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Why string theory doesn't explane all?

  1. Aug 28, 2013 #1
    Why string field theory doesn't explane a black singularity but its called the theory of everything?

    It just explanes quantum gravity not why the universe exists or why we exist, what Im tring to say is that it should not be called the theory of everything.
  2. jcsd
  3. Aug 28, 2013 #2


    Staff: Mentor

    Why do you think it doesn't explain a Black Hole singularity? My understanding is a number of conjectures within string theory (eg its made out of strings) does explain it but much more work needs to be done - right now its up in the air.

    For example check out:

    Its called a theory of everything because of what it attempts do do - whether it is or not remains to be seen.

    Last edited: Aug 28, 2013
  4. Aug 28, 2013 #3
    String theory, besides Phenomenological problems such as supersymmetry and extra dimensions, is far from a theory deserves to be called a theory of everything!
    it doesn't explain quantum gravity as you said because QG has a number of conceptual problems such as "the problem of background independence", "the problem of time", etc that string theory doesnt' have any answer to them. for example the current consensus in fundamental physics community is that if a theory of QG exists, it must be background independent so if QG be a QFT, one must define a generally covariant QFT without background which is a concept that is not properly formulated (I guess there are several attempts in LQG community) because it is very different from conventional QFT's and there is no background indepedndent formulation of string theory and some attemps to construct such a theory using simpler models such as topological strings theory and topological M-theory hasn't been so successful! there was a hope in the last years started at mid 80's that when one quantized string theory in the spectrum of resulting theory, there are particles behave like a spin 2 particle like graviton and some gauge fields like Yang-Mills and in this sense string theory is a theory of QG which seems more like a joke! these are outside problems that string theory must face beside some inside problems of the string theory itself! for example :

    1) the problem of number of vaccum solutions of M-Theory;
    2) one doesn't not know what is the classical theory of gravity in string theory because in classical sting theory, one doesn't have gravity at all! like YM theories that approximated by Nonlinear Born-Infeld fields
    3) the dynamics of second quantized string theory (string fields) hasn't been understood except some simple ones such as Witten cubic open string field theory
    and ...

    so it is far from a complete theory if it be a well-defined theory at all!
    Last edited: Aug 28, 2013
  5. Aug 28, 2013 #4


    User Avatar
    Science Advisor
    Gold Member

    String theory is so complicated no [realistic] definitive test has yet even been proposed. It's such a slippery eel, it appears bulletproof. The real question, IMO, is whether it's even definable.
  6. Aug 29, 2013 #5
    Its strange after decades we still couldn't figure them out, even there is a theory.
  7. Aug 29, 2013 #6


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    Staff Emeritus
    Science Advisor
    Homework Helper

    The word is 'explain', or 'splain if you are in a hurry.
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