...we have gone in different direction, sacrificing theoretical adequacy for simplicity
we shall choose a relativistic theory which is naive and obviously wrong in its simplicity,
but which is definite and in which we can calculate as many things as possible – not expecting
the results to agree exactly with experiment but to see how closely our
''shadow of the truth'' equation gives a partial reflection of reality.
R. Feynman, M. Kislinger, F. Ravandal, Phys. Rev. D3, (1971) 2706