"The fantastic 12-digit agreement between the theoretical predictions of QED and the experimental results is a miracle. It would be good for physicists to acknowledge the unsatisfactory mathematical structure of this prediction. It starts from a mathematically undefined Feynman Integral, proceeds by making many very complicated manipulations, and ends up with a formal series that Dyson showed to be divergent! Physicists think of it as an asymptotic expansion, but they have no mathematical proof of this. I often joke that this agreement of theory and experiment is a new proof of the existence of God and that she loves physicists!"