... Feyn-man soon learned that there was a great obstacle to this delayedaction-at -a- distance theory: namely, if a radiating electron, say inan atom or an antenna, were not acted upon at all by ... causality states that all observable effectstake place at a time later than the cause, Maxwell’s equations forthe electromagnetic field possess a radiative solution other than thatnormally adopted, ... make a corresponding quantum theory. To treat a classical system of interacting particles, there are avail-able analytic methods using generalized coordinates, developed byHamilton and Lagrange,...