# The impenetrable mysterys of String theory

1. Jul 21, 2007

### Schrodinger's Dog

I once got into a very heated debate with some string theorists, about string theory, saying that I doubted it would ever pan out, not that it may never have any use, but questioning why it gets so much attention and yet has nothing to show for itself? now it is impossible to say never but that it is unlikely we will ever find evidence for it, string theory has been around for a over 30 years and as yet nada, it's still technically a hypothesis not a theory.

Now one thing that bothered me was that I was told that I could not judge a field unless I'd studied the maths of string theory, as most people know this is post grad mathematics, usually either studied in the maths dept of the university, or sometimes in the physics dept. Although I understand how it works at a basic level, tightly wound dimensions that get rid of infinities that plague GR and QM, you know a solid overview, I don't know the impenetrable maths.

Now here's the paradox, why would you study a subjects maths if you did not believe would pan out anyway, in order to more accurately criticise why it wont pan out, isn't this a waste of time?

And that's not all, String Theory is impenetrable to all but a few, who are of course, since they are studying it, ardent supporters, so how in fact does one go about criticising string theory and does it enjoy a certain immunity from criticism because it is so esoteric.

I have seen people who have basically become disheartened by string theory criticise it, and rather successfully, although generally they are ignored, but do you think this is one of the reasons this as yet unproveable dream has such longevity. The very fact that it does not open itself to criticism because of its nature. Unlike say QFT or GR were the majority of scientists have a deep understanding of it.

Just something that has kind of been tugging at my mind?

Anyone think string theory still has legs? I'm sure there are some people on this forum studying it as we speak, who deeply believe it may be useful, nay is useful. Can anyone explain to me why it has been given so many chances to prove itself?

Last edited: Jul 21, 2007
2. Jul 21, 2007

### G01

I can't really help explain why string theory has lasted but I wanted to say something about that argument for criticizing string theory. That is not a valid argument. You do not need to understand all the math of the theory to criticize it. I do not understand all the maths, yet I still know that there is still no experiment able to test it. (We may eventually be able to test it, but as of now we can't.) I don't need to study graduate level topology to see the lack of experimental evidence.

Last edited: Jul 21, 2007
3. Jul 21, 2007

### Schrodinger's Dog

Oh yeah, but to understand why it may well not pan out particularly where it attempts to apply itself to quantum field theory, you need to know the maths. This was kind of the argument, I couldn't make judgements because I didn't know enough, thus the "paradox". It's a sort of self granted immunity, only string theorists or believers could criticise it and they seldom do.

4. Jul 21, 2007

### Danger

I disagree with that. Learning the basis of anything, whether 'true' or not, can give one the tools to explore the field more and possibly come up with the real answer. No learning is a waste of time.
Incidentally, though, I thought that 'Brane Theory supplanted String Theory years ago.

5. Jul 21, 2007

### Schrodinger's Dog

M-Brane theory is a son of String theory anyway, it's just a progression. I didn't say it was useless I just said it may not pan out as a theory in science. No one can make that judgement about any field of maths. One day n dimensional topology and strings may find an application just like imaginary numbers eventually did nearly three hundred years or so after their conception.

6. Jul 21, 2007

### Danger

The limits of my education are no secret... I don't know what an 'imaginary number' is.
And I certainly didn't mean to imply that you sounded Draconian in your comments about String Theory. I just can't see any way in which learning anything can be considered a waste of time.

7. Jul 21, 2007

### Schrodinger's Dog

I see, but say I'm not really interested in it and would rather pursue some hypothetical career in mainstream physics, then it may be a waste of my time, not that the subject is but just for me personally. Because at the end of the day I would not wish to utilise it any way except to criticise it, so it would be better to not go into it. I really don't mean to infer that it is a waste of time in general.

Imaginary numbers are the result of

$$x^2+1=0$$

ie square root of negative numbers, I'm sure you know that -12=1 but what if it equalled -1?

It opens up another dimension on a graph, it's used a lot in physics in the Schrodinger equation for example.

it also can be used to derive all the trignomoetric funcitons so it's actually very useful.

[itex]e^{i\pi}+1=0[/tex]

Where i is imaginary

In particular.

Last edited: Jul 21, 2007
8. Jul 21, 2007

### cristo

Staff Emeritus
Of course to study string theory, one needs to have studied QFT and GR, which are assumed to be the basis of any unified theory. Then, as danger mentions, studying string theory in depth will give more chance to pick errors in it, or different paths on which one could possibly travel.

You're joking, aren't you?

Incidentally, have you read smolin's book? There are a few posts on it in the beyond the standard model forum.

9. Jul 21, 2007

### Danger

Ahhh, I see. You're talking about formal learning, as in classes that you don't care about, when you could be taking other classes that you do care about? In that case, I agree that it would be a waste. Sorry that I misunderstood the first time.

edit: Holy ****, you guys have been busy! Schrodinger, I'll take a look at your edit about imaginary numbers sometime when I've had a little less tequila. I only have another 3 hours at work, so when I get back to beer at home I'll take a shot at it. For one thing, I'll need a magnifying glass. I can't read that second equation that you put up, with the E(i something) superscript. (eieio? Where's the duck?)

Last edited: Jul 21, 2007
10. Jul 21, 2007

### Schrodinger's Dog

Ok not all but let's face it, QFT is a very open field where criticism is well received, string theory is criticisable only by string theorists or that's what they tried to claim to me. And of course string theorists do not generally criticise because of their innate bias.

I've read one of his papers that critiques it, rather damagingly I thought at least with my limited understanding, but that hasn't seemed to damage the vigour with which it is pursued. To those who still pursue it, or those I have spoken to, they appear bullet proof.

Last edited: Jul 21, 2007