One of the big questions for people who believe in extra dimensions is: Why don’t we see them? Sure, we have methods for hiding them, usually by making them really tiny, but then we need to ask: Why are they tiny?

One could just as easily be alluding to `sparticles’ instead of extra dimensions, since the consistency of `Super’String theory hangs by SUSY’s thread: If it breaks, and no LHC evidence for sparticles emerges, than this physical house of cards collapses completely, or degenerates to a shell game:”Just wait until the ILC fires up..!
Small wonder the term `M-theory’ was invented and `String Theory’ is spoken of, in lieu of the SST word.
At least Sean’s paper is NOT predicated upon the ludicrous notion of a negative cosmological constant, so dear to the stringers. AdS space is blatantly in contradiction to observations, yet because of its special relation to CFT, it is kept alive on life support.

It’s well known that turning on, say, a 4-form or 7-form flux in M-theory automatically turns an 11-d flat space into AdS_7XS^4 or AdS_4XS^7, thus dynamically compactifying some dimensions into a sphere. I think that the zeroth order question is “How do you get a positive Lambda in your D dimensional lagrangian?”. Are you implying that susy is somehow badly broken at some high scale even before you get compactification?