http://en.wikipedia.org/wiki/Richard_Feynman
Shortly before his death, Feynman criticized string theory in an interview: “I don’t like that they’re not calculating anything,” he said. “I don’t like that they don’t check their ideas. I don’t like that for anything that disagrees with an experiment, they cook up an explanation — a fix-up to say, ‘Well, it still might be true.’” These words have since been much-quoted by opponents of the string-theoretic direction for particle physics.
[end quote]
more generally, see also:
“Cargo Cult Science”, by Richard Feynman
http://wwwcdf.pd.infn.it/~loreti/science.html
Appreciate the ping.