String Theory: Background Dependence & Complaints

[Ratzinger]

What actually is the reaction of string theorists to the complaints that their approach is not background independent? Why is it not such a big concern to them?

 

[Demystifier]

It IS their concern. Unfortunately, they do not know how to solve this problem. Nevertheless, that is not a reason to reject string theory and accept loop quantum gravity. This is because string theory is MUCH MORE than a quantum theory of gravity. String theory and loop quantum gravity are NOT too different approaches to the same problem.

 

[Fra]

On "The case for background independence", Smolin
http://arxiv.org/PS_cache/hep-th/pdf/0507/0507235v1.pdf

I've seen at least one response from some string theorist
"The case for background independent theories and formulations with background",
http://mathphys.iu-bremen.de/~robert/background.pdf

I'm sure there are lots of string responses to Smolins paper though.

/Fredrik

 

[f-h]

"string theory is MUCH MORE than a quantum theory of gravity."

For a physicist that's not neccessarily a good thing of course. We have good reason from established physics to expect a theory of QG to exist in reality, we don't have any physical reasons whatsoever to believe that anything else that ST is exists.

 

[Fra]

It IS their concern. Unfortunately, they do not know how to solve this problem. Nevertheless, that is not a reason to reject string theory and accept loop quantum gravity.

I don't think we need to narrow it down to just two options do we? Perhaps the are other options.

To me at least, there is sufficient issues all over the place for me to motivate a rethinking of the fundaments of physics and it's methods, and and that point I think the options are more than the two mentioned. Part of my motivation is that the foundational physics touches the scientific method and is thus to me at least more than just the traditional physics. Natural extensions I want integration in foundational physics is generic evolutionary models, touching also highly complex physical systems such as the human brain. We may well end up dynamically modelling the models to an even larger extent. In that perspective, string theory is not what comes to my mind. But then that's just a single opinion.

/Fredrik