I like this (question to Ed Witten after his talk):
The question session was unusually sceptical and challenging, beginning with a very hostile and long-winded question about whether he wasn’t worried that he had led physics down a 30-year path of failure. Unfortunately the questioner was intent on making a hostile speech, and much time was wasted trying to get him to shut up so that Witten could address the question.
Here is the question of Alexander Unzicker (who wrote a few critical books about developments in modern theoretical physics (alas for most of you in German…)):
This was an impressive talk. I am sure many people are impressed. I am also sure that with your work you are making the best out of your extraordinary capabilities.
I am not quite sure however that you are fully aware of the responsibility towards science, the search for the laws of nature…. It was Isaac Newton who said Nature created everything by number, weight and measure. Thus it is the theorist’s business to predict numbers the experimentalist’s business to measure these numbers. And as everybody can see supersymmetry and string theory in the past thirty years did not deliver a single result which Isaac Newton had called physics.
So, aren’t you afraid of being the scientific leader of an entire epoch of physics that might lead to nowhere? Aren’t you afraid of misguiding the concentrated intelligence of seven billion people on a planet? (chairman tries to interrupt)
Of course, nobody can prove you wrong, but it’s the history of science which gives a clear indication: the real revolutions of physics have always been pushed forward by sceptic individuals, never by the euphoria of the many. And this is where your problem lies.
Your risk is that you are playing mathematical games of with their link to reality is still a promise, concepts of which the link to the physical reality you do not understand. Thus I’d like to urge you to reflect upon your role in science. Please, get back to reality.
I do not quite agree, but grosso modo I do.