[Geezer]

Lets take for granted the argument for instance, lets say somehow we know multiverse is the reality in which we live, there are an infinite number of universes out there, now, is it plausible to discover that by scientific means?

If you mean obtain empirical proof, I've no idea how we could do that, and that does seem to be a general issue with ST, but never say never I suppose.

Maybe I mean to ask, how does the math imply multiverse? And just how reasonable is it for us to conclude other universes exist simply because of this?

I don't think we really can conclude this without some empirical evidence, but, as I said, I'm no expert  []

[abacus9900]

Maybe I mean to ask, how does the math imply multiverse? And just how reasonable is it for us to conclude other universes exist simply because of this?

Because strings are thought to 'vibrate' in multiple dimensions and it seems there could be whole chunks of vibrating strings that exist as other universes (called membranes) with their own laws, depending on how strings vibrate in their membrane. What we observe as light, gravity and mass is hypothesized to be a manifestation of the way strings in our 4 dimensional world vibrate.


The point is that the mathematical model of strings is in accordance with the known laws and observations of science and appears to provide solutions to questions that have previously eluded science, so it is a 'good fit' based on our knowledge to date, although not testable.

[Farsight]

Melody: String theory aka M-theory has been going for 40 years now. There's no evidence for any of it, and it predicts nothing. Thus it isn't actually science, it's hypothesis at best, or pseudoscience at worst. Since it explains nothing and nobody can explain it, I err towards the latter. IMHO it has more than a whiff of "emperor's new clothes" to it.

Some will be unhappy to hear me say this, but they cannot explain it, and they cannot provide any evidence or predictions. After 40 years it just won't do. We can understand everything another way. And it is coming.   

[abacus9900]

Melody: String theory aka M-theory has been going for 40 years now. There's no evidence for any of it, and it predicts nothing. Thus it isn't actually science, it's hypothesis at best, or pseudoscience at worst. Since it explains nothing and nobody can explain it, I err towards the latter. IMHO it has more than a whiff of "emperor's new clothes" to it.

Some will be unhappy to hear me say this, but they cannot explain it, and they cannot provide any evidence or predictions. After 40 years it just won't do. We can understand everything another way. And it is coming.   

The latest version of string theory was proposed in the mid 90's so it is not 40 years old. It is the best 'fit' we have so far in attempting to provide a common foundation to account for all the known forces and particles and it agrees with all of the scientific observations that have been made about the universe. It is not testable it is true, but the mathematics of M-theory have been found to be very consistent in attempting to combine quantum mechanics with gravity. I don't see what more one can ask of a scientific theory that is attempting to answer the deepest mysteries of the universe. You have to start somewhere and, perhaps, one day science may be in a better position to test M-theory or perhaps its successors. Do you simply want no effort made in trying to provide a model (even a hypothetical model) of the basis of reality?   

[Geezer]

Since it explains nothing and nobody can explain it, I err towards the latter. IMHO it has more than a whiff of "emperor's new clothes" to it.
  

Didn't Einstein receive a similar reaction?

[abacus9900]

Didn't Einstein receive a similar reaction?

Exactly. Were the Greeks wrong to conceive of the 'átomos?' The idea certainly wasn't testable!

[JP]

I'm confused by what this debate is actually about. 

Is the question whether or not string theory makes testable predictions?  I don't think anyone's arguing that it currently does. 

Is the question whether or not string theory should be considered science?  That depends on how strictly you define scientific theories to require immediately testable results.  Many accepted scientific theories require a lot of effort before they make testable predictions.  Would Einstein have been working for years in philosophy, rather than science, because his general theory of relativity took a long time to complete?  If so, is there some immediate transformation from philosophy to science when the first testable prediction is made?  Does the attempt to work towards mathematically towards a testable theory count as science?  I think that you could argue this all day and not come to an answer.  The goal of string theory seems to be to eventually yield testable results and to make sure it agrees with current observations, so I would say that yes, it is a scientific field of research.  I'd probably stop short of labeling it a scientific theory, however--maybe it's a theory-in-progress.

Or is the question whether or not string theory should be attracting funding or scientific talent, since it may or may not yield practical results?  I suspect the mathematics behind the theory will turn out to be useful in other areas, even if the theory is eventually discarded, so that funding it is probably worthwhile.

[melodysquare (OP)]

Since it explains nothing and nobody can explain it, I err towards the latter. IMHO it has more than a whiff of "emperor's new clothes" to it.
  

Didn't Einstein receive a similar reaction?

And more people that were wrong on issues probably received the same reaction as well. Reactions don't tell us anything really at all.

Because strings are thought to 'vibrate' in multiple dimensions and it seems there could be whole chunks of vibrating strings that exist as other universes (called membranes) with their own laws, depending on how strings vibrate in their membrane. What we observe as light, gravity and mass is hypothesized to be a manifestation of the way strings in our 4 dimensional world vibrate.

It bothers me on a philosophical side that - what is everything is hypothesized to be the vibration of something, even if its not a "thing" in any sense we can imagine. For the mere fact that this thing must be doing another thing (vibrating) means it takes on a property of a sort, one that is allowed and defined by what? Does it not also require what it proposes to explain? Which is to say laws? Theres an infinite regress that I think scientist will someday have to accept or be driven mad by. Anyway, thats irrelevant - kind of.

So after reading this would it be correct to state multi-dimensional implies mutli-verse sort to speak? When we get down to the smallest principle of where those dimensions cluster/meet? 

Is the question whether or not string theory makes testable predictions?  I don't think anyone's arguing that it currently does. 

Well, take for example Stephen Hawking, here we have the smartest guy in the world stating a God need not start the Universe, stated almost as if a matter of fact, here we are in a science forum, and people seem to agree this theory that his premise is based on doesn't even have any empirical proof nor even sets any testable predictions. Theres a huge disconnect between the science community and the general public, now I fear theres a huge disconnect in what scientist think they're doing and what science actually is.

[Geezer]

It might be best if you try to break down your points into separate topic questions.

I think the original question was basically "Is String Theory science?" Although it is not an accepted theory, I don't think anyone has suggested it is anything other than science.

[abacus9900]

It bothers me on a philosophical side that - what is everything is hypothesized to be the vibration of something, even if its not a "thing" in any sense we can imagine. For the mere fact that this thing must be doing another thing (vibrating) means it takes on a property of a sort, one that is allowed and defined by what? Does it not also require what it proposes to explain? Which is to say laws? Theres an infinite regress that I think scientist will someday have to accept or be driven mad by. Anyway, thats irrelevant - kind of.

So after reading this would it be correct to state multi-dimensional implies mutli-verse sort to speak? When we get down to the smallest principle of where those dimensions cluster/meet? 

Using natural language to try to explain what M-theory is about is not always helpful because the models string theory are based on are largely mathematical. The trouble is, it is only natural to interpret the ideas in string theory in terms of the familiar everyday world we all know, but this is misleading because nature is often non-intuitive and even bizarre so we must not get too carried away by using familiar analogies in order to get a handle on difficult concepts. Words can get in the way in attempting to produce a model of phenomena like this, which is why people use maths. For example, who could possibly imagine what a fifth dimension is like? We have simply not evolved to deal with such ideas in any direct way.

[Farsight]

Didn't Einstein receive a similar reaction?

There were people who were sceptical, but GR received initial experimental confirmation after only 3 years in 1919. See http://arxiv.org/abs/gr-qc/0510072 for details of other experimentation.   

The latest version of string theory was proposed in the mid 90's so it is not 40 years old. It is the best 'fit' we have so far in attempting to provide a common foundation to account for all the known forces and particles and it agrees with all of the scientific observations that have been made about the universe.

I'm afraid that's a myth. Relativity is an excellent fit for gravity, QED is an excellent fit for photons and electrons, and QCD and gauge-theory in the form of the standard model is a reasonable fit for protons and other particles. M-theory "fits anything", and with the lack of predictions and supporting evidence, it isn't actually a theory.   

It is not testable it is true, but the mathematics of M-theory have been found to be very consistent in attempting to combine quantum mechanics with gravity.

That's another myth I'm afraid. Again, if you beg to differ, explain how it does this. When you find you can't, perhaps you'll appreciate what I'm driving at with the emperor's new clothes allegation.

I don't see what more one can ask of a scientific theory that is attempting to answer the deepest mysteries of the universe.

If it was a new theory, I'd cut it some slack. But it isn't, and it's been crowding out real physics. I'm not joking about this. 

You have to start somewhere and, perhaps, one day science may be in a better position to test M-theory or perhaps its successors. Do you simply want no effort made in trying to provide a model (even a hypothetical model) of the basis of reality?

Not at all. But there are models out there that do this, but you never get to hear about them because "string theory is the only game in town".

Using natural language to try to explain what M-theory is about is not always helpful because the models string theory are based on are largely mathematical.

If you can't explain it and if nobody can, we're in crystal spheres territory.

The trouble is, it is only natural to interpret the ideas in string theory in terms of the familiar everyday world we all know, but this is misleading because nature is often non-intuitive and even bizarre so we must not get too carried away by using familiar analogies in order to get a handle on difficult concepts. Words can get in the way in attempting to produce a model of phenomena like this, which is why people use maths. For example, who could possibly imagine what a fifth dimension is like? We have simply not evolved to deal with such ideas in any direct way.

This just won't wash, not any more. The future of physics is at stake. We can understanded such ideas in a direct way. Would you like a demonstration? Think of some subject that is usually considered to be mysterious and beyond current scientific understanding, and I'll explain it in a simple fashion that everybody can understand.

[Farsight]

...There's a huge disconnect between the science community and the general public, now I fear theres a huge disconnect in what scientist think they're doing and what science actually is.

It isn't like that melody. The disconnect is in the peer-review system and science communication through the media. There's a lot of good physicists out there writing excellent papers that don't get into Nature and that you don't get to hear about. Instead what you do get to hear about is M-theory, the anthropic principle, the multiverse and other such tosh. 

[abacus9900]

I'm afraid that's a myth. Relativity is an excellent fit for gravity, QED is an excellent fit for photons and electrons, and QCD and gauge-theory in the form of the standard model is a reasonable fit for protons and other particles. M-theory "fits anything", and with the lack of predictions and supporting evidence, it isn't actually a theory.

Perhaps you would like to provide some kind of evidence for this view.   

That's another myth I'm afraid. Again, if you beg to differ, explain how it does this. When you find you can't, perhaps you'll appreciate what I'm driving at with the emperor's new clothes allegation.

I have already explained this. M-theory is in accordance with all the scientific observations so far made and it provides a 'best fit' in uniting gravity with quantum mechanics - hypothetically yes, but, nevertheless it is the best theoretical model so far produced.  

If it was a new theory, I'd cut it some slack. But it isn't, and it's been crowding out real physics. I'm not joking about this.

'Real' physics has not provided answers to what underlies quantum mechanics and classical physics, especially gravity, so you are in error.

Not at all. But there are models out there that do this, but you never get to hear about them because "string theory is the only game in town".

You never get to hear about them because they are no good.

If you can't explain it and if nobody can, we're in crystal spheres territory.

How does one explain the fifth dimension? The mathematics need to be understood and not many people can understand!

This just won't wash, not any more. The future of physics is at stake. We can understand such ideas in a direct way. Would you like a demonstration? Think of some subject that is usually considered to be mysterious and beyond current scientific understanding, and I'll explain it in a simple fashion that everybody can understand.

Ok, explain what the fifth dimension is.

[abacus9900]

There's a huge disconnect between the science community and the general public, now I fear therIt isn't like that melody. The disconnect is in the peer-review system and science communication through the media. There's a lot of good physicists out there writing excellent papers that don't get into Nature and that you don't get to hear about. Instead what you do get to hear about is M-theory, the anthropic principle, the multiverse and other such tosh. 

Evidence please.

[Farsight]

Perhaps you would like to provide some kind of evidence for this view.

Have a read of this Scientific American blog, which actually mentions the word crap:

http://www.scientificamerican.com/blog/post.cfm?id=cosmic-clowning-stephen-hawkings-ne-2010-09-13   

I have already explained this. M-theory is in accordance with all the scientific observations so far made and it provides a 'best fit' in uniting gravity with quantum mechanics - hypothetically yes, but, nevertheless it is the best theoretical model so far produced.

You've explained absolutely nothing, you've given no evidence and no predictions, you've merely repeated unsupported assertions.  

'Real' physics has not provided answers to what underlies quantum mechanics and classical physics, especially gravity, so you are in error.

Yes it has...

You never get to hear about them because they are no good.

...but catch 22 applies. Because string theory is the trouble with physics. 

How does one explain the fifth dimension? The mathematics need to be understood and not many people can understand!

What fifth dimension? There isn't one.

Ok, explain what the fifth dimension is.

No, because there is no fifth dimension. See http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics for some real physics issues.

[imatfaal]

Farsight - I agree with most of what you are saying; but that is a crap article from SciAm. 

The finest sentiment I know of in this area is from Robert Laughlin in A Different Universe

'Far from a wonderful technological hope for a greater tomorrow, string theory is the tragic consequence of an obsolete belief system'

  There's also Not Even Wrong by Lee Smolin - another good read. 

The physics and the maths is beyond many, and certainly beyond me; but from a position of ignorance it does seem that the time has arrived for string-theory of some-guise "to put up or to shut up".

[Farsight]

I'll check that out imatfaal, and I totally agree with your sentiment. Note though that Lee Smolin wrote The Trouble With Physics, and it was Peter Woit who wrote Not Even Wrong, see http://www.math.columbia.edu/~woit/wordpress/.

[imatfaal]

You are right.  I am conflating two good books. 

Seeing your interest in the method of progress of science, can I ask if you have read much on the history/philosophy of science?  String theory strikes me as having strange parallels with the old notion of dogmatic paradigm; the devotees are brilliant but intransigent, and forever tweaking a dying theory rather than accepting possibility of other ideas.  If string theory does turn out to be all it is made out to be then it will have had the longest and most painful scientific adolescence; but I worry that in fact it has already passed to the stage of stubborn and inflexible senescence.   However, I do prefer our world where a group of unbelievably intelligent theorists can chase a pipe-dream for decades rather than one where tenuous and potentially futile avenues of research are stopped or not funded.

[abacus9900]

The physics and the maths is beyond many, and certainly beyond me; but from a position of ignorance it does seem that the time has arrived for string-theory of some-guise "to put up or to shut up".

You appear to be labouring under the misunderstanding that our science, which has been going in an organized way for a couple of hundred years or so (if that), is in a position to make testable experiments to allow us to make theories about the deepest aspects of reality. This seems totally unrealistic and out of touch to me. The point you and some others here are missing is that ideas like M-theory are a beginning model on which to hang future ideas, perhaps due to new thinking or new knowledge. Where would science be today if people had not asked questions they had little hope of answering at the time? Science is an ongoing process.

[imatfaal]

You appear to be labouring under the misunderstanding that our science, which has been going in an organized way for a couple of hundred years or so (if that), is in a position to make testable experiments to allow us to make theories about the deepest aspects of reality.

Yes, I am labouring under that misapprehension - even the most beautifully self-consistent theory must be able to be tied to lumpen reality.  The experimental evidence for many areas of truly unbelievable and deeply profound physics is astounding.  The LHC is trying, amongst other things, to recreate the conditions of the universe just after the big bang to search for the higgs boson, quantum mechanics in all its wondrous variety is eminently testable, and gr and sr make the world go round. 

This seems totally unrealistic and out of touch to me. The point you and some others here are missing is that ideas like M-theory are a beginning model on which to hang future ideas, perhaps due to new thinking or new knowledge.

And the point you are missing is why should M-theory rather than any other be a starting point for new ideas? Few ideas have had more intellectual weight thrown at them for decades, and yet it is becoming more complex and rarefied rather than concrete and applicable.

Where would science be today if people had not asked questions they had little hope of answering at the time? Science is an ongoing process.

Science would be exactly where it is now - because that is, to an extent, how we did behave.  However, String theory is a question that has been asked - almost ad infinitum - and is yet to yield greater physical understanding.  The mathematics is awesome, the complexity breath-taking, but the results...