>>14151057Maxwell's equations in the absence of a source follow from the existence of a massless spin 1 particle (the photon). When you couple that to a charged spin 1/2 particle (the electron), you get all the main features of the classical idea of electricity and magnetism. Quarks aren't necessary to derive all the stuff you're after.
That said, it may be possible to show that even these assumptions force the existence of quarks, but I'm not aware of that.
