I would expect that a proper elucidation of what string theory really is all about would involve a revolution in our concepts of the basic laws of ph… - Edward Witten

I think one has to regard it as a long term process. One has to remember that String theory, if you choose to date it from the Veneziano model, is already eighteen years old... that quantum electrodynamic theory towards which Planck was heading [in 1900], took fifty years to emerge.

Even though it is, properly speaking, a postprediction, in the sense that the experiment was made before the theory, the fact that gravity is a consequence of string theory, to me, is one of the greatest theoretical insights ever.

... one thing that's worth mentioning, though, it that apart from the dream of understanding physics at a deeper level involving gravity, work in string theory has been useful in shedding lights on more conventional problems in quantum field theory and even in and as well with applications to mathematics. Apart from its intrinsic interest, those successes are one of the things that tend to give us confidence that we're on the right track. Because, speaking personally, I find it implausible that a completely wrong new physics theory would give rise to useful insights about so many different areas.