According to Dyson, Feynman in 1948 related to him a derivation, which, from
1) Newton's: m\ddot{x}_i=F_i(x,\dot{x},t)
2) the commutator relations: [x_i,x_j]=0m[x_i,\dot{x}_j]=i\hbar\delta_{ij}
deduces:
1) the 'Lorentz force': F_i(x,\dot{x},t)=E_i(x,t)+\epsilon_{ijk}\dot{x}_j B_k(x,t)
2)...