I love it how this happens; whenever there is a discussion about whether something is or is not a theory, or isn't actually science, the Science People always piss of the Philosophy Poeple because philosophy always gets used as a dumping ground for everything that starts out with "what if..." but doesn't quality as science. "Damn it guys, we have rules too, you know. Stop sending us your trash!"

It's Not Intelligent Design

[Swift2001]

I'd suppose, if String Theory has no fruitful proofs in the next... while, that it will be abandoned as a scientific theory. Phlogiston, anyone? Theories are like that.

"Intelligent design" will never be abandoned until we're all living in the beginning of A Canticle for Liebowitz, at which point the pointy-headed mutant monks will decide that science and rationality are defeated, and the world is safe again for mad a priori assumptions that the clergy can dispense to peasants.

Re:Not a scientific theory.

[slittle]

Because it attempts to explain our reality - existence as we exist in and perceive it. Deities and the supernatural in general are by definition outside our reality, therefore not science. Even if god(s) exist, that they can mess with our reality is still an abnormality; science deals only with the natural.. uh, nature of our reality. Interference from higher powers may be fact, but it cannot be predicted (or better still, practically exploited), thus irrelevant, scienficially.

Understanding gravity, for example, allows us to navigate probes around our solar system, orbit and/or land them intact on other planets/moons/asteroids. "God did it" may be perfectly true, but it is still not a position of knowledge and understanding, it simply gets us hit in the head with fruit.

Re:Thanks for the troll submission

[k98sven]

I guess the biggest point that I was trying to make is that it's not complete. You can't hold it against the same scrutiny as you would, say, QED, because it's not at the same stage of completeness.

That's what you should have said, then. :)
It's true, you can't judge a theory until it's done. String theory is not done at all.

However, what I think they're saying, what I was saying at least, is that you can judge from the methodology used if it's going to give a useful result or not. As 't Hooft pointed out, at least some string theorists have resorted to problem-solving tactics that will end up creating more problems than they solve.

There's also a general legitimacy problem, not only within string theory (although it's particularily bad there) but within Theoretical Physics as a whole. Some areas of the field are so abstract nowadays, that few know what the heck it's all about. For instance the Bogdanoff affair (http://math.ucr.edu/home/baez/bogdanoff/). Two guys got PhDs on the basis of papers that simply didn't make any sense to anyone. And noone's quite sure whether it was sheer fraud or an honestly intended but ultimately pseudoscientific result.

But the extremely abstract nature of modern theoretical physics makes it very vunerable to this unless they interact with others. And string theory is isolated, even for being theoretical physics.

I think that even if turns out to be the right place to go, it might not be the right way to get there. Intermediate theories such as supersymmetry exist, and are not as isolated from 'real' physics.

Is it even worth attempting then? Emphatically YES!

I agree. I think most critics do as well (although perhaps not the most skeptical ones). It's more or less the only line of attack we've got towards a GUT, and we should persue it.

The real question is: How hard should we persue it? Is it getting more resources than it deserves?
It's the most important field of theory in the sense that it could provide a GUT. But it's the least important one in the sense that a GUT would have little impact on most applied physics.

Personally, I'm waiting for the Holy Grail of molecular physics: A way to solve to the molecular Schrödinger equation that scales linearly. It's been mathematically proven one exists (at least in the density-functional reformulation). We just have no clue what it is. Or even a straightforward way to find out!

Anyway.. Sorry 'bout the "no clue" remark before, that was an uncalled for. I guess I'm just a bit touchy about erroneous statements on my field of expertise.