What I am wondering is this.
To me, the concept of the exchange of photon that the QED theory says can explain the interaction between two electrons, seems to lack its foundation, and seems to be almost ad hoc and dogmatic. Is the concept of exchange of photon well established? Don't you have any doubt on that theory? Can anybody show me the calculation that starts from the equations that describe the echange of photon to the equation of Coulomb's law of inverse squared force between two electrons?