don@allegra.UUCP (D. Mitchell) (04/12/84)
Yes, there are serious philosophical problems with quantum field theories. The approach is popular because of the great success with QED and the unification of Electroweak forces. Many physicist feel that QCD, the proposed strong nuclear theory, is correct but difficult to prove. The current approximate methods of evaluating the equations (perturbation theory) give divergent series. There are some very beautiful things about these theories. When one attempts to assemble the minimally complex theory that makes the electron field locally gauge invariant, adding the photon field does it just right. Furthermore, the photon must be massless. With regard to renormalization, it is difficult to make judgements. I think it is possible that a final all-inclusive theory of elementary processes will be found. There is no guarantee that this theory will be intuitive or easy to understand. We are only capable of "understanding" Newtonian physics, and it is just plan incorrect! Since we are dropping names, I recall that Feynmann told us (the field theory class) that he had long been unhappy with renormalization, but that the new formalism that came out of the Weinberg Salam theory had convinced him that it was not just an ad hoc trick. Who knows?