Paul Zielinski "It's actually about finding ways to adapt one's own theory to contrary observations, and proving *other* people's theories wrong. Popper's view of this is just not realistic IMO. The real issue is, what kinds of post-hoc modifications are allowed, and which are not? And why? And what exactly makes a scientific theory falsifable? The answers to these questions are not at all obvious."
Jack Sarfatti "In the end it's always a personal judgment call in a complex situation. Basic rules of Popper are good - Feynman told me he accepted falsification rule as essential to good physics. Then we have Einstein's rule that the theory should be as simple as possible without being simpler than is possible. String theory fails on both counts so far. The decisive rule is to predict something important before it's observed. My unique prediction that dark matter particles whizzing through space do not exist in sufficient numbers to explain the data is testable i.e. falsifiable in Popper's sense - and it stands alone against the crowd of Pundits. My theory says dark matter is a virtual particle effect inside the vacuum in which the bosonic positive vacuum zero point pressure exceeds the fermionic negative zero point pressure on shorter scales - opposite on larger scales of course."
Konstantine Klado "Whats the reason to quantize gravity in the first place? Riemann geometry is already complicated. Why can't one just figure out how to do quantum mechanics in curved spaces?"
Jack Sarfatti "How to do the quantum mechanics of non-gravity fields in classical Riemannian curved geometry is well understood - textbooks etc, the problem is how to quantize the curved spacetime itself. An associated problem is whether it should be quantized to begin with if it is an emergent macro-quantum coherent collective effect from the random micro-quantum substrate of all the other quark-lepton spinor-electro-weak-strong boson non-gravity fields in the pre-inflation false vacuum. Gravity would then be similar to the zero resistance electrical currents in a superconductor and to the crystal distortion fields etc.- results of what is called spontaneous broken symmetry in the inflationary phase transition from the false to true vacuum leading to the hot Big Bang.
There are arguments of consistency that classical gravity must be quantized. However, they are not conclusive. Direct quantization of gravity gives an un-renormalizable theory with uncontrollable infinities in the mathematics that basically is inconsistent like dividing by zero.
Gravity is a force in Newton's theory. Most high-energy theorists do not take courses in Einstein's gravity so they think of the problem in Newtonian terms and that's where a great confusion sets in. Although Einstein's equations limit to Newton's the conceptual idea of gravity in Einstein's theory is qualitatively different from Newton's.
Oh you meant brane theory. I think it's like financial derivatives on Wall Street.;-) Rube Goldberg, little bang for big buck, contrived, excess formal baggage, like Copernican epicycles, too many fudge factors and probably unnecessary. Mathematicians in physicist's clothing gone wild on an acid trip! Pipe dreams - well when they actually predict something subsequently observed in LHC etc then I will eat my beret. Meantime I am not betting on Lisa Randall's "Warped Passages" for example as anything other than science fiction."