[oldandtired]

One problem with your explanation is that the muon and the tau (and the pion as a decay product of the tau) all decay into electrons, neutrinos and photons, which would suggest that neither muon or tau are fundamental.

This would put the fundamental leptons being only the electron (and its antiparticle) with the neutrino and the photon.

Such an idea would upset the "symmetry" model.

[at_a_remove]

I never suggested that they are fundamental, and nobody said that the symmetry is perfect. In fact, the way the various symmetries break is what gives rise to all of this complexity and only raise more questions.

Also, photons are not leptons -- wrong spin for that. Which in turn can raise yet another axis for our funhouse of mirrors: fermions versus bosons.