New Calculations May Lead To a Test For String Theory

dexmachina writes "A team of theoreticians, led by a group from Imperial College London, has released calculations that show string theory makes specific, testable predictions about the behaviour of quantum entangled particles. Professor Mike Duff, lead author of the study from the Department of Theoretical Physics at Imperial College London, commented, 'This will not be proof that string theory is the right "theory of everything" that is being sought by cosmologists and particle physicists. However, it will be very important to theoreticians because it will demonstrate whether or not string theory works, even if its application is in an unexpected and unrelated area of physics.' In other words, string theory may finally have shed its critics' most common complaint: unfalsifiability. However, given the second most common complaint, I can't help but wonder: which string theory?" Update: 09/03 23:34 GMT by S : Columbia University's Peter Woit, author of the Not Even Wrong blog, says these claims are overblown, and adds that a number of string theorists said as much to Wired.

Comments

Well...

[Korbinus]

That's a good news for Dr. Leonard Leakey Hofstadter...

Re:Well...

[Jason Kimball]

He may finally get his bazinga!

Re:Well...

[mcgrew]

"With all due respect, Dr. Hofstadter... are you on crack?" -- Dr. George F. Smoot III
(link)

Re:Well...

[Anonymous Coward]

That's a good news for Dr. Leonard Leakey Hofstadter...

that was my first thought too

Re:Well...

[treeves]

The love-child of Louise Leakey and Douglas Hofstadter?
Or maybe of Mary Leakey and Robert Hofstadter?

Re:Well...

[Anonymous Coward]

Sheldon is the string theorist.

Oops

[dexmachina]

It seems I may have jumped the gun on this one. My bad for being such an easy mark of sensationalist pop science headlines.

Re:Oops

[Anonymous Coward]

We can all see that popular science journalism with their associated actors in PR isn't that far from tabloid-quality Pavlovian-level attention capturing industry. But, can anyone explain how University PR works? How does it connect to funding and reputation, and why does a university of all places put out misleading stories at all?

Re:Oops

[Anonymous Coward]

I first read that as:

It seems I may have jumped the gun [columbine.edu] on this one.

Re:Oops

[maxwell demon]

Indeed, it's worse. While I don't know much about string theory, I do work in the field of entanglement. And there's no way you could experimentally test this classification, for the simple reason that it's a classification. It may be a more or less useful classification, but you cannot experimentally test whether a classification is right (apart from that an reasonable entanglement classification has to be SLOCC invariant, which this classification is, but of course the others are as well). Trying to experimentally test if a classification is right is like doing an experiment on whether classifying a fruit on its color or on its size is more correct. What you can do is to evaluate the usefulness of a classification (i.e. does it tell you something interesting about the state, like what you can do with it; in the fruit example, you might find that classifying fruits on nutrition value may generally be more useful than classifying on water content).

Re:Oops

[oldhack]

Are you Peter Woit?

Re:Oops

[bayduv1n]

Hi. I have a very stupid question for someone working in the field of entanglement.

Spin is measured as up or down, but presumably the spin is actually at some angle in between. So the up or down measurement is rounding the actually spin. Is the resulting rounding error of any significance? Is the accumulation of rounding errors on multiple measurements of any significance? Or, as is most likely, is this a nonsensical question?

Thanks

Re:Oops

[maxwell demon]

Hi. I have a very stupid question for someone working in the field of entanglement.

Spin is measured as up or down, but presumably the spin is actually at some angle in between. So the up or down measurement is rounding the actually spin. Is the resulting rounding error of any significance? Is the accumulation of rounding errors on multiple measurements of any significance? Or, as is most likely, is this a nonsensical question?

Thanks

The measurement is not rounding the real spin value. After the measurement, the spin is up or down (in the measurement direction), not any angle in between (assuming an ideal measurement, of course). And the direction of the spin before measurement decides the probability of getting up or down (that is, even if your spin is almost up you still have a (low) probability to get "down" (rounding "almost up" would instead always give "up"). Since there's no rounding, there are no rounding errors either (there are, of course, errors due to your necessarily non-perfect measurement equipment, just like in classical physics; unlike in classical physics, this can result in you getting sometimes the opposite result, but only with low probability).

Re:Oops

[Pauli]

I am not working in the field of entanglement, but I am an NMR spectroscopist, so I work with spins. The spin *is* really only up or down (or a combination of the two), but not ever some "angle" in between. Probably the most correct definition of electron spin is Wolfgang Pauli's original statement: "Classically non-describable two-valuedness." Trying to rationalize it as something spinning is incorrect and will generally lead you to false conclusions. In NMR spectroscopy, different nuclei couple to each other and the different spin states produce separate distinct peaks for each value of their neighbor's spin states. Collections of multiple nuclei produce binomial patterns, but each nucleus is always in some particular state or perhaps a superposition of different states, which is not the same as "being in between" different states.

Re:Oops

[iris-n]

I don't think I can blame your for not reading the paper. They just lied and lied and lied in the press release: "Researchers describe how to carry out the first experimental test of string theory"

Come on! I know that press releases are about PR not science but they should at least bear any relation to the paper.

Look in the paper. The word experiment only appears once, and they don't claim to describe an experiment; not even that it is possible or conclusive.

That said, the question is: who is the lier? The scientists or the marketers? If I can take as true the quotes at TFA, Mike Duff.

Well, at least you showed us whose research we should ignore.

Re:Oops

[Anonymous Coward]

Nothing is actually 'spinning'. They could call it color and use black and white.

Re:Oops

[sco08y]

It seems I may have jumped the gun on this one. My bad for being such an easy mark of sensationalist pop science headlines.

If we took time to accept your apology, that would divert precious comments from the long /. tradition of calling for the ritual disembowelment of the editors.

Re:Oops

[SETIGuy]

At this University at least, PR for specific projects is driven by the PIs themselves. Anything in a University press release has been provided by the PI and drafts of the press release have been fact checked by the PI. In other words, if there's a problem or a exaggerated claim, blame the scientist.

Re:Oops

[SETIGuy]

And no, there is no peer review of a press release unless the PI arranges it himself.

Re:Oops

[Anonymous Coward]

Hi. I have a very stupid question for someone working in the field of entanglement.

WTF is a SLOCC invariant? Don't bother if its too much trouble, which it probably is.

Re:Oops

[maxwell demon]

However for spin 1/2 (i.e. the case where you get "up" and "down"), you actually can map the states to directions, and that direction is the direction where you get "up" with 100% probability (modulo measurement errors, of course). Moreover, the spin is really an angular momentum (although you're right that there's nothing actually spinning), therefore "spin" is clearly a better name than "color" (not to mention that "color" is already taken for QCD :-))

Re:Oops

[maxwell demon]

"LOCC" stands for "local operations and classical communication", that is, locally you may do whatever you want with your part of the quantum system, but communication has to be classical (i.e. phone calls are allowed, sending quantum systems isn't). The "S" in "SLOCC" stands for "stochastic": it means to allow also operations which succeed only sometimes (this allows e.g. to increase - but not create - entanglement; on average entanglement will never increase, however). Now states are called "SLOCC equivalent" if you can reach each one from the other by SLOCC (for example, an entangled state is not SLOCC equivalent to an unentangled state, because while you can easily go from the entangled to the unentangled state, you cannot get back). That means, they obviously have the same sort of entanglement. Therefore an entanglement classification should put all SLOCC equivalent states into the same class, i.e. reversible SLOCC should not change the class. In other words, the classification should be invariant under (reversible) SLOCC. So in short, "SLOCC invariant" means that if you can get, with some non-vanishing probability, from one state to the other and back using only local operations and classical communication, then your states belong in the same class.

Now an obvious idea would be to use just this as criterion, i.e. two states are in the same class iff they are SLOCC equivalent (i.e. your classes are just the SLOCC equivalence classes). This works fine for up to three qubits (two-level systems), but with four or more qubits you get infinitely many classes this way (indeed, even uncountably many), therefore to be useful, a further classification is needed, preferrably with a finite number of classes (or "families", to distinguish them from the SLOCC equivalence classes). And that's basically what the authors of the article in question provided: A classification with a final number of families. What's special at their classification is that they used some equivalence between the math of qubit entanglement problems and certain string theory problems to arrive at it.

Re:Oops

[david_thornley]

Your first problem is the "presumably". Our common sense and understanding derive from experience with physics at a certain scale, and doesn't necessarily apply when you scale up or down enough. If you think of photons or electrons as little spinning balls, you're likely to get things wrong. What I am going to explain is based on how things actually behave at the quantum level.

There is no rounding error on a spin measurement. Whatever you get is what the particle is. There is no accumulation of rounding errors, because there are no rounding errors.

You can speak of what the spin was only in terms of the probability of getting an up or down (or something that translates into that). However, you don't get the opportunity to do more than one measurement on one particle. If you've measured up, it will continue to measure up. That means that probability can't really be measured. You can get a stream of electrons of a particular spin, and you can know they're all the same spin, and you can count how many are up and how many are down and do it at different angles and conclude in detail what the spin was. That's one big way quantum mechanics merges into classical mechanics: statistically. We can't perceive a single particle ourselves (it's possible to see a burst of 100 photons, but that's about it), so the statistical properties are as real as the individual properties.

It may be tempting to think of a measurement as something that imposes a spin, but that doesn't work either, because it is possible to unmeasure things. You measure electron spins by separating a stream into an up stream and a down stream, but you can unmeasure by mixing them back together. If there's no way you can possibly tell what the results of a measurement were, you haven't measured something. (This means no possible way; if there's a way you just haven't used, then the particles still count as measured.) If an electron did have a spin at a given angle, like a little ball, then either a measurement would leave that spin intact, which it doesn't do, or it would change the spin, meaning the spin couldn't be unmeasured.

People keep proposing little classical models, typically called "hidden variable theories", in which there would be some classically understandable thing about single particles that would account for the weird measurements, and people keep testing for them and finding them wrong. You can't understand quantum mechanics in terms of classical physics.

And when it fails this test too

[OeLeWaPpErKe]

People will change their mind about it ? Oh right ... string theory already failed every test that was ever thrown at it ... and they didn't drop it (probably for lack of an alternative, and prior investment, but still ... scientists are supposed to be above that sort of thing).

The one real test String theory was subjected to was the long-term evolution of the universe. All (10^55) possible string theores seemed to predict a slowing expansion of the universe. Then it was measured, and as we all know we observed an accelerated expansion of the universe. Whoops.

So with a lot of "probably" correct hocus pocus (and we're talking some serious trickery here) a few (billion) string theories were shown to allow for (mostly temporary) accelerated expansion ... with a *lot* of side conditions. And all sorts of unobservable conditions, like other branes taking up specific positions compared to our own ... etc. As I said, lots of magic values needed to make these things work.

Believing in String theory is a bit like searching for the Aether in 1900, or assuming the correctness of math before Godel (who proved math is not consistent, whoops)

Re:And when it fails this test too

[zero.kalvin]

All 10^55? Who had the time to calculate them all ? Calculation of one configuration already takes a lot of time!! So please Citation!

Re:And when it fails this test too

[Anonymous Coward]

Hey if it doesn't work out then they will invent dark strings? Seriously though when is someone going to answer the BIG question... can you really make something out of nothing?

Re:And when it fails this test too

[Anonymous Coward]

Believing in String theory is a bit like searching for the Aether in 1900, or assuming the correctness of math before Godel (who proved math is not consistent, whoops)

or like believing in god. God has also failed every test thrown at it.

Re:And when it fails this test too

[IRWolfie-]

Yikes, I see you've never heard of exaggeration for effect. There are many different forms of the the hypothesis, and alternative hypotheses, check google.

Re:And when it fails this test too

[guyminuslife]

God is love. You believe in love, don't you? So there must be God, because there is love.

Obviously, it follows that love created the world in six days. Then love created a flood that destroyed just about fucking everyone, because you don't fuck with love, love is a sociopath.

Re:And when it fails this test too

[Anonymous Coward]

Just for the record: Gödel did not proof math to be not consistent. He showed two things:

1. That in every axiomatic system strong enough to capture aithmetic there necessarily are true sentences that can be expressed with the means of the system but cannot be deduced from the axioms (he presented a method to construct such sentences).

2. You cannot deduce a system's consistency from the axioms of such a system. (Which is something completely different from prooving that math is not consistent).

Re:And when it fails this test too

[jamesh]

God has also failed every test thrown at it.

I don't believe in God, but if he (i'll use the 'he' pronoun for convenience) exists then he's the one making up the rules not us, so 'testing' for God is a bit dumb. We can prove that the universe could have happened without God but we can't prove he doesn't exist.

And if he does exist I bet string theory is giving him the best laugh he's had in centuries :)

Re:And when it fails this test too

[Walt Dismal]

Well hell, I still haven't given up believing in the aether. or that ghosts can pass through solid objects, except for the floor. A man's not a man without something to believe in, I say. Nixon for President in '012. And I have a proof a bit too large to scribble in the margin here about P and NP.

Re:And when it fails this test too

[Krahar]

[...] or assuming the correctness of math before Godel (who proved math is not consistent, whoops)

You got to improve your trolling - you have to be irrational and coarse enough to be enraging, yet not so loony that you self-identify as a troll. I rate you a 6 out of 10 for aggravating, which is OK I guess. What puts you over the top is stating that Godel proved that math is inconsistent. At that point the trolling just becomes too obvious.

Re:And when it fails this test too

[Krahar]

Apologizing for referring to the Christians' god as a he insults the English language just as much as saying "he or she" everywhere.

Re:And when it fails this test too

[Jason Kimball]

"What you call love was invented by guys like me to sell nylons. You're born alone and you die alone and this world just drops a bunch of rules on top of you to make you forget those facts." -Don Draper, Mad Men

Re:And when it fails this test too

[fyngyrz]

Mmmmm.... Nylons....

Re:And when it fails this test too

[agnosticnixie]

The gender neutral pronoun is singular they anyway (it's only a late 19th century phenomenon that people get pissy about not pretending "he" is gender neutral), no need to be apologetic.

Re:And when it fails this test too

[Jurily]

We can prove that the universe could have happened without God

Umm... how exactly?

The whole question is like P2P clients trying to figure out kernel internals and whether or not we're running in a VM, while others argue about the existence of the Programmer.

Re:And when it fails this test too

[Thanshin]

The gender neutral pronoun is singular they anyway

Singular they didn't mean it that way. Singular was talking about "singular they" instead of "it".

In singular our humble opinion, of course.

Re:And when it fails this test too

[OrangeCatholic]

Actually, check Wikipedia, it says 10^500. Wikipedia can be wrong, or imprecise, but they're not known for sarcasm.

It's under "Superstring Theory" below the yellow table.

Re:And when it fails this test too

[Anonymous Coward]

"What you call love was invented by guys like me to sell nylons. You're born alone and you die alone and this world just drops a bunch of rules on top of you to make you forget those facts. -Don Draper, Mad Men" --Michael Scott

Re:And when it fails this test too

[Haxamanish]

Well, propositional logic can be proven to be consistent (there are no contradictions) AND complete (all true propositions can be proven out of the axioms), so can first order predicate logic (in the PhD dissertation of Gödel, 1929).

To construct arithmetic out of logic, we however need second order predicate logic. Gödel (1930, published 1931) showed that axiomatic systems in second order logic are either incomplete (true non-provable sentences can be constructed) OR they are inconsistent (containing contradictions).

Re:And when it fails this test too

[OeLeWaPpErKe]

(incidentally you forgot the assumptions Godel made for 2), showing that for example, there are consistent maths, we just don't use them, as they're not infinite, and not "generally useful" whatever that means)

Additionally you forget the followup proofs, there are no consistent theories that can prove the consistency of "meaningful" mathematics (ie. +, -, *, /, n -> n + 1, ...). It's not just that the consistency of Peano arithmetic cannot be proved inside Peano arithmetic, it can't be proved, at all (in any meaningfull way : the only way to "prove" it is to accept it's correctness as axiom).

So really math is not consistent (if something cannot be proved, even if not actually disproved, you cannot reasonably say that it *is*, because it isn't). You can NOT say that math (arithmetic) is consistent, that's WRONG. You *can* say it's inconsistent (if you've proven, correctly, that a plane can never be observed flying, is it really such a stretch to say that it's going to crash when it's haning up in the air and time is frozen ?).

This is also not the sole problem with numbers. There are all sorts of unsolved paradoxes with even the natural number "infinite". (more general there are paradoxes that apply to any collection with infinite elements)

And this is talking about *just* natural numbers. rational numbers and, God help us, real numbers have much, much worse problems than mere doubts. It is known that rational numbers are inconsistent, and real numbers cannot be proven to even exist. There are no known ways to construct real numbers that are not simple extensions of rational numbers.

Re:And when it fails this test too

[Haxamanish]

So really math is not consistent (if something cannot be proved, even if not actually disproved, you cannot reasonably say that it *is*, because it isn't).

You are confusing "consistency" with "completeness".

Re:And when it fails this test too

[Anonymous Coward]

I predict when your 'dark strings' fail to explain everything, someone will come up with dark theories and dark unification.

can you really make something out of nothing

Just rabbits.

Re:And when it fails this test too

[ultranova]

Believing in String theory is a bit like searching for the Aether in 1900, or assuming the correctness of math before Godel (who proved math is not consistent, whoops)

Actually, Godel proved that maths is either not consistent or not complete. It's still correct, there's simply theorems that are true but can't be proven so.

Re:And when it fails this test too

[marcosdumay]

"You can NOT say that math (arithmetic) is consistent, that's WRONG. You *can* say it's inconsistent"

No, you can NOT say that it is inconsistent, and you can NOT say that it is consistent. The fact that you prove you can't say some A doesn't automaticaly makes NOT A true.

"There are no known ways to construct real numbers that are not simple extensions of rational numbers."

Having a bit of trouble with math, isn't you? What are you proposing to construct the real numbers of? Rational numbers? If so, that is just a tautology. You don't need to construct the real numbers, as you don't need to construct the natural numbers. You don't proff that math exists, that doesn't make sense (well, except if you define "exist" in some mathematical way, but then, you'll be just applying your definition).

Re:And when it fails this test too

[jamesh]

Apologizing for referring to the Christians' god as a he insults the English language just as much as saying "he or she" everywhere.

Given the insults that have been hurled at the English language by subsequent generations I think that it will understand (anthropomorphizing a language now???)

AC referred to God as an it. Doing that always reminds me of the psycho referring to his prey in silence of the lambs "it rubs the lotion on it's skin... or else it gets the hose again"

Re:And when it fails this test too

[Anonymous Coward]

Much power to slow cosmic expansion the dark side of the string has.

Re:And when it fails this test too

[hedwards]

Indeed, it's one thing for a test to come inconclusive, but when it comes back that the hypothesis was false, there's limited scientific responses to be made. You can conclude that there was a different mechanism involved or that it wasn't happening in the first place. The problem is that when you start asserting that the results would've been correct in some other reality which you can't directly observe, you end up with something that's about as scientific as any of the world's religions. Including that one, which nobody practices and pretty much everybody agrees is pure bunk.

Re:And when it fails this test too

[jamesh]

Yeah I re-read that after i'd hit the final submit and wished i'd worded it differently. The proof would require some assumptions that "the big bang happened because the big bang happened" and that "the rules of the universe are what they are because they are what they are". From that point on we can (in theory, eventually) prove that everything that happened since happened by following those rules.

The rules may also describe why the big bang happened too, but the reason for the rules being what they are is always going to be up for debate. Any theory that explains the reason that the rules are what they are is going to be untestable unless we take even more leaps of faith (and is going to define even more rules anyway)

Re:And when it fails this test too

[Anonymous Coward]

God is a trap.

Re:And when it fails this test too

[hedwards]

Indeed, then later on we had to deal with the closet bigotry brought in by the women's movement. A group so ignorant as to start making up meanings and context where really there is none. Personally I like it when women spell it womyn, it makes it clear who the bat shit crazy, bigots are so that I can avoid them. I mean really, woman is derived in part from the German word "man" which is sort of the rough equivalent of what the Brits say as "one." It's neither masculine nor feminine, singular nor plural and is used in all those cases where one requires a generic placeholder noun.

Which is why we have the words mankind and woman. And don't get my started on the rather tenuous story that is "history." Given that that one predates the English language I have a really hard time buying the common explanation that it's a portmanteau of his story.

Re:And when it fails this test too

[agnosticnixie]

Wow.

You a) failed linguistics, b) are an idiot and c) just built a huge strawman so you could burn it down. You must be proud of doing it in the kind of forum where, to boot, you will likely find like-minded idiots to applaud the strawman.

You do realize that the german word for woman is not derived from the german word for man, thus making your point even more ridiculous, right? Similarly, german "humankind" is Menschlichkeit, not "Mannlichkeit".

Re:And when it fails this test too

[Fred IV]

...because you don't fuck with love, love is a sociopath.

This is pretty much consistent with every relationship I've ever been in.

Re:And when it fails this test too

[maxwell demon]

Actually the God explanation replaces one question (Why does the universe exist?) with two (Why does God exist? And why did he make the universe?).

Re:And when it fails this test too

[OeLeWaPpErKe]

Having a bit of trouble with math, isn't you? What are you proposing to construct the real numbers of?

Well given that no-one's ever proven that the power operation generates consistent results when applied to infinite sets, I would actually prefer that you'd find something else to construct them of.

Besides, generally real numbers are constructed of the whole numbers. Something like R = Z x Z10, for example. And rational numbers are something like Q = (x, y), for x elem Z and y elem N0, with x and y having no divisors in common.

Re:And when it fails this test too

[OeLeWaPpErKe]

No I'm not. You are confusing the first and second incompleteness theorems.

Re:And when it fails this test too

[hedwards]

First off, I didn't make a typo. The word "man" is not the same as the word "Mann" is in German, which apparently you didn't know. Making it more than a little bit ironic that you're calling me an idiot when you didn't even know that.

Secondly, it's a legitimate follow up to assert that feminists get caught up in that out of bigotry and ignorance given that they aren't aware that the ultimate roots of it goes back ultimately to German via old English. Where it ultimately was derived from "wifman" as in basically a wife person, man meaning precisely the same thing at that point in time as it does now in German.

Or in other words if you're going to call somebody out for being an idiot it might help if you actually had some clue as to what it is the subject at hand.

Re:And when it fails this test too

[Anonymous Coward]

Where does the grandpost say anything about Christianity? Why do you assume jamesh had that particular version of God in mind? I thought it was self evident that a more general concept of 'god' was intended.

Re:And when it fails this test too

[agnosticnixie]

man in english comes from Mann in german, man is just "we"

Re:And when it fails this test too

[agnosticnixie]

Also nobody who uses "herstory" argues that it's because it has a tie to "his", it's obvious this word is a latin borrowing thanks to french, it's just a facetious way of saying "so this is history related to women/a woman".

Re:And when it fails this test too

[IICV]

We can prove that the universe could have happened without God but we can't prove he doesn't exist.

See, people say this a lot but it's just not true. Both the Christian Bible and common Christian belief make significant claims about their God, and none of them have been demonstrated in reality. For instance, a great many Christians believe in the power of intercessory prayer - that is, if someone is (e.g.) undergoing surgery, praying for them will help their health outcomes.

This has been tested and found to be not true.

The Roman Catholic tradition holds that, due to the miracle of substantiation, when you eat a specific cracker and drink some specific wine at a specific time during their ritual, it is literally and in reality transformed into the body and blood of Jesus Christ. This is blatantly false. In fact, my wife, who went to Catholic school from kindergarten on up, didn't realize until high school that she was supposed to literally believe in the miracle of transubstantiation - it just doesn't make any sense, even to children.

The Bible itself has a passage from Jesus saying "Again, I tell you that if two of you on earth agree about anything you ask for, it will be done for you by my Father in heaven. For where two or three come together in my name, there am I with them." (Matthew 18:19-20). This is, again, blatantly false in both aspects - we cannot do "anything" just by having two people ask for it. And as for the second part - conference rooms full of Christians are no different than conference rooms full of atheists, so that's clearly false for all detectable meanings of "there am I with them".

So while we cannot prove that vague, toothless, non-interventionist Deist gods do not exist (much in the same way that you cannot prove that the invisible intangible dragon in your garage that doesn't leave footprints doesn't exist), we can very much prove that the specific claims made by religion about God do not apply to any real thing that exists. In fact, so far, in terms of specific claims about reality, absolutely zero of the religious claims made about God have turned out to be true. This is, in fact, the most likely reason why apophatic theology has become more popular recently - if you don't make any positive, specific, testable claims about God, those mean and nasty scientists can't disprove them.

Re:And when it fails this test too

[Kevin Stevens]

String theory seems like modern day epicycles. Its extremely complicated, and every time someone finds something wrong, they add a whole new layer or three of extraordinarily complicated mathematics at it to fit the new data.

And it has yet to predict anything.

I was a physics minor, and used to read a lot about string theory, but by my senior year I had pretty much decided it was all a waste of time. I don't have any better theories to offer, but applying Occam's razor, I think a much simpler theory will emerge one day, and the legions of PHD's wasting their time with string theory will be out of a job. Even worse, when I was in school, string theory was the hot area, and just about every incoming grad student wanted to get involved in it. So much brain and manpower is being wasted on this, its really rather tragic.

Re:And when it fails this test too

[Bill, Shooter of Bul]

Umm... how exactly?

Well, ask him if he did. If he says yes, then he did. If no, then he did not.

Re:And when it fails this test too

[ndru82]

Thanks for this - I've been struggling for ages to figure out how Goedel's theorem might be applicable to the search for a Grand Unified Theory. If I understand what you're saying, then it does if either General Relativity or Quantum Mechanics involves the use of second order predicate logic. I'm guessing that because they both involve math that is somewhat more complex than arithmetic, that the answer to that is yes, but I'm not sure. So if we pretend that they both do involve second order predicate logic (or that at least one of them does), does it mean that the search for a grand unified theory is doomed? If you've got one theory (QM) that is consistent for small things but not complete (i.e. for heavy things) and another (GR) that is consistent for heavy things but not complete (for small things), does Goedel's theorem prove that neither GR nor QM can be extended to cover the case of small heavy things without sacrificing consistency? Or does it prove that the case of small heavy things is undecidable? Or is it just irrelevant?

Re:And when it fails this test too

[Antisyzygy]

What if the universe IS god?!?!? -Lame

Re:And when it fails this test too

[Anonymous Coward]

And if he does exist I bet string theory is giving him the best laugh he's had in centuries :)

Actually I have better laugh reading slashdot posts.
And as everybody here, I do not RTFA, even the ones about string theory

Yours Truly Anonymous #1

Re:And when it fails this test too

[Anonymous Coward]

1) Everyone can be wrong.
2) There is no way for someone who is wrong to actually know that he/she is wrong.
3) ...
4) No profit, only fear uncertainty and doubt!

Now run along and play with your proofs :)

Re:And when it fails this test too

[m50d]

It's not relevant. Goedel proves that it's possible to pose questions in the language of mathematics that are undecideable. But there's no reason to assume that you need the answers to these particular questions to do physics.

Re:And when it fails this test too

[geckipede]

General relativity already has this one covered. The universe is, to the best of our ability to measure it, very closely balanced between the positive energy that makes up all the matter it contains, and the negative energy of the tension of spacetime. If you could run the expansion of the universe backwards and collapse it all into a point again, you'd end up with nothing. The something we see around us came from exactly that - a grand total of zero on every scale you can measure.

Re:And when it fails this test too

[Coryoth]

Hmm, where is the -1 "Woefully misinformed" moderation when you need it.

It's not just that the consistency of Peano arithmetic cannot be proved inside Peano arithmetic, it can't be proved, at all (in any meaningfull way : the only way to "prove" it is to accept it's correctness as axiom).

Well this is just wrong. You can indeed prove the consistency of Peano arithmetic if you're willing to go outside it. Specifically you can use Gentzen's consistency proof, which doesn't "accept the correctness of Peano as an axiom" (but has other limitations). To add further weight to this, you may note that the Incompleteness theorems state that the system will either be incomplete (have unprovable truths) or inconsistent; Peano arithmetic is incomplete, for instance Goodstein's theorem is unprovable.

rational numbers and, God help us, real numbers have much, much worse problems than mere doubts. It is known that rational numbers are inconsistent, and real numbers cannot be proven to even exist. There are no known ways to construct real numbers that are not simple extensions of rational numbers.

This is just false as well. Real numbers are on firmer ground than the natural numbers as far as proof theory goes, since there is a complete and consistent axiomitization of the real numbers (in fact several) that aren't "constructed as an extension of the rational numbers". Since the axiomitization is simple enough, it doesn't fall afoul of the incompleteness theorems, and thus can be proved both consistent and complete.

Re:And when it fails this test too

[Haxamanish]

I agree with m50d that it is not relevant for the reason he gives above.

The Gödel theorems are interesting for the study of the foundation of mathematics and more specifically for the study of the relation between logic and mathematics. Using it outside that field is at least tricky, and more often than not crackpottery.

Out of a set of axioms (or out of a set of hypothesis) you use deductive logic to prove some theorems which are true if the axioms are true. The axioms together with the theorems form a theory. The question of completeness is: can we construct a proof for every true stament in that theory, or do there exist true statements which cannot be proven. The question of (in)consistentcy is: can we construct a proof for a false statement? All this is about the internal properties of a theory.

Now back to your question: relativity theory and quantum mechanics have different sets of axioms. The axioms of relativity do not lead to theories which are in contradiction with other theorems of the same theory (I am not sure about this for general relativity, there are however several sets of axioms for special relativity which have proofs of consistency*). I guess the same holds for QM**. The problem is: theorems of relativity are in contradiction with theorems QM, so this is a problem between two theories. The problem is that both theories are very solid and well-tested on their own right. A theory which tries to combine relativity and QM on a logical level is Branching Space-Time by Nuel Belnap.

* For axioms of special relativity, check: - Optical geometry of motion, a new view of the theory of relativity by A. A. Robb, 1911
- A theory of time and space by A. A. Robb
- The absolute relations of time and space by A. A. Robb, 1921
- Geometry Of Time And Space by A. A. Robb, 1936
- Orthogonality and Spacetime Geometry by Robert Goldblatt, 1987 (this is a first oder theory, so it is both complete and consistent - however it is not categorical
- Independent axioms for Minkowski space-time by John W. Schutz, 1997. This theory is of second order, so it suffers from the problems caused by the Gödel theorems.

** Check Quantum Logic by J. von Neumann (yes, the guy of the "Von Neumann Concept") and G. Birkhoff.

Re:And when it fails this test too

[david_thornley]

If God exists, I question the need and appropriateness for any adjective. It's a three-letter one-syllable word.

Re:And when it fails this test too

[Anonymous Coward]

God is love. You believe in love, don't you?

This is slashdot! We all know love doesn't really exist, it is just a fiction made up by the movie producers for the shows we download off the internet!

Re:And when it fails this test too

[Haxamanish]

Sorry, the second sentence of my last paragraph should read as "axioms of relativity do not lead to theorems" (in stead of 'theories'.)
The theory of Goldblatt is a "first order theory", logicians like that, because it is decidable. The theory of Schutz in categorical, the mathematician like that, even if it is undecidable.

Re:And when it fails this test too

[ndru82]

So far so good. But I guess the way I understand the objective of a grand unified theory, it involves the attempt to produce a set of axioms and theorems from which the important results in *both* QM and GR can be derived/proved. I'm as reluctant as the next person to extend Goedel's work into areas where it shouldn't really go (like a lot of the so-called new-age folk wisdom does). But I honestly think that if we spin the universe around and look at it from a different angle, Goedel's work might apply here. Obviously I haven't made a compelling enough case to persuade you or m50d, so I guess it's back to the drawing board for another few years. I also don't think I'm in agreement with making an impermeable barrier between physics and math. I mean, it seems to me that the language of physics *is* math. And for proof of that, I resort to xkcd. http://xkcd.com/435/

Re:And when it fails this test too

[JohnRoss1968]

The Cake Is A Lie !

Re:And when it fails this test too

[Haxamanish]

No I'm not. You are confusing the first and second incompleteness theorems.

OK, you made me read your post again.

(incidentally you forgot the assumptions Godel made for 2), showing that for example, there are consistent maths, we just don't use them, as they're not infinite, and not "generally useful" whatever that means)

There are indeed limited mathematics which are built upon first order logic and which are consistent and complete. They can even be infinite, if you allow for an infinite number of axioms by using an axiom scheme. But they are not strong enough to express arithmetics.

Additionally you forget the followup proofs, there are no consistent theories that can prove the consistency of "meaningful" mathematics (ie. +, -, *, /, n -> n + 1, ...). It's not just that the consistency of Peano arithmetic cannot be proved inside Peano arithmetic, it can't be proved, at all (in any meaningfull way : the only way to "prove" it is to accept it's correctness as axiom).

Using nothing but logic, one can build two kinds of mathematics which are strong enough (i.e. being of second order) to express arithmetics:
1) consistent (but incomplete) ones,
2) inconsistent ones - you say that all mathematics is inconsistent, but that is just plain wrong. Unless if one uses a paraconsistent logic to prevent the ex falso sequitur quodlibet, inconsistent mathematics is trivially complete, because all well-formed formulas would be true.
3) Gödel proves that the third kind, mathematics which are complete AND consistent do not exist.
3') One could consider mathematical theories of which we do not know if they are consistent or not as a third kind of mathematics, I don't know if anybody has ever constructed a mathematical system of which it can be proven that it is undecidable wether it is consistent or not (sounds like a nice project actually.)

So really math is not consistent (if something cannot be proved, even if not actually disproved, you cannot reasonably say that it *is*, because it isn't). You can NOT say that math (arithmetic) is consistent, that's WRONG. You *can* say it's inconsistent

You are confusing "consistency" with "completeness".

(if you've proven, correctly, that a plane can never be observed flying, is it really such a stretch to say that it's going to crash when it's haning up in the air and time is frozen ?).

I have no clue what you are talking about.

This is also not the sole problem with numbers. There are all sorts of unsolved paradoxes with even the natural number "infinite". (more general there are paradoxes that apply to any collection with infinite elements)

Yes, that's why there is a movement called finitism in maths.

And this is talking about *just* natural numbers. rational numbers and, God help us, real numbers have much, much worse problems than mere doubts. It is known that rational numbers are inconsistent, and real numbers cannot be proven to even exist. There are no known ways to construct real numbers that are not simple extensions of rational numbers.

Of course the existence of real numbers can be proved: take a triangle with a 90 angle & with both legs on that angle having a length of 1. Then the length of the third leg is a real number, SQR(2). It is easy to proof that SQR(2) is not integer nor rational. Now, defining and constructing real numbers is harder and there are non-standard mathematics which try to address the problems you hint at.

Re:And when it fails this test too

[Anonymous Coward]

God is love. You believe in love, don't you?

This is slashdot! We all know love doesn't really exist, it is just a fiction made up by the movie producers for the shows we download off the internet!

The RIAA should sue the MPAA, because I think the singers had it before the movie guys.

Re:And when it fails this test too

[Anonymous Coward]

Which is more interesting? Unprovable truth or undeniable falsehood?

Re:And when it fails this test too

[jamesh]

For instance, a great many Christians believe in the power of intercessory prayer - that is, if someone is (e.g.) undergoing surgery, praying for them will help their health outcomes.

This has been tested and found to be not true. [nytimes.com]

Any God worth his salt would deliberately sabotage those expirements "Though shalt seek to test MY existance? A pox on you!" :). The placebo effect isn't something to underestimate though. You have to know that people are praying for you to work of course.

Anyway, the bible is widely held, even by Christians as you point out, to be a bit of a fairy tale that nobody in their right mind would hold as the absolute truth (unless it suits their purpose to do so).

In the same way that string theory will be modified when tests prove false, so will the interpretation of God. You can prove the bible wrong but you can't prove the non-existance of God.

Re:And when it fails this test too

[jamesh]

What if the universe IS god?!?!? -Lame

Deep. You should write to Readers Digest. They have a page for people like you :)

Re:And when it fails this test too

[ps2os2]

Oh, No, a singularity!

Re:And when it fails this test too

[OeLeWaPpErKe]

Using nothing but logic, one can build two kinds of mathematics which are strong enough (i.e. being of second order) to express arithmetics:
1) consistent (but incomplete) ones,
2) inconsistent ones - you say that all mathematics is inconsistent, but that is just plain wrong. Unless if one uses a paraconsistent logic [stanford.edu] to prevent the ex falso sequitur quodlibet [wikipedia.org], inconsistent mathematics is trivially complete, because all well-formed formulas would be true.
3) Gödel proves that the third kind, mathematics which are complete AND consistent do not exist.
3') One could consider mathematical theories of which we do not know if they are consistent or not as a third kind of mathematics, I don't know if anybody has ever constructed a mathematical system of which it can be proven that it is undecidable wether it is consistent or not (sounds like a nice project actually.)

a) there is no proof that classes 1) and 2) are different (as long as we're talking about second order theories).

The problem that started with the choice axiom disaster is still unsolved.

One might even say that the concept of infinity is the problem. You can have a theory that allows a set to have infinite elements if and only if you present it as an axiom.

Re:And when it fails this test too

[Anonymous Coward]

math fail. the reals aren't a simple extension of the rational numbers. the reals come from the rationals after applying every possible simple extension and uncountably many transcendental extensions. or, you can do it the usual way and require every Cauchy sequence to have a limit point.

But..

[Entropy98]

However, given the second most common complaint, I can't help but wonder: which string theory?
 
Exactly, if this turns out to be false it won't disprove all string theory.
 
--
  windows media codec pack

Re:But..

[hedwards]

But if they accept that it disproves that theory, then they may get a boost in credibility. From being incompetent liars to being merely wrong. Which for string theorists would be a substantial step up in terms of actual credibility.

Not a test

[UnHolier than ever]

I scanned through the article and from what I see, they have made an equivalence between the maths used in string theory and the maths used in entanglement. This is interesting in itself, because this allowed them to port a result from string theory to entanglement theory, a result which was not known before and could be falsified.

However, this is like saying that the mathematical theory used to count apples harvested from an orchard (addition of natural numbers) is the same as the mathematical theory behind the algorithm the slashcode uses to count the number of comments below threshold (addition of natural numbers). It allows one to port result from ancient mathematics to modern applications without having to rederive everything from first principles; it does not mean that sub-threshold comments are, deep down, really made of apples.

Re:Not a test

[Anonymous Coward]

Nice try. Next time better try with cars rather tan apples.

Re:Not a test

[interkin3tic]

it does not mean that sub-threshold comments are, deep down, really made of apples.

Youtube comments would be oranges.

Re:Not a test

[CProgrammer98]

tan apples.

I prefer Green Apples personally

Re:Not a test

[kandela]

Are you comparing apples with oranges?

Re:Not a test

[noidentity]

However, this is like saying that the mathematical theory used to count apples harvested from an orchard (addition of natural numbers) is the same as the mathematical theory behind the algorithm the slashcode uses to count the number of comments below threshold (addition of natural numbers). It allows one to port result from ancient mathematics to modern applications without having to rederive everything from first principles; it does not mean that sub-threshold comments are, deep down, really made of apples.

I'm sorry, can you state this in terms of cars? Thanks.

Re:Not a test

[maxwell demon]

I'm sorry, can you state this in terms of cars? Thanks.

Your Fiat isn't a Porsche just because the motor of your Fiat is based on the same principles as the motor of a Porsche.

Physicist speaking

[JohnFluxx]

As a physicist, I do get a bit annoyed at the constant attacks on string theory in public media.

Let me just state a few points please:

  * We have Quantum Mechanics for the realm of the very small
  * We have General Relativity for the realm of the very heavy
  * Both of these theories fit observational data and work very well
  * The two theories contradict each other in the case of very heavy and very small object (e.g. tiny black holes)

So, we need a new theory that gives the same predictions at QM and GR in the realms that we can measure them. This is where string theory etc comes in. But we do not yet have experimental data for very heavy and very small objects. If you want to complain about string theory not being testable, then accept that your same complaint is going to apply to EVERY grand-unified-theory that we know of.

Conclusion
=========

If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative? The main scientific proponents against String Theory also just happen to have their own pet theories (e.g Quantum Loop Gravity) which are in an even worse situation.

If you complain about string theory taking so long, then what do you expect? It has taken 16 years just to do a single experiment (The LHC).

The only way we can make String Theory etc testable is by further research. If you dislike, please propose a better solution rather than just complaining.

TL;DR - People complain at string without proposing anything better.

Re:Physicist speaking

[Anonymous Coward]

You can tell someone is used to writing academic papers when they show a small bullet point list of statements (10% of the text), then reach a conclusion (another 10% of the text), then proceed to spend the other 80% of the text repeating the conclusion over and over again.

Re:Physicist speaking

[PolygamousRanchKid]

If you dislike, please propose a better solution rather than just complaining.

It's turtles . . . all the way down . . .

Re:Physicist speaking

[Krahar]

That's exactly opposite from usual academic papers.

Re:Physicist speaking

[OrangeCatholic]

So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

That's like saying, I know how to fly a plane, and I know how to drive a car, but neither skill applies to flying cars, which I've also never seen.

But they must exist, right??

Re:Physicist speaking

[Mikkeles]

Since I have a physicist here :^)

Since string theory cannot be distinguished from , e.g., QM (i.e., string theory is untestable), does that not also imply that QM cannot be distinguished from string theory (i.e., QM is untestable)? So why is QM given precedence?

Re:Physicist speaking

[Capt'n Hector]

I think the public media attacks string theory on the grounds of its impossibility to test because they don't know any better. Those of us in physics and math have very real and strong arguments against string theory that have little to do with testing.

Re:Physicist speaking

[addsalt]

If you dislike, please propose a better solution rather than just complaining.People complain at string without proposing anything better.

The major concern is not that people continue to investigate string theory, but that it is done en masse at the expense of following competitive theories. The string theory trail has certainly gotten colder, and it is time to start investigating other alternatives. I'm all for a few physicists beating the dead horse because it just may come back to life, but we don't need everyone doing it.

Re:Physicist speaking

[Anonymous Coward]

If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative?

Which by an astonishing coincidence is the same argument in favor of god-did-it theory.

Re:Physicist speaking

[Anonymous Coward]

I am assuming your experience is not on Philosophy papers...

Re:Physicist speaking

[CheshireCatCO]

So, we need a new theory that gives the same predictions at QM and GR in the realms that we can measure them. This is where string theory etc comes in.

Not really. Last I checked, String Theory hasn't made any useful predictions about systems like this. No one has managed to fold gravity into a Theory of Everything yet, unless I missed an important update. (Feel free to correct me if I have.)

TL;DR - People complain at string without proposing anything better.

A theory that offers no new powers of explanation and prediction is itself no better than the pre-existing paradigms. Until String Theory can show itself to have some value (leaving aside the issue of whether it's the best such model), there's no reason to cling to it. "Better" implies that ST was somehow useful to begin with.

Re:Physicist speaking

[Nerdfest]

Did you just use a car analogy in an article about testing string theory?

Re:Physicist speaking

[Anonymous Coward]

Ok, I don't know much about string theory. lol.
I'm just not happy about the approach. It seems so arbitrary to me. I read a bit about some years ago. It seems to leave like it room for almost arbitrary universes and you need to make it fit to our universe by finding the right parameters, calabi-yau space or whatever.
Seems to me like some mathematician said: 'Let's try this.' and since then thousands of scientists are working on it to make it fit by bruteforce ... mmmh, 1-dimensional strings don't work, lets try n-branes etc ...
Well, maybe I see it totally wrong. I'd like to hear, how it really is.

I'd be more happy, if there was a theory that needs less tuning. Someone sensing the connection between quantum physics, gravity/relativity etc. and coming up with something that explains it all and then the already known formulas fall into your hands without much tuning. Ok, you don't always get what you are wishing for. ^^

( The latter approach is something I'm following out of fun. If I write a bunch of interesting phenomenons and some physical laws down plus my thoughts about them, then I intuitively sense that this stuff is all related in a certain way and I feel roughly, how, quantum mechanics and relativity suddenly make 'sense' when seen in a context, but I'm not sure, how to mathematically approach it yet. My main problem is to get time and space out of my head as a stage. There not more fundamental than anything else imho. It's just difficult to abstract from time and space in your mind, trying to see thing on a more fundamental level. )

Re:Physicist speaking

[m50d]

Except you're talking about the universe here. We may not have built a flying car, but it is possible to have a very small black hole. Unless you're suggesting that it isn't possible, but that's really just another theory that you're going to have to justify in the same way.

Re:Physicist speaking

[Anonymous Coward]

If you were a real physicist you'd know that the LHC has nothing to do with string theory.

Re:Physicist speaking

[Anonymous Coward]

Like the person said, "That's exactly opposite from usual ACADEMIC papers."

Re:Physicist speaking

[Thanshin]

does that not also imply that QM cannot be distinguished from string theory?

That's what I've always said!

The quality manager didn't find it funny.

Re:Physicist speaking

[thesandtiger]

TL;DR - People complain at string without proposing anything better.

What ever happened to "we don't know"?

You can criticize a theory without proposing anything better if you don't have a theory yourself - because you can point to flaws in the other theory. Observations that seem to go against the theory, the impossibility of falsifying the theory, etc.

For example, I can point at "intelligent design" and say it's a bad theory because it is not falsifiable and I don't have to offer an alternative theory of abiogenesis because I'm not saying "my theory is better" but merely "that theory is not scientific."

I can say "God gets involved when we talk about very small, heavy things, because God is just fascinated by those things, too, and that's why we find it so difficult to bridge the gap between our two major ways of understanding the universe when it comes to those" and it is *every* bit as good as string theory because it's *exactly* as testable, and it's based on *exactly* as much evidence as string theory is based on.

"I don't know, but I know that your theory isn't scientific, so until you can make it testable, I'm going to treat it as nothing more than speculation" is a PERFECTLY acceptable starting point.

Re:Physicist speaking

[MartinSchou]

So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

We know that very very small objects exists (subatomic particles). We also know that very very massive objects exists (stars).

Usually the two are linear. The smaller an objects, the less mass it has.

Unfortunately there IS a crossover point. There are objects with a density of approximately 370,000,000,000,000,000 kg/m^3. These can be modeled with regular physics for 'large' objects, and they affect things far outside the realm of Quantum Theory (i.e. you can orbit a human around such an object). Get too much above this point though, and you end up with an object that seems to be smaller than the smallest subatomic particles (Quantum Theory) yet affects things that are far outside the realm of Quantum Theory - these items are commonly known as black holes.

How do they work? Well ... they're insanely massive. And they're really tiny. As to what goes on inside them ... we've no clue. We can't use Quantum Theory because it's too massive, and we can't use regular physics, because it's too small.

Re:Physicist speaking

[thesandtiger]

Forgive the self reply - I wanted to amplify:

Saying "don't criticize a theory unless you have a better one" is actually counter productive because it encourages the championing of pet theories rather than the actual doing of science.

Re:Physicist speaking

[alaffin]

Just to add to the crowds already responding to this, but my real questions "why"?

Now you'll have to pardon me, because I'm not a physicist. I won't pretend to know all that much about string theory. For that matter I don't know all that much about quantum mechanics or general relativity either. Enough to keep my geek card valid, but that's about it. But I don't think my ignorance of the topic invalidates my question, as it's more of a question of methodolgy than actual science.

As I understand it (and as you have presented it) physicists have (at least) two models of the universe. QM handles really tiny things. GR handles really massive things. But neither is a perfect model - the so-called "Theory of Everything" or what have you. They each break down as they approach the domain of the other.

Now obviously, if we want to truly understand the universe we must reconcile these two conflicting theories. String theory does it nicely (or not so nicely, depending on your point of view) but in all honesty why do we have a theory for explaining the behavior of something we can't observe? At this point you're just throwing some numbers around - which is fine if you're a mathematician, but not so fine if you're a physicist.

Before the math folks in the audience get up in arms - I love you guys, I really do. And I'm sure the work that you're doing with category theory or whatever will benefit the world greatly one day. But, in the world of science you're the tool-makers. Or, since this is Slashdot, you're the auto-makers. You don't actually drive around in one of those nice, expensive Italian sports cars (well, maybe some of those cryptographers who work for the government) but none of us would be driving at all if you weren't doing your very important work.

Back on topic. You're a physicist. It's your chosen task in life to unlock the deepest secrets of the universe. Hell, you're ultimate goal is so much more than just unlocking the secrets. You should be looking at creating your own, new universe. And you do that by understand the rules and laws that govern our universe.

But string theory doesn't do that. String theory is a universal law looking for a universe to impose itself upon. We think - well, you think (you being all physicists) - that this theory will work, that it will fit two pieces of the puzzle together. But, at least as far as I understand it, it's bad science to run around looking to prove a theory you just came up with. Theory should be based on observation, not obscure eldritch maths. And since we haven't observed anything yet, we shouldn't have anything beyond a basic, testable, hypothesis. Otherwise we're in danger of limiting our vision. What if string theory continues to fail every test it is subjected to? When do we say "hmm... this isn't working - maybe it's time for a new theory". We tend to put blinders on when we get attached to something.

Maybe it's time we set string theory aside until it's concievable to observe such things. Otherwise we may come to regret it.

Re:Physicist speaking

[Anonymous Coward]

I am sick and tired of people simply not trying. I constantly hear the excuse is that it's just too hard. So, people screw around with string theory, or work on other things, rather than attack the hard problems. If you are willing to make a lot of unjustified assumptions you can make lots of nonsense calculations. e.g. that gauge invariance, or gravity, or Lorentz invariance are exact symmetries and we've got them exactly correct in field theory, and our formulation holds to arbitrarily high energies. AdS/QCD is perhaps the most interesting to come out in the last decade, and it's a conjectured relationship between two theories that are definitely not realized in nature. Thousands of papers screwing around with a theory that is demonstrably not realized in nature. Any predictions coming from it cannot be related to the real world. String Theory has had 50 years to make a prediction. If you spend your entire career on a topic and do not do anything that has any prediction or explanation of any experiment, you cannot call yourself a physicist, and are not using the tools of physics (e.g. experiments). Instead you can only be a mathematician, and the tools you must use are proofs. String Theory instead is full of "physics inspired" ideas which are neither mathematically rigorous, nor testable, and therefore are in the doldrums with fields like Anthropology and Sociology, with no mechanism to select good work from bad. It's just a lot of noise. No attempt is made to attack the fundamental problems shared by string theory and field theory, they're "too hard". On the other hand there are 10^500 vacua. That's more than 10^500 papers with still no progress, so it's a noise (and citation) machine, rather than a real theory.

Conformal Field Theory is a fine mathematics topic, but it's not physics, and neither is String Theory, until an experiment is performed. 50 years is enough. Time for new ideas. You'll be hearing from me.

Re:Physicist speaking

[maxwell demon]

Since string theory cannot be distinguished from , e.g., QM (i.e., string theory is untestable), does that not also imply that QM cannot be distinguished from string theory (i.e., QM is untestable)? So why is QM given precedence?

Because string theory builds on QM. Therefore there are only three logical possibilities:

• Both QM and string theory are right.
• QM is right, but string theory is wrong.
• Both QM and string theory are wrong.

Note that this does not include your suggestion (ST right, but QM wrong). Given that experimental data overwhelmingly confirmed QM, of those three options only two remain, which only differ in the question whether string theory is right.

Re:Physicist speaking

[syousef]

>If you complain at string theory, then PLEASE state what you are proposing.

Turtles all the way down! Everybody knows that!

Re:Physicist speaking

[matunos]

MAGIC MAN DONE IT!

Re:Physicist speaking

[rapierian]

Interesting...As a physicist, I attack string theory.

My main problem is it's method of development. Unlike most of the rest of the theories in the history of physics, string theory seems to be developed with a preconceived notion about what the solution is. If you look at the rest of the physics world, the theories were developed after data came in and partially upset the previous theory, and they were developed in accordance with the new data.

Re:Physicist speaking

[Anonymous Coward]

This. A thousand times, this. The above 'physicist' has scant knowledge of scientific method if ''you can't think of anything better!'' is supposed to count as an argument. That's exactly the reason we DON'T trust string theorists.

Re:Physicist speaking

[OrangeCatholic]

>Unless you're suggesting that it isn't possible, but that's really just another theory that you're going to have to justify in the same way.

That's quite easy. Black holes are formed when gravity overwhelms all other forces, which I take to mean nuclear strong/weak forces. (If you look at a neutron star, it's density is the same as a nuclear density.)

In everyday life, it takes about 7000 cubic kilometers of volume before you have enough space to pack in enough mass to do this (calculated from a 12km schwarzchild radius typical of a neutron star).

And you want to do that on a smaller scale? Where oh where will you get the gravity?

Re:Physicist speaking

[DougBTX]

I think that quantum mechanics can be distinguished from string theory. Your computer probably wouldn't run so fast without an understanding of QM, eg, your computer running is a test of QM.

Re:Physicist speaking

[Saib0t]

As a physicist, I do get a bit annoyed at the constant attacks on string theory in public media.

Let me just state a few points please:

If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative?

What kind of scientist are you? It doesn't matter if I can offer an alternative suggestion or not.

The use of "complaining" is to determine the validity of the theory. You can't test it, you can't determine if it's true. Simple enough for you?

If I were to say that invisible pink unicorns like small massive objects, you'd have every right to tear my suggestion apart without having to offer an alternative, that's the way it works...

Re:Physicist speaking

[plumby]

If you complain at string theory, then PLEASE state what you are proposing.

I never get this line of argument. Surely if you've got evidence that demonstrates a particular theory is clearly wrong, it's better to flag that up even if you've not got any specific alternative. If nothing else, it should encourage others to stop wasting their time pursuing something that's clearly wrong.

I'm not saying that string theory is wrong (I'm not a theoretical physicist, and I've got no particular views on this theory), but the principle of not being allowed to point out that something is wrong unless you know what the right answer is always annoys me.

Re:Physicist speaking

[tenco]

How do they work? Well ... they're insanely massive. And they're really tiny. As to what goes on inside them ... we've no clue. We can't use Quantum Theory because it's too massive, and we can't use regular physics, because it's too small.

How do you know they are tiny? Sure, GRT predicts a singularity. But has anyone ever actually measured the size of a black hole's mass distribution beyond the event horizon?

Re:Physicist speaking

[Sulphur]

There are only three Ninja Turtles.

Re:Physicist speaking

[OrangeCatholic]

>you end up with an object that seems to be smaller than the smallest subatomic particles

I think the important word here is "seems". Black holes were discovered when Schwarzchild found a way to get 1/0 in Einstein's field equations.

From then, it's been 95 years of madness perpetuated by people who have never seen a "limit" drawn on a graph.

Re:Physicist speaking

[Anonymous Coward]

Hey, my wife majored on philosophy, and she promises this will be the year she gets a job!

Re:Physicist speaking

[Taibhsear]

I think the public media attacks string theory on the grounds of its impossibility to test because they don't know any better.

If that were true, why wouldn't they do the same to religion or existence of a god?

Re:Physicist speaking

[radtea]

People complain at string without proposing anything better.

Not so. There are a variety of more-or-less heuristic alternatives to string theory, they just don't have supporters that are quite so grandiose and arrogant as string theorists.

The problem with string theory is that it is uniquely hard to build models of low-energy systems using any of its variants, which is funny because it has been applied in pure form to various solid-state systems. But due to extremely high string tension (or equivalent parameter) that is necessary in the "theory of everything" string theory it has to be reduced to some low-energy approximation to describe the world we see, and no one knows how to do that, certainly not uniquely.

This paper is describing an incredibly interesting application of string-like mathematics to a quantum entanglement problem, but unfortunately it still falls within the domain of the famous XKCD on the topic, where when asked what the consequences of his idea that the world is made of tiny vibrating strings the guy replies, "I dunno." It is simply weird that the isomorphism exploited in this paper exists, but whether that means something deep or something trival is still up for grabs.

Regardless, it is simply not the case that every GUT would have the same problems as string theory, for which the grand unification scale is absurdly high. There are non-string theories floating around out there that will be knocked off by the LHC, for example, because they depend on much lighter "X" particles.

Lisa Randall's book "Warped Passages" gives a nice introduction to some of these theories that would even be accessible to a non-physicist like yourself.

Re:Physicist speaking

[CheshireCatCO]

So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

Um, the cross-over objects exist. Grandparent poster is wrong, you don't need small black holes; any singularity has the problem of needing quantum mechanics and general relativity to describe it. This is true of the inner workings of any black hole, for example. (No, we can't get data from one, as far as we know.) Or, just fer instance, the Big Bang. There is a surprising amount of interest in modeling that one.

Does that make more sense?

Re:Physicist speaking

[apoc.famine]

Thank you. That made me laugh, in part because it struck so close to home. I came to post the same, albeit less funny message.

As a physicist, I think string theory represents a lot of interesting math, but no interesting science. I have some pretty serious doubts that it will ever amount to anything useful.

Re:Physicist speaking

[hedwards]

You know what, just for that, from now on I'm going to call it "String Hypotheses" until such a time as somebody actually successfully falsifies something. And then comes up with a test that seems to work. It doesn't matter whether anybody has anything better to go on, the fact is that until they start to falsify things when they fail, it isn't science, it's a weird religious fetish for atheists.

Re:Physicist speaking

[ByteSlicer]

If you dislike, please propose a better solution rather than just complaining.

Here you go...
(I'm not a theoretical physicist, but the fractal space-time that seems to emerge from CDT makes a lot more sense to me than 11-dimensional strings and branes)

Re:Physicist speaking

[radtea]

So wait, we have two theories that describe different realms and no data for the intersection of the two realms, but people are trying to come up with a theory for the intersection?

We have two theories that describe different realms (although not the realms mentioned in the summary) and we have a known isomorphism between the mathatical description of one of them in stringy terms and the behaviour of the other. This paper extends that isomorphism into a currently intractable area.

So it's more like saying you know that people who can drive Fords can also drive Toyotas, but Toyota has just come out with a new model that none of the Toyota drivers can handle, so why not give it to a Ford driver and see how they do?

It's bound to be an interesting experiment even if it ends with a heap of smoking metal.

String theory is a vast sprawling body of mathematics that has found application far afield of its original domain of high-energy physics and grand unification, particularly in solid state physics where various "string like" phenomena can be found. This work is applying the mathematics of string theory that were developed for classifying black holes to classifying types of four-particle entanglements. That's an extremely curious correspondence, even if it just turns out to be a coincidence.

The problem is that there are disingenous twits who point to string theory's successes far from anything to do with grand-unified string theory, which is what most people mean when they hear "string theory" and claim that "string theory" is makes testable predictions, which is false. No grand-unified string theory has ever made a testable prediction, but this paper is describing something that is quite a lot closer to that than anything we've see so far.

Re:Physicist speaking

[maxwell demon]

But isn't that difference just academic? :-)

Re:Physicist speaking

[maxwell demon]

You mean, a string of turtles?

Re:Physicist speaking

[Dhalka226]

If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative?

As I read your post, and especially this part, I was struck by how wrong I consider this sentiment.

Science is about the search for answers, the search for truth, and we have spent the better part of our history refining what we think to be important in that search. "I don't know what the answer is, but that is wrong" is and should always be a perfectly valid answer.

The reason this line in particular got to me is because it struck me as the sort of response one gets when arguing against religion with a theist. They're not satisfied that you have strong responses suggesting what they believe might be wrong*, they insist that you have the answers to all things and if you don't, they walk away smugly and declare their beliefs to be superior. It's God of the gaps in argument form.

In fact, I think it is similar to this situation. God can not be disproven according to our scientific standards, because he is not falsifiable (what if there is a God who doesn't want you to discover him?). That doesn't mean he exists or that he doesn't; it means disproving him is not scientific. If String Theory can not be falsified, can not be repeatedly verified, then I feel it is right to criticize it on those grounds. Hell, maybe it turns out to be exactly and perfectly correct but it is not, at least right now, correct from a scientific standpoint. If what's going on in this article changes that going forward, great! I'm all for a (slightly) more definitive answers, one way or another. If not, then perhaps some extra energy needs to be expended in making it a proper scientific theory. Maybe that will even make it more solid and robust going forward. And if that perception is incorrect (I readily admit that my mind can not wrap around these theories) then that's what neds to be fixed.

Not having all the answers doesn't make criticisms wrong or even worthless.

On a somewhat related note, having one's own pet theory doesn't make talking against something else wrong. It's right or wrong on its merits, not its circumstances. Another way of saying "happen[ing] to have their own pet theories" is "has a theory they think fits better." They may be right or wrong, but if they didn't believe that their theory was better it wouldn't be their theory.

* Please, let's not get into a debate about religion here!

Re:Physicist speaking

[John Hasler]

...but the principle of not being allowed to point out that something is wrong unless you know what the right answer is always annoys me.

The critics he's complaining about aren't pointing out anything that is wrong. They are complaining that the string theorists haven't made any predictions that they can test. That doesn't seem like a good reason to try to tell the theorists to stop looking for testable predictions.

Re:Physicist speaking

[John Hasler]

If you look at the rest of the physics world, the theories were developed after data came in and partially upset the previous theory, and they were developed in accordance with the new data.

Doesn't the incompatibility of QM and GR constitute such an upset?

Re:Physicist speaking

[OrangeCatholic]

>Does that make more sense?

It makes sense that you believe in singularities as a concrete, physical object, rather than as an abstract inflection point that produces other, more realistic objects.

Re:Physicist speaking

[oldhack]

Pick one that doesn't belong with the others:

- Flying car
- String "theory"
- Packet of Cool Ranch Doritos, family size
- Dukem Nukem Forever

Re:Physicist speaking

[CheshireCatCO]

You don't need a mathematical singularity to create the problem. You just need a highly compact, near-singularity. Both the Big Bang and the interiors of black holes qualify, unless QM or GR is wrong.

Re:Physicist speaking

[plumby]

Ah - that's a different matter, and I agree with that. Claiming that something is wrong simply because it hasn't been proved is just silly.

However, I do regularly come across the idea that you shouldn't tell someone they are wrong (even if you can show that they are wrong) unless you've got a better suggestion as to what is right, and that's pretty silly as well.

Re:Physicist speaking

[Anonymous Coward]

From then, it's been 95 years of madness perpetuated by people who have never seen a "limit" drawn on a graph.

Wow, you really are pretentious, aren't you? You're belittling the work of people who clearly know more math than you do because you don't like the results, while claiming a superior understanding of the material.

You're not even aware of the fact that black holes have been observed, are you? Or are you just preferring to ignore contrary evidence so you can continue perpetuating your smug sense of righteousness?

Re:Physicist speaking

[Anonymous Coward]

TL;DR - People complain at string without proposing anything better.

God did it!

wait that sounds like trolling.

A magic pony did it!

Re:Physicist speaking

[Anonymous Coward]

Cobain yourself.

Re:Physicist speaking

[fredrik70]

depends, is this pascal strings we're talking about?

Re:Physicist speaking

[rmstar]

The only way we can make String Theory etc testable is by further research. If you dislike, please propose a better solution rather than just complaining.

Here is a better solution. Stop beating up that dead horse, abandon the field and do research in something that actually has a better chance of producing interesting, meaningful, and perhaps even useful results. How about that?

Re:Physicist speaking

[bcrowell]

If you complain at string theory, then PLEASE state what you are proposing. What is the use in complaining when you have no alternative?

Why does there have to be an alternative? You've done a nice job of laying out the reasons for extreme pessimism about achieving any theory of quantum gravity, basically because we can't probe the Planck scale experimentally. I would propose not to fund any further research into quantum gravity for the foreseeable future.

If you complain about string theory taking so long, then what do you expect?

I expect to go to my grave before there is a theory of quantum gravity.

It has taken 16 years just to do a single experiment (The LHC).

That's a totally bogus analogy. The LHC is virtually guaranteed to tell us some new objective facts about the laws of physics. It will either find the Higgs, which would be an important confirmation of the standard model, or it won't -- in which case all hell will break loose, and it will be very exciting. String theory, on the other hand, is not guaranteed to be anything but a dead end. So far, it is a dead end.

The only way we can make String Theory etc testable is by further research. If you dislike, please propose a better solution rather than just complaining.

I would propose no longer funding research into string theory. Anyone who has gotten used to having funding for a research program would love to have funding for further research. That doesn't mean that they should be guaranteed further funding if their field turns out to be a failure.

Re:Physicist speaking

[IRWolfie-]

As a physicist I am annoyed at people regarding this string idea as a theory. It dilutes the meaning of the word theory.

Re:Physicist speaking

[JohnFluxx]

We'd have to get into a pretty technical debate to argue about whether the string theory trail has gone cold, and IMHO it would still come down to opinion.

As other people said here, research into string theory is not wasted - it has produced volumes of useful math.

I think it's very reasonable to discuss the proportion of funds into ST and QLG etc, but that's a far cry from the current emotional language and conversation that goes on currently.

Re:Physicist speaking

[fadethepolice]

I can't believe this got modded up to five, it has to be the lamest metaphor I have read in a while. THERE IS NO CAR THERE IS ONLY A PLANE. We do not have two different objects, just two different ways of describing one object, reality. So it is nothing like what you are saying. Since there is only one object there has to be one way of describing it.

Re:Physicist speaking

[m50d]

So you can't create them in everyday life, sure. But it would seem to just be a matter of engineering to forcibly squash some matter that small; if you want to say the fundamental laws of physics make it impossible, you're going to need more than that.

Re:Physicist speaking

[WrongMonkey]

It's called PR backlash. There are people in the string theory community, such as Brian Greene, who have promoted string theory above and beyond the recognition that it really deserves. When string theory didn't immediately deliver on tangible breakthroughs (the way GR and QM did), people start to grumble and wonder if you're pulling a fast one. And your fellow scientists aren't going to be quick to defend you because their own work (which probably does have a more substantial, immediate impact) gets drowned out in comparison to string theory. Also because physicists have a reputation of being prima donnas.

Re:Physicist speaking

[JohnFluxx]

One of the reasons that String Theory is so popular is _because_ gravity comes up straight away, without assuming it. That is why it is so popular.

> A theory that offers no new powers of explanation and prediction is itself no better than the pre-existing paradigms. Until String Theory can show itself to have some value (leaving aside the issue of whether it's the best such model), there's no reason to cling to it.

"Cling to it" meaning what? If another idea came along and did better than String Theory, people would switch to it.
People are researching it to try to find "new powers of prediction".

Re:Physicist speaking

[JohnFluxx]

I know you are joking, but I did mean:

"Please state what you are proposing that scientists should do instead of researching such theories"

rather than

"If you can't give an alternative theory then string theory must be true"

Re:Physicist speaking

[CheshireCatCO]

Quantum Mechanics can (and has) been tested. Repeatedly. What makes String Theory different is that while it includes QM, it doesn't generally offer any new predictions. A theory that offers nothing new (neither predictions nor a paradigm that is either easier to work with or provides more insight) is useless. If all ST can do is reproduce QM exactly, it's at best a more complicated what to do the same math.

(That said, I seem to recall ST making a new, testable prediction in the cosmological constant. I also seem to recall it being way, way, way off. But I may be misremembering that.)

Re:Physicist speaking

[JohnFluxx]

I fear that my wording was too ambiguous.

I was not stating that we should accept String Theory as a Theory, or as the truth or anything.

I was asking - please propose what scientists should do instead?

I.e. if you criticize string theory, then what do you want the scientists to do instead? Just give up and go home and do no more research?

Re:Physicist speaking

[JohnFluxx]

Yes, my wording is off.

I meant "Please state what you are proposing scientists to do instead of researching these currently untestable theories"

Re:Physicist speaking

[JohnFluxx]

Yeah, I hate my wording. I meant:
"Please state what you propose scientists should do instead"

rather than:

"Please state what theory should be taken as True instead"

Re:Physicist speaking

[JohnFluxx]

Ah, the usual "But my pet theory is better! Why does nobody listen to me!"

Re:Physicist speaking

[DerekLyons]

So, we need a new theory that gives the same predictions at QM and GR in the realms that we can measure them. This is where string theory etc comes in. But we do not yet have experimental data for very heavy and very small objects. If you want to complain about string theory not being testable, then accept that your same complaint is going to apply to EVERY grand-unified-theory that we know of.

And this is where your logic fails, you've pulled off the old trick of proving 1=2 by introducing a false assumption. In this case, the assumption that experimental data is required to create testable predictions.
 
Further falsifying your hypothesis is the presence of data in the realms other than very small and very heavy - the realms string theory is also supposed to be able to explain. (At least according to some proponents.)
 

TL;DR - People complain at string without proposing anything better.

Horse shit. Noting the flaws in your theory in no way burdens me with the requirement to produce something better. That's new age touchie-feelie crap.

Re:Physicist speaking

[JohnFluxx]

> I would propose not to fund any further research into quantum gravity for the foreseeable future.

Well that's certainly one suggestion. Seems pretty short sighted to me though to just stop funding any areas you don't expect immediate benefits from.

> It will either find the Higgs, which would be an important confirmation of the standard model, or it won't -- in which case all hell will break loose, and it will be very exciting

It would be important if we do find the Higgs, but it would hardly cause all hell to break up. Everyone expects to find the higgs, and it wouldn't give us any new insights.

Re:Physicist speaking

[CheshireCatCO]

One of the reasons that String Theory is so popular is _because_ gravity comes up straight away, without assuming it. That is why it is so popular.

No, it doesn't. No one has yet managed to merge gravity into the quantum paradigm successfully. Unless I missed a major, major breakthrough in the past few years since graduate school.

"Cling to it" meaning what? If another idea came along and did better than String Theory, people would switch to it.

You're clinging to this idea that ST has provided any value so far. It hasn't. It's an intriguing idea that may pan out and pay great dividends if it does. But it has yet to give us any new power of prediction. So there's really nothing to be "better" than. It hasn't yet shown itself to be better than QM yet, so I don't know why you think it's the theory to beat.

Re:Physicist speaking

[sco08y]

Did you just use a car analogy in an article about testing string theory?

You can't prove it either way.

Re:Physicist speaking

[OrangeCatholic]

There's no evidence of singularities, you fell right into the trap again. Black hole if you will. Which do, remarkably, exist.

Re:Physicist speaking

[Anonymous Coward]

Take a look at: http://www.terrafugia.com/

Re:Physicist speaking

[Anonymous Coward]

Noone knows WTF to model. It's probably when photons gain mass or something.

Re:Physicist speaking

[minogully]

4 actually...

Donatello
Raphael
Michaelangelo
Leonardo

Re:Physicist speaking

[John Hasler]

Trying to tell theoretical physicists what to study makes about as much sense as trying to tell Free Software developers what to work on.

Re:Physicist speaking

[bcrowell]

>>It will either find the Higgs, which would be an important confirmation of the standard model, or it won't -- in which case all hell will break loose, and it will be very exciting

>It would be important if we do find the Higgs, but it would hardly cause all hell to break up. Everyone expects to find the higgs, and it wouldn't give us any new insights.

What I said was that if they don't find the Higgs all hell will break loose. There are some pretty solid model-independent arguments that something new has to happen in this energy range. If it's not the Higgs, it's got to be something else, and the other "somethings" are all pretty exotic and not part of the standard model.

Re:Physicist speaking

[Anonymous Coward]

So are you arguing that singularities as formal "zero volume" entities don't exist? Because anyone who knows anything about this knows that you don't need infinitely small things to require a joint QM/GR theory. (As far as I know, most physicists don't really think that a true singularity exists.)

Then again, since you were arguing against Schwarzchild, that can't be what you meant. Schwarzchild's work had nothing to do with "1/0", but you'd know that if you'd bothered to educate yourself on this topic.

Re:Physicist speaking

[Anonymous Coward]

The thing is, we've had years and years of 'string theory will solve all our problems' and 'string theory is the only game in town' from people who should know better. String theory failed at what it was originally supposed to do: strong interactions. Then QCD (a theory that would have been completely ignored if string theorists had their way) came and worked, and string theorists realized that they had a spin 2 particle.

The emotional language is from people who've seen their research programs killed because string theory got all the funding, and have been told that their research is useless because it's not strings. String theorists don't acknowledge any of the other attempts at finding a quantum theory of gravity and have pathetically little exposure to any of them - you yourself juxtapose even the words in the name of Loop Quantum Gravity.

Alternative theories of quantum gravity have been waved away for years by string theorists claiming that they have the right theory, and they don't even bother to try to understand anything else. They ignore the idea of background independence. They know nothing of Causal Set Theory, Causal Dynamical Triangulations, Graphity, Spin-Foams or Loops, but somehow claim that they have the only path to a theory.

That's why we get emotional. Because our careers have been terminated for a hypothesis that has gone nowhere. Because a mediocre string theorist has a much easier time getting a job than a great loop theorist. And yet string theory has given us no predictions, no new physics, and not even a hint of testability.

Re:Physicist speaking

[Anonymous Coward]

You don't even need that - GP hasn't got a clue about physics. You can just take a regular BH and wait for hawking evaporation to make it nice and small (Planck scale) for you. Of course, a full understanding of Hawking radiation would require a quantum theory of gravity too, but what the hell.

Re:Physicist speaking

[plumby]

That's OK then. Sorry for jumping down your throat - my interpretation of your original comment just hit a particular nerve for me.

Re:Physicist speaking

[TheTurtlesMoves]

Turtles for the win!

Re:Physicist speaking

[TheTurtlesMoves]

You know what they use to say about --well all that math we now use for quantum physics.

Re:Physicist speaking

[SEE]

Here's what it looks like from the outside:

It is quite possible that, given how quickly life appeared on Earth, it was deliberately seeded here by intelligent aliens. This theory is, in principle, testable; if it is true, a concerted search of the galaxy should show evidence of these aliens. However, there is no serious effort spent by biologists working out the implications of this theory, because it is currently so untestable that it's a waste of time. There are speculations in popular books about it, but biologists are not busy drawing up dozens of rival specific alien seeder theories in great mathematical detail; they're dealing with other areas of biology.

In theoretical physics, however, an idea that's been around three decades and still not produced any testables is still taking up a whole bunch of time, attention, and journal space. It looks like theoretical physics has degenerated into a cul-de-sac of fruitless theological debate. Why? There are other important theoretical questions in physics that can be explored while you lobby for equipment (experimental or observational) that could actually test string theory/quantum loop gravity/etc., so why are you physicists spending so much effort on the grand unified theories in the meantime?

Re:Physicist speaking

[m50d]

I was going to mention that, but that's much easier to deny - we've never actually observed Hawking evaporation, the only reason we think it exists is because it comes out of the current theories.

Re:Physicist speaking

[JohnFluxx]

> However, there is no serious effort spent by biologists working out the implications of this theory, because it is currently so untestable that it's a waste of time.

There are lots of papers on this actually, and there is even a rocket that will be launched next year carrying a mix of plants and bacteria to see whether they can survive outerspace. For example, we've already tested that waterbears (creatures about 1mm in size) can survive 10 days in a vacuum, and the new experiment will test for a much longer time.

We also have experiments to look for life on mars. If we find life on mars and it looks the same as life here, that could be taken as evidence that one of us seeded the other one.

> In theoretical physics, however, an idea that's been around three decades and still not produced any testables is still taking up a whole bunch of time, attention, and journal space.

And has produced new branches of mathematics and mathematical proofs. It's not as if the time is just wasted even if ST is wrong. We should understand the higher-dimensional math even if ST is not correct.

> so why are you physicists spending so much effort on the grand unified theories in the meantime?

Because with time, perhaps we /can/ find a way to test it? We're never going to find a way to test it if we don't even try.

Re:Physicist speaking

[JohnFluxx]

I always seem to write Loop Quantum Gravity as Quantum Loop Gravity. My brain and eyes seem to refuse to accept the original word ordering :-)

As for the rest - can you give me some actual evidence please? I don't personally know any scientists that would claim that string theory is the definitely the right theory, or claim that it's the only path, or want a LQG theorist to stop working on it.

Re:Physicist speaking

[JohnFluxx]

> What I said was that if they don't find the Higgs all hell will break loose

Ah right, sorry :-) Yeah

Re:Physicist speaking

[JohnFluxx]

Yeah, it would have struck the same nerve for me.

Re:Physicist speaking

[Anonymous Coward]

I'm surprised I missed that. But if you read the comics, there is really only one, and that is the series downfall, that it only tried to elucidate the motives of a single character as a "loner" apart from the group.

In some ways, the cartoons were better.

Re:Physicist speaking

[OrangeCatholic]

There is no Quantum Theory of Gravity. This is like saying we should be looking for a Pebble Theory of Gas Mileage. You are talking about things that are so far flung in size, they effectively do not influence each other.

The standard model is the way to go for now.

Re:Physicist speaking

[Anonymous Coward]

Brian Greene himself, in his book, describes it as "The only game in town". Weinberg says the same thing - quoted here

http://www.math.columbia.edu/~woit/wordpress/?p=1917

(I know Woit's blog reads non-partisan, but the quote is genuine).

Now, I think string theory is a great idea. It's really elegant, it has nice features, but personally I don't think it's right. I prefer background independence, and it's my belief (totally unsupported) that diff invariance is the main lesson of GR that we should take over to quantum mechanics. But, as someone working on other theories, I go to conferences and see brilliant ideas handwavingly dismissed because they're not strings.

If you listen to Smolin (again, not totally unbiased I admit) he tells of colleagues working on strings because they're the only way to get a job:
  http://www.scientificamerican.com/article.cfm?id=the-inelegant-universe

Or if you just talk to LQG researchers, like Rovelli, Ashtekar, Smolin, Friedel etc they'll all tell you about being told to give up on it and do strings.

Re:Physicist speaking

[John Hasler]

The Hawking vs God thread is two doors down.

String theorie isnt that bad at all.

[Anonymous Coward]

I think the one thing people forget, is that there is currently no theory that can describe everything.
So string theory isnt bad because it is one of the theories that it can not be proven by todays physic test, neither can other theories.
However most important point is that it is a framework of math.
And just to remind you all, it is math that is the front runner of physics.
For example Einstein was first to find blackholes based only on his math, and some years later they where indeed found.
And gravity waves we are still looking for it, because Einstein predicted them. (but perhaps we never find them, as we know to little about what is the carrier of gravity currently).

However, and this happened to other theories as well, if they can describe 'other' physics processes. Then it might be that the framework has potential, as it can describe more then the area it originated from. For a theory of everything that's on thing that it should be able to do.
However we still know to little about it all, so if this doesnt work out, it might be because we dont understand string theory enough (íts damn complex) or we dont understand the real world enough on it various scales (from photons to planets, and star clusters).
Realy finding a theory of everything could keep us busy for the next 2000 years that wouldnt surprice me at all. However most people think that the discovery of string theory was a huge step forward, almost a to big step. Therefore it surprises us it so many ways, we know a bit about the framework of this math, but we dont know how it is used by nature. And thats why we still have a long long long way to go.....

Just start thinking of something that results in time or in our dimensions... thats the thing string theory complexity, way beyond the 'simple' quantum mechanics, and way beyond our current imagination too..

Re:String theorie isnt that bad at all.

[Anonymous Coward]

For example Einstein was first to find blackholes based only on his math

Uhm, wouldn't that be Karl Schwarzschild?

Re:String theorie isnt that bad at all.

[Anonymous Coward]

Yep. And Einstein didn't learn about gravitational waves either, he thought that Minkowski space was the only vacuum solution until he was told otherwise by Friedmann.

which string theory?

[jamesh]

which string theory?

The one that will come out of the renormalization that they'll need to do to make it fit the observed outcome of this experiment, obviously.

Re:which string theory?

[Anonymous Coward]

I can't help but wonder: which string theory?

The theory about what will be done to you if you spray the President with silly string?

Re:which string theory?

[Anonymous Coward]

Regardless of what they find, is there a more useless theory they could be pursuing like Unified theory, or does most of what occurs in a physicist's day pretty much pointless. Its not like they could be working on more advanced nuclear reactors or better and cheaper insulators or alternative fuels. No, lets pursue castles in the sky. It'll sound impressive as a news story and we'll get a government grant for it! Yeah!

I think the complain about string theory

[Sycraft-fu]

Is that it isn't. What I mean by that is it doesn't seem to make any testable predictions. At this point, it is just a bunch of math wanking. Now there's nothing wrong with purse math. A lot of useful theories start out that way and I like the Bacon quote "If in other sciences we should arrive at certainty without doubt and truth without error, it behooves us to place the foundations of knowledge in mathematics."

However when all you've got is a bunch of neat math with no real testable predictions, it is not a theory and it is not the sort of thing to be crowing about to the general public. XKCD, as usual, did a humorous job summing it up: http://xkcd.com/171/.

If you are going to complain that people complain about the lack of testability then you need to do two things:

1) Read The Logic of Scientific Discovery again and brush up on what a theory is and isn't.

2) Don't go making press releases. I'm not saying you personally have done this but physicists are awful happy to talk to the press about something they can't prove.

Part of it is simply wanting accuracy in the use of the words because let's face it: In science accuracy matters. Being pedantic about terms is important in science. Another part of it is this is the kind of thing that confuses normal people. With evolution, scientists have gone to a lot of trouble to explain that a theory is NOT a guess, NOT a wild idea, etc. They show other theories and how they work, how many things we accept as true are theories.

Well something like this undermines that to an extent, because here is something being called a theory that is not only untested, but that they can't even figure out how to test. It is the kind of thing that can make people say "But wait, if this is a theory then theory doesn't mean what you said."

Re:I think the complain about string theory

[daniel_i_l]

Now there's nothing wrong with purse math.

That's a massive understatement. For most people, money counting is the most important type of math.

Re:I think the complain about string theory

[JohnFluxx]

Yes, the naming sucks. String Theory is not a theory, Newton's laws of motion are not laws, etc.

Re:I think the complain about string theory

[mqduck]

I like the Bacon quote "If in other sciences we should arrive at certainty without doubt and truth without error, it behooves us to place the foundations of knowledge in mathematics."

You're excited about the new Civilization too, huh?

Re:I think the complain about string theory

[ceoyoyo]

String theory makes a bunch of testable predictions.

What it doesn't do (yet) is make any easily testable novel predictions. They all require incredibly powerful accelerators, access to black holes, or similar extreme situations. Which is not particularly surprising, because where string theory differs from GR and QM is in the extreme environments in which the two existing theories break down. In ordinary environments string theory predicts (where you can do the math) the same things as QM or GR (as appropriate).

A lot of string theory research looks for clever ways of testing the theory without having to travel to a black hole or make an accelerator the size of the universe. Of course, this hypothetical clever experiment would likely also explicitly falsify GR and/or QM....

Alternately, since string theory tries to explain everything with a very few (ideally 1) input parameters, you could show it's superiority by, for example, deriving the masses of the known particles. Those masses, all of them, are input parameters to the standard model. There's a lot of interest in doing that as well.

Easy Peasy!

[Rouverius]

mTheory = isString("foo") Sorted! VBA Rules! ... Wha?

Then don't call it a theory, ya know?

[Moraelin]

Actually, it seems to me like we don't call those grand-unified things a proper scientific theory either. As long as there are no testable predictions, and it fails Occam's Razor, it's not a theory, plain and simple. It's a hypothesis.

Yes, there is a name for a theory which hasn't yet been tested: hypothesis.

And really, as someone who's gotten tired of hearing Young Earth Creationists go "well, evolution is just a theory" and having to explain to them "yeah, but theory in science doesn't mean what you think. It means it already made testable predictions and is the best we have"... it's getting annoying to see that a whole bunch of physicists are actually using it exactly as the YECs and conspiracy theorists think: as just an untested and untestable supposition, which may or may not actually hold any water at all.

Yes, I realize that calling it a "theory" is more science-y sounding and good for your funding. But it devalues the whole idea of science for everyone. If we accept that some untested and untestable calculation is just as worthy of being called a "theory" with a straight face as GR or electromagnetism just because it's the pet supposition of some physicist, then basically why wouldn't Behe's pencils-up-the-nose ID idiocies be a "theory" too? I mean Behe _is_ a professor of biochemistry.

Call it the String Hypothesis, and you'd see a lot less complaints, basically.

Re:Then don't call it a theory, ya know?

[Haxamanish]

Yes, there is a name for a theory which hasn't yet been tested: hypothesis.

A hypothesis is the starting point. A theory is the hypothesis and everything which follows from it. The hypothesis can be true or false, a theory can also be true or false.

Re:Then don't call it a theory, ya know?

[Anonymous Coward]

No account means no mod points for me.

Haxamanish is correct. In mathematics (which basically includes physics), any body of axioms and resulting theorems is a "theory", even if it doesn't have (known) real-world application.

E.g. "Ring Theory" is a theory not because it is correct, but because of how it was derived.

Re:Then don't call it a theory, ya know?

[maxwell demon]

In mathematics (which basically includes physics),

Your parenthetical remark is where you went wrong. There's a difference between the use of the word "theory" between mathematics and physics. A mathematical theory isn't a physical theory. A physical theory may qualify as mathematical theory as soon as you rip all the physics content from it, though.

Re:Then don't call it a theory, ya know?

[Haxamanish]

Thanks you for supporting my point of view - you should create an account, then I could become a fan :)
However, I disagree with mathematics including physics. I consider mathematics as being a tool or even a language used by physiscs.
Disclaimer: I'm neighter a mathematician nor a physicist (I'm a logician.)

Re:Then don't call it a theory, ya know?

[khallow]

Haxamanish is correct. In mathematics (which basically includes physics), any body of axioms and resulting theorems is a "theory", even if it doesn't have (known) real-world application.

It's a subtle point, but math itself is not science. One doesn't derive testable hypotheses of the physical world from pure math. It's only in applying math to physical phenomena, that it has scientific value. In particular, just because something is called a "theory" in the mathematical sense, doesn't mean that it is a theory in the scientific sense. "Ring theory" is a good example of this.

Having said all that, I do agree that Hexamanish is correct. It's just that we need to be a bit cautious when drawing parallels between how things are done in science and math.

Re:Then don't call it a theory, ya know?

[LateArthurDent]

As long as there are no testable predictions, and it fails Occam's Razor, it's not a theory, plain and simple.

I hate Contact, I hate Contact, I hate Contact.

Because Carl Sagan had a misunderstanding about what Occam's Razor is, but nevertheless explained it wrongly in Contact, now millions of people have been introduced to the concept as explained by his novel or the movie. "The simplest explanation is usually the correct one" is not Occam's Razor. Occam's Razor says nothing about correctness at all, and it's most certainly not a requirement to create a scientific theory. All it actually says is that if two theories make the exact same predictions, with absolutely no differences but one is more complex than the other, than there's no reason to use the more complex theory, even though it's perfectly reasonable that the more complex one could more correctly describe what actually happens. The point is, science is about making predictions and testing them, not about some other abstract form of "truth." If you can't differentiate them through this method, you have determined you can't be any more specific about "truth" but you have not determined that one is more likely than the other.

Re:Then don't call it a theory, ya know?

[Anonymous Coward]

(I'm the GP.)

The definition of "science" is somewhat debatable. (Though I also lean towards Popper somewhat.)

Mathematics is not testable in the real world because we cherry-pick the mathematical model based on our observations. If an observation doesn't match our mathematical models, we either pick a different model or call the observation an error.

It is however, still falsifiable as a logical system: by looking for inconsistencies (we cannot prove most of mathematics consistent). Thus, it is entirely falsifiable to a dualist or to a idealist, but not to a materialist (which I assume you are).

Yeah, philosophy of science is crazy stuff.

Re:Then don't call it a theory, ya know?

[Anonymous Coward]

Hmm. I've already replied to this... /. seems to be throwing away half of my posts. (As far as I can tell, anyway. It seems I have to jump through to loops get it to show replies on a post. Only works if I open the post in a new tab(?!))

Anyway, I admit that I had made a very bad choice of words. I should have said that physics is a mathematical system in the same way that mathematics is a logical system.

Re:Then don't call it a theory, ya know?

[Anonymous Coward]

Looks like /. discarded my reply. I'll post again.

I see what you mean, and I agree that my choice of words was bad.

What I should have said was this: String Theory, like Newtonian physics, General Relativity, etc. is a mathematical system. All theoretical physicists are, to a great extent, also mathematicians.

It therefore makes sense to me that the word "theory" be understood in the mathematical sense, which is the only one that makes sense for the name. Particularly if you also take into account that String Theory has only ever been tested mathematically, never through physical experiment.

Re:Then don't call it a theory, ya know?

[khallow]

It is however, still falsifiable as a logical system: by looking for inconsistencies (we cannot prove most of mathematics consistent). Thus, it is entirely falsifiable to a dualist or to a idealist, but not to a materialist (which I assume you are).

I guess that depends on the materialist. Even though I can't observe mathematical logic directly, I can observe certain doughnut and coffee swilling phenomena which seem to be to model flexibly the mathematical logic that we're interested in.

Moving on, my understanding is that science is by definition materialistic (even if I weren't materialist). Falsifiability is a rather broad criteria and there are many things that fall under it that I wouldn't consider scientific. For example, trying to make money on the stock market. A method for attempting to do so is crudely (though inconsistently) falsifiable in the sense that you can try the strategy out and see if you lose money doing it or not. It's not scientific (for example, it's not reproducible and almost nobody does the scientific process), but you still get a falsifiable test.

From a mathematical point of view, falsifiability is just a computation over some system, wholly dependent on the state of the system, that results in two or more possible outcomes with each outcome achieved by some states.

Re:Then don't call it a theory, ya know?

[Anonymous Coward]

For example, trying to make money on the stock market.

This *can* be a science, although in practice it's just gambling. (Such a science would be ever changing, since other speculators would soon take your models' predictions into account and the system would change.) Anything that can be observed can be studied in a scientific way.

Of course I agree that "scientific" is more a rule of thumb than a fixed definition. Personally, I just read some of the ideas of Popper, Kuhn, etc. and get a general feel for it.

But it is not by definition materialistic. A materialist probably told you that. :) (I don't think there will ever be an agreed upon definition. And when it gets to the soft sciences, things get even more muddy.)

Re:Then don't call it a theory, ya know?

[konohitowa]

And really, as someone who's gotten tired of hearing Young Earth Creationists go "well, evolution is just a theory" and having to explain to them "yeah, but theory in science doesn't mean what you think. It means it already made testable predictions and is the best we have".

Since every bastard on slashdot, minus one, seems to be nitpicking you, I thought I'd complete the cadre.

Evolution isn't a theory; it's an observation. Natural Selection is a theory that attempts to explain the observation. Agree? Disagree? Discuss amongst yourselves.

Arxiv version of the original paper

[ortholattice]

is here: http://arxiv.org/abs/1005.4915.

Nylon theory (nylon is made of strings, you see)

[fyngyrz]

No, it's nylons... and they only go down from the thigh (otherwise we're talking about pantyhose, which are a creation of the devil.) From the thigh up, it's garters. If you find turtles, retreat immediately. It's likely to get worse, and you don't want to know about that... guys that want to know about that become gynecologists. And no one with any sense at all wants to encounter dark matter. Also, garters first, panties (optional, of course), second.

Experimenting in this realm is highly recommended. Repeat a lot - you want to be sure.

String theory now testable

[Joce640k]

It's gonna be so cool if it says "wrong!"

If we're going to be pedantic...

[fyngyrz]

...then let's not throw around phrases like "theories accepted as truth."

A much better way to construct such a remark is "theories we presently have (very|extremely|) high confidence in."

Because I gotta tell ya, "truth" is one of those nasty words, like "belief", that usually - outside of logic and math, where it means something else - means someone is glossing over something, and it's probably not insignificant.

Just saying. You want a way to write about worldviews - including scientific ones - that doesn't trip you up, the best English-language concept I've ever run into is confidence. "Highly confident"; "Very little confidence"; it even allows for zero confidence and 100% confidence but it doesn't go around anointing ideas with either one by default the way the words "truth" and "believe" do. Allow for the possibility of change, and the acknowledgment of previous differences with "presently" (or whatever time frame is appropriate) and all of a sudden you sound like a reasonable person, because you're speaking reasonably.

It's much easier to speak accurately about everything from the big bang to Boyle's laws for gasses when you drop the truth thing and use confidence instead - it's *very* good for teaching, too.

Re:If we're going to be pedantic...

[Sycraft-fu]

I'm speaking of regular individuals. Yes I understand that when you get down to it, nothing outside math can be prove true as in no room for anything to dispute it ever (and of course just because something is true in math doesn't mean it applies in the world, could all just be in our heads). However normal people accept things as true, and they accept much of science as true. So truth is a useful thing to talk about.

Re:If we're going to be pedantic...

[OrangeCatholic]

Wow I hope this is a troll for your own sanity. Use ctrl+F on "truth" and see your epic fail.

god is a natural progression of ignorance

[Colin Smith]

ignorance and vanityfirst there were spirits everywhere, then as we learned to understand the world, these became pantheons of gods, then as we learned more, reduced to the one god. God is then just our ignorance of the world and the vanity of those who cannot answer 'i do not know'.

Re:god is a natural progression of ignorance

[jamesh]

God is then just our ignorance of the world and the vanity of those who cannot answer 'i do not know'.

You say that like it's a bad thing. Even if science explained every last little detail of the universe, there is no way that the majority of people are going to understand it without devoting their entire lives to doing so. As far as they are concerned scientists telling people that there is no God are just as bad as the crazy guys standing on the street corners telling people that Coke and Pepsi are the same thing.

A belief in God gives some people tremendous comfort in a world that otherwise doesn't give a shit. I don't believe in God but I don't seek to stop others believing. I draw the line at anyone who comes knocking on my door (or anyone elses door) telling me what to believe, or committing any sort of atrocity in the name of their deity, but otherwise I think a bit of personal faith can be good for people.

Re:god is a natural progression of ignorance

[mea37]

And ironically, atheism is also the vanity of those who cannot answer 'I do not know'.

Re:god is a natural progression of ignorance

[allusionist]

No. Even strong atheism merely claims "I don't know what the answer is, but I believe your explanation is incorrect."

As a gnostic atheist myself, I don't pretend to know what happened before the big bang - or even if there was a 'before', or if that question is even meaningful or sensical. I will claim that a god as usually described by the Abrahamic faiths is nonsensical, however, as are most other specific claims about deities or other supernatural entities/phenomena. There are a few exceptions, like the deistic idea of god, that cannot be disproven - but I do not believe in them either, for a number of reasons.

Re:god is a natural progression of ignorance

[mea37]

So you also deny the existance of people who claim to know there's no God? Well, on that one you are provably wrong.

Go on claiming to hold the One True Meaning of the label all you want, but I'm going to continue characterizing atheists' beliefs in terms of how self-described atheists characterize their own beliefs in actual conversation.

Re:god is a natural progression of ignorance

[allusionist]

Basic reading comprehension is a useful skill. You may want to consider learning it. Allow me to break this down a bit more for you, since I apparently assumed too much.

>As a gnostic atheist myself,
>So you also deny the existance of people who claim to know there's no God?

Brief English lesson. Gnosticism is the claim that it is possible to know the truth about the existence of God or gods. Agnosticism is the claim that that truth is unknowable. A gnostic theist believes there is a god and believes it is possible to know this to be true. An agnostic theist believes there is a god but does not believe that it is possible to know for sure. An agnostic atheist ("weak atheism", often incorrectly referred to simply as agnosticism) does not believe in god and believes it is not possible to know for sure. A gnostic atheist ("strong atheism") does not believe in god and believes it is possible to know this to be true.

I do not deny the existance of people who claim to know there is no god - gnostic atheists - in part because I AM one.

Now let's look at what I was replying to, and I will explain my response in greater detail.

>And ironically, atheism is also the vanity of those who cannot answer 'I do not know'.

Agnostic atheists are essentially making the claim "I do not believe it is possible to know if there is a god or not, but I do not believe there is." Clearly this comment does not apply to them, but I did not believe it was meant to, so I didn't bother spelling it out.

Gnostic atheists, strong atheists, whatever you want to call us, those seem to be the target of the original post's claim, as we are at least making some kind of positive claim - that it is possible to know whether there is a god. If you are agnostic (whether you are an agnostic theist or agnostic atheist), that may seem to be a vain claim. However, we are completely capable of answering "I do not know" and will do so when appropriate. My post provided examples - we don't claim to know what happened before the big bang or if the concept of 'before the big bang' is even valid. We claim we do know on the god issue specifically, but not on any of the multitude of related questions.

The reasons for making a gnostic claim vary from person to person - in my case, the argument is simple. Every claim of a deity that actually does something, has some kind of effect on the world beyond making it in the first place, can and has been disproven. We cannot disprove a god who does not influence the world any more than we can disprove there is an invisible, intangible pink unicorn who lives in my basement and leaves no trail of it's passing and doesn't touch or influence anything. However, I feel we can safely disregard these claims because they are meaningless and worthless. They add complexity without providing new information or allowing for predictions of anything. If you take a model of the universe based on only observable data and one that is identical except that there's also something we can't detect that doesn't affect anything, and both make exactly the same predictions, there is no reason to bother with that invisible entity in our model - Occam's razor applies here.

If you can give me an experimentally sound model of a god who has some kind of influence in the workings of the universe, that is detectable and allows us to make some kind of prediction about something not explained by the naturalistic model, I'd be willing to reconsider my stance. But based on all evidence currently available, I believe such a god does not exist.

the english language is broken

[Colin Smith]

it is missing a required pronoun.

Re:the english language is broken

[Krahar]

Unfold your wisdom on poor me and explain what you are talking about. What is insulting the English language is "Apologizing for referring to the Christians' god as a he". It is not "he" who insults the English language. What am I missing?

Re:the english language is broken

[Tim C]

No it is not.

Re:the english language is broken

[Anonymous Coward]

Well obviously the correct choice is s/he/it.

Of course it may not be correct, but I certainly like how it sounds.

Re:the english language is broken

[Colin Smith]

Yes it is. It introduces ambiguity and makes communication more difficult. In a language, that is broken behaviour.

Other languages have the required set.Or they have explicit cases where the ambiguity is removed. English has long since lost the cases.

Re:the english language is broken

[Colin Smith]

English is missing a third person singular - unknown/indeterminate gender personal pronoun. "he" is masculine, "she" is feminine, "it" is impersonal. "They" is plural.

There's something missing from the language.

It comes about from dropping cases over time. Or you could always use "sheit" instead.

Re:the english language is broken

[Krahar]

"he" covers both a reference to a male and a reference to someone of unknown gender. There is no case missing, it's just ambiguous. If someone feels they absolutely must follow the pointless radical feminist agenda on this, use "she" instead for the same purpose. Apologizing every time you need an indeterminate gender is language pollution - that is what I was saying.

Puppet on a string

[arth1]

If you want to complain about string theory not being testable, then accept that your same complaint is going to apply to EVERY grand-unified-theory that we know of.

And why do you think this would be a problem? My complaint about the Christian god not being testable does also apply to other deities, but the Christians are the ones pissing in my back yard, so those are the ones I complain about. Similar with the string faith.

If you complain at string theory, then PLEASE state what you are proposing.

That's a fallacy. Complaints are just as valid without the complainer presenting alternatives.

What is the use in complaining when you have no alternative?

What's the use in complaining about the Christian faith when you have no alternative? In my opinion, having no alternative is not a bad thing in itself. There are many things we do not know yet, but the answer isn't to come up with an explanation that can't be disproved and gather followers. IMO, string theory is worth putting in a drawer with a note saying "do not open until testable", lest it cause confirmation bias due to lack of falsifiability.

People complain at string without proposing anything better.

People complain about a LOT of things without proposing anything better, and often rightly so. It's the job of the scientist to look for something better, not reinforce her own beliefs.

Rediculous.

[AntEater]

This has been solved for quite a long time. Perl's built in regular expression tests have had the ability to check for strings for many years now.

if( $var =~ /\w/) {}

Still hasn't got his Penny

[syousef]

That's a good news for Dr. Leonard Leakey Hofstadter...

But Penny will forever be a bitch and a traitor for letting Will Wheaton spook her into dumping him!

Re:Still hasn't got his Penny

[jollyreaper]

But Penny will forever be a bitch and a traitor for letting Will Wheaton spook her into dumping him!

Don't blame her, blame the writers. But she'll be back. He's ruined her for dumber men.

Falsiability is old

[Anonymous Coward]

Science is not about disproving stuff. All theories (unless you made them really wrong) account for some measurements. All you can do to theories is measure their range of applicability. You cannot say it's entirely false out of one measurement. You can only say that measurement is out of its range of applicability.

Plus, theory background stories (like 'all is made of strings') are not 'reality'. Even if they are the reality, you cannot be sure of that.
All that matters to science are ways to relate measurements. That's it. The rest is sensationalism.

Maybe the numbering system is the problem...

[courteaudotbiz]

While we are trying to use maths to solve pretty much everything, maybe the thing that is flawed is our numbering system?!?

Remember the roman numbers? It was supposed to be the most logical thing in the world back then. Then we came up with base 10 / positional numbering system. All of a sudden, everything was simpler, everything was easier to calculate, and it opened up our eyes on a lot of things.

But then, maybe we reached the end of what our numbering system / way of thinking about maths, can do.

Just asking. I'm not that good at maths, I'm not a physician nor a chemist. But looking at history, we may be all the way wrong again.

Re:Maybe the numbering system is the problem...

[marcosdumay]

Your poster tells that you aren't good on math or physics. Just as an example, QM doesn't rely on 'our nunbering system', almost all calculations are made on a Hilbert space, based on the Dirac delta function. There are no numbers as you know them there. Ok, sometimes a real nunber pops from a calculation, but that is normaly just after all the heavy stuff.

Every physics theory uses a different 'numbering system'.

Re:Maybe the numbering system is the problem...

[Arthur Grumbine]

While we are trying to use maths to solve pretty much everything, maybe the thing that is flawed is our numbering system?!?

Hear, hear!

From now on I propose the following for the new numbering system:

1. Thou shall count to three, no more, no less. Three shall be the number thou shalt count, and the number of the counting shall be three.

2. Four shalt thou not count, neither count thou two, excepting that thou then proceed to three. Five is right out.

3. The largest number is 45,000,000,000.

Re:Maybe the numbering system is the problem...

[Anonymous Coward]

Binary is certainly more logical than base 10. The ten in base 10 is completely arbitrary and based on how many fingers we have. On the other hand, binary is the Occam's Razor of bases: any less and you've lost all the advantages of the base N system as opposed to the Roman numeral system, while any more introduces needless complexity in theoretical math without making it more powerful. Too bad it's usually only the computer science-related mathematicians who use it.

Re:Maybe the numbering system is the problem...

[hedwards]

Actually it's pretty solid, the only thing in the last 200 years or so that it's really screwed it up was when somebody disproved the fifth postulate. Which is to say that it wasn't the numbers that were the problem it was the presumptions we were making about reality which were. And right after the work to disprove it was completed all kinds of really amazing discoveries were made. There's still a lot of things like that out there to do, the biggest one is that there's a tendency to assume that because it works on paper that it works in real life, which is patently false. That's the only reason why we waste money on experiments is because sometimes the thought experiment or the calculation turns out to be wrong, in which case weird things happen.

Some areas are worse than others, probability theorists seem to be particularly blind to the absence of any means of accounting for entropy and outside factors affecting what they're looking at. And I know from personal experience that you can do all sorts of really weird and amazing things by taking even a rudimentary stab at including those other factors in.

Re:Maybe the numbering system is the problem...

[KnownIssues]

The thing is, decimal didn't make everything simpler and easier to calculate and open up our eyes. It feels that way, because you've spent you're whole life using it and everything else feels weird and foreign. Base 10 feels natural because we have 10 fingers and 10 toes (among other reasons).

But you can see the evidence of our history of using base 12 from our words for numbers (this is the reason eleven and twelve aren't firsteen and seconteen). Base 12 is also very natural because it has so many factors (1, 2, 3, 4, 6, 12), making it easy to do calculations in our head. This is also why much of our U.S. measuring system is base 12 (12 inches in a foot, and other conversions using factors of 12). You can also see evidence of base 60 (60 seconds in a minute, 60 minutes in an hour). Computers use base 2, because for computers, binary math more natural than decimal math.

My point is say that our numbering system is a constructed convenience and (as far as I know) no forms of math depend on the decimal numbering system. It is merely a convenience (and I think one could probably argue, the least convenient convenience) to have everyone agree to use a single base for calculations.

And to close with a nitpick, according to Wikipedia at least, Roman numerals are decimal. The numerals for 5 are a shorthand, but don't represent the base unit.

Re:Maybe the numbering system is the problem...

[Nemyst]

That's like saying that your understanding of psychology is flawed because you speak English. The numbering system has absolutely nothing to do with what we're dealing with here. You could count in base 8, 24 or in bananas and it wouldn't change a thing. Roman numerals are just a different way of writing a base 10 numbering system. They don't have any bearing in the results, only in the ease of writing numbers.

And finally, being a physician or a chemist wouldn't help much... Maybe you meant mathematician and physicist? :)

Re:Maybe the numbering system is the problem...

[Rand Race]

I believe he's talking about positional notation rather than base. Roman numerals could be considered Base10 but they can not be considered positional. They use sign-value notation instead.

I don't see the point however. As mentioned above, physicists derive their own math all the time.

Are you sure about 11 and 12? The French continue using discreet words for numbers up to 16, but I wouldn't go so far as to say they developed that from some hexadecimal system of the past. Especially since Italian goes strait to "Ten and One" (undici) without discreet words for 11 or 12 much less 13-16. Spanish has 1-15 discreet but not 16. 1-12 being discreet seems to be a purely Germanic thing; English, German, Dutch, Danish, Swedish and Norwegian all do it, but neither the Slavic languages nor the Romance languages that border the Germanic group do so. In fact, the only non-germanic language that uses words like "eleven" and "twelve" (which mean "one left (over ten)" and "two left (over ten)") is Lithuanian and it uses them all the way to 19 (devyni-olika "nine left (over ten)").

Re:Maybe the numbering system is the problem...

[KnownIssues]

You are right. I was wrong. I spoke in ignorence. According to the Wiki article on Duodecimal:

Germanic languages have special words for 11 and 12, such as eleven and twelve in English, which are often misinterpreted as vestiges of a duodecimal system. However, they are considered to come from Proto-Germanic *ainlif and *twalif (respectively one left and two left), both of which were decimal.

I also concede your point that he was referring to positional notation and the concept of zero.

Re:Maybe the numbering system is the problem...

[Dr. Gamera]

At first, I was going to mod your comment down for being hopelessly naive, but then considered that, on the contrary, it might be really deep, so I'm replying instead. You might be looking for something like operator theory, which has been in wide use only for the last century or so. Unfortunately, I can't point you to a good introduction to the topic -- cursory web searches were unhelpful -- but perhaps someone else can.

Re:Maybe the numbering system is the problem...

[Agent0013]

Actually the most efficient base to use is base e. Something about the number of symbols needed multiplied be the length of the resulting numbers, and base e comes out to be the most efficient. I don't know how you can use a base that is not an integer, but those really awesome math people can do it.

Re:Maybe the numbering system is the problem...

[david_thornley]

You're confusing numbers and their representation.

Numbers exist or not (depending on your point of view) independently of their representation. Given two representations, we can express a single number in either. Since we aren't good at thinking about numbers without representations, we can just freely convert between representations. For example, DII and 502 represent the same number.

If somebody extended Roman numerals to include fractions, zero, and arbitrarily large numbers, it would represent the exact same numbers as our current scheme did. The only difference is how easy it is to do the arithmetic.

When getting deeper into mathematics, you usually aren't using specific numbers. Even in algebra, you start using letters to represent numbers, just not in the Roman way. You can do a whole lot of reasoning about numbers without using many specific ones (typically you will use 0 and 1). At that point, it doesn't matter what representation system you're using.

Also, we've already moved away from the decimal system in many applications, using binary instead. That, again, is for convenience of computation and nothing else.

Re:Maybe the numbering system is the problem...

[Bryan K. Feir]

I suspect it's similar to the concept of fractional dimensions used in fractals. With a Sierpinski cube/Menger sponge, for example, if you triple its size in all three dimensions, you end up with 20 times the volume, rather than 27 times for a solid cube, or 9 times for a square. So it has an effective dimension of log 20/log 3, which is an irrational value between 2 and 3.

Second most complaint?

[Burnhard]

The second most complaint I have with String Theory is how ordinary people can possibly understand the mathematics. I can just about grasp Einstein, Tensors and so forth. Multidimensional manifold's, M-theory and the like leave me feeling intellectually inadequate. Is it all just some obscurantist joke, or is reality really that complicated?

Re:Second most complaint?

[marcosdumay]

Well, I'm just a layman too, but I rely on the word of some math specialists, that confirmed that it indeed is that hard. Anyway, there is no requirement on the scientific method that your theory must be understandable by lay people, or even by specialists of the area, it must be as complex as the data requires.

Re:Second most complaint?

[m.ducharme]

Argument from your own inadequacy isn't really argument.

Re:Second most complaint?

[Burnhard]

I think what I'm getting at is that the mathematical shorthand we use to describe (model) the regularities of our experience is becoming increasingly complex and decreasingly represents anything we can even actually visualise. I think the divergence between our perception and the objective realities we uncover through experimentation is instructive in this respect. That is to say, knowing how the brain constructs subjective reality (Conscious Experience) is required before the essence of objective reality can be fully understood. Until then, the theories will become ever more complex, obscure and less likely to ever actually be able to describe anything real.

Did that make sense? Hmmmmmmm.

Re:Second most complaint?

[Burnhard]

Argument from your own inadequacy isn't really argument.

Indeed, that nobody really understands these things is self-evident and is, it seems to me, the very foundation of the argument. Most physicists I've encountered don't concern themselves with understanding; they concern themselves simply with adequately describing. Hawking is misguided in this regard, I believe. After all, it doesn't matter how general or all-encapsulating any given equation is, there will always be something left to explain.

Re:Second most complaint?

[marcosdumay]

Didn't make a lot of sense to me. That the theories actualy describe something real is a given from the fact that we check them with reality, by experimentation, and dicard what doesn't fit. Also, there shouldn't be any relation between our understandind of our conscience and how complex theories are. At least, I see no reason why that would happen.

I may agree that "knowing how the brain constructs subjective reality (Conscious Experience) is required before the essence of objective reality can be fully understood" (that means, I'm not sure I agree, but I don't imediately disagree), and that is a very interesting comment. But I fail to see any reason why understanding objective reality would lead to different kinds of physical theories. Physics seems to be completely independent of realism (at least without other independent assumptions).

Oops; that was a misquote (correction)

[mcgrew]

"With all due respect, Dr. Cooper... are you on crack?" -- Dr. George F. Smoot III

Where is...

[Anonymous Coward]

the pizza analogy guy on this one?

So, what we've got here by analogy

[Guil Rarey]

Is a bunch of people trying to hack on physics to bridge GR and QM. There are a couple different ways to do this. Strings are one, loop quantum gravity is another.

Right now, everyone is still in pre-release debugging, not even beta-testing. It's ALL VAPORWARE. Complicating things, as always is money - grants, funding, publication, as well as ego and rep - appointments, tenure, etc. The truth will out eventually - the theories WILL mature and develop; testable, falsifiable hypotheses will be formulated - patience, grasshopper.

What I'd like to know, now, is who's the "Home Brew Computing Club" of this mess and who is the "Bill Gates writing bitchy whiny letters complaining about shit"?

Witten and Greene I've heard of. String theory and string theoreticians are carrying the day (in political / "marketing" terms) in the academy. Who is losing and bitching? Apart from their economic incentive to bitch, should they be?

Useful vs. Right

[bill_mcgonigle]

I guess I'm currently in the 'so what' camp. If a String Theory covers all of QM, Relativity, and Gravity, and it makes useful predictions that can be tested and leads to further knowledge and useful engineering - I guess I don't really care if the underlying assumptions are right or not.

By all means, keep working on something better, but if the above is true, it's a good theory to work with. We got quite a bit of useful work done with Newtonian physics, and QM/QED have gotten us much further, even if they're not quite 'right'.

If a String Theory is correct, then it will lead to insights we currently don't understand. If it's wrong it'll disagree with observation. I guess the fear is that it'll be wrong and agree with observation, which is the point where I diverge from those who worry too much.

Uhh... First?

[nitehawk214]

Err, in the suggested articles on TFA there is this link Theoretical Physicists Develop Test For String Theory From Jan. 25, 2007.

Did they just call bullshit on themselves?

You and Me Both, Buddy

[eldavojohn]

It seems I may have jumped the gun on this one. My bad for being such an easy mark of sensationalist pop science headlines.

Don't feel bad, I submitted it a day before you did. What really blows my mind is that Not Even Wrong used my submission as evidence that Slashdot was running a story on it:

Update: No press campaign for a “finally string theory is testable” claim is complete without a Slashdot story

Big news for theoretical physicists who are fed up with the inability to test String Theory

(that's from my submission)

Wazza?

[ErikZ]

In other words, string theory may finally have shed its critics' most common complaint: unfalsifiability.

It's critics? It's CRITICS.

Holy crap man. After spending a significant chunk of your life working on string theory, wouldn't you want to test it? That's part of the whole "I'm a scientist"!

Re:Wazza?

[tool462]

That's part of the whole "I'm a scientist"!

You'd think so, but I'm in it for the chicks.

Re:Wazza?

[david_thornley]

When I asked about getting into science for the chicks, they suggested biology, more particularly ornithology. So far, I see a whole lot of eggs being laid, and that's all that gets laid.

Re:Wazza?

[ceoyoyo]

My head hurts. You took the correct phrase in the summary "its (plural) crtics' (plural possessive)" and turned it into the mind bending "it's (contraction - it is) critics (plural)". Twice. With bold face.

Numb3rs

[Anonymous Coward]

Numbers have very little to do with the maths we're talking about at this level :-)

Then, stop you PR department

[marcosdumay]

String theory poses to the general public as what modern physics is. Take a look at the books available at a bookstore, science articles at the gernal press, etc. All you'll see is bold predictions about how our universe fist within a multiverse, how string theory explains the inner workings of a black hole, and so on. There is nothing wrong with you working on string theory, your PR department just needs to stop presenting it as a certainty.

Chill out, Pinky

[Moraelin]

Chill out, Pinky.

Where did I say I was using the one from Contact or anything. Yes, I'm using largely the version you explain there: as long as two hypotheses explain the exact same sets of measured data, go with the less complex one, leave the more complex one for when you actually have some data that the other one can't explain.

In exactly that sense, as long as the String Hypothesis doesn't have at least one testable prediction [b]of its own[/b], that can't be explained by the simpler GR and QM, it freaking fails Occam's Razor.

It doesn't mean it's _false_ and nowhere did I say it's _false_. I said until such time as it makes testable predictions of its own, it's just a _hypothesis_. Different thing from "false".

So basically, what, you made all that fuss to answer to your own strawman?

Re:Chill out, Pinky

[LateArthurDent]

So basically, what, you made all that fuss to answer to your own strawman?

You said a theory is not a scientific theory if it fails Occam's Razor, which is a completely incorrect statement. I answered you because you can't invoke Occam's Razor unless you have two theories that give identical predictions. That's clearly not the case for string theory considering that the reason for it is precisely because competing theories are lacking in the area of quantum gravity.

String Theory makes plenty of predictions, even if you can't go out and test them all right now. You don't have to be able to test your predictions with current technology in order to qualify as a theory. You simply need to have a complete framework from which predictions can be made. The many string theories might be too broad to be considered falsifiable based on what we now know, but data we get from experimentation will continually eliminate some of those string theory subsets, and help refine others. That's one of the reasons why string theorists get so excited about the LHC.

Re:Chill out, Pinky

[Anonymous Coward]

There are 10^500 - 10^1500 different vaccua. If you could perform one experiment per atom in the currently observable universe you would do 10^80 experiments. Let's say each nails down one parameter (and that's really optimistic). You would still have at least 10^499 models that fit the data. All of which predict different things for the next experiment you do. You cannot, within the lifetime of the universe, nail down all the parameters needed to make a predictive string theory. So, yes, you get excited about the LHC all you want, you'll still have zero predictive power and will never prove your theory right that way.

Yes:And when it fails this test too

[OldHawk777]

Love can kill you while you sleep; Therefore, you're born alone, you live alone, you die alone, or you get fycked and live for a few years, which is far better than being a living-dead alone not knowing when you died.

So, die in bed with a rock-hard... passion on for sex, R&B, R&R, SD&R&R, S&T, T&A... whatever brings your monster to life, to include the nice ugly babe that can screw you till your laughing-blue and die with a smile on your face!

Ptolemaic Planetary model

[jgtg32a]

I'm not at all qualified to say yea or ney on String Theory however it does seem to remind me of the Ptolemaic Model, they just keep adding constraints to try to shoe horn it in. Just because it works doesn't mean it's right

http://www.youtube.com/watch?v=wGjlT3XHb9A

Irony

[mcgrew]

Your comment:
Part of it is simply wanting accuracy in the use of the words because let's face it: In science accuracy matters. Being pedantic about terms is important in science.

Your sig:
All my foes are spelling or grammar Nazis.

Re:Irony

[dissy]

To be fair that would only be ironic if Slashdot was some form of scientific forum or journal.

These days, Slashdot is barely a message forum, what with the new metamod system weighing as much as normal mods yet not even displaying quotations properly, leading metamoderators to think you are stating what in fact you are quoting.

At least scientific journals don't hide your argument that you are presenting, and instead falsely claim you are making the very statements you are arguing against.

Re:Irony

[mcgrew]

Sadly, you're right.

As to metamoderation, I really REALLY wish they'd make that how it used to be.

A test to see if the Emperor has no clothes!

[mschaffer]

Finally, a test to see if the Emperor has no clothes!

(Well, at least some of the infinite number of possible emperors, anyway.) Hopefully, string theory can be brought into the fold of the scientific method.

String theory:

[Nyder]

Strings will get tangled and knotted, no matter how hard you try to keep them seperated.
Strings will break when there is no easy way to replace it.
Strings causes cats to stop what they are doing, just to try to grab it.

What other string theories am I missing?

Luckily

[jopet]

the thousand incarnations of "sting theory" have enough free parameters to fit any kind of reality. And to explain none.