I understand that the speed of light c is derived from the self-interaction between elections/photons, and is thus the maximum speed of anything composed of electrons/photons.
Suppose that there is a particle that is made up of stuff that is not electrons and photons. Is it possible in principle for this particle to travel faster than c? Or does c somehow apply to absolutely everything in the universe, even as yet undiscovered particles?
If it has already been proven that c applies to absolutely everything in the universe, even as yet undiscovered particles, then c is really a property of space itself, rather than a property of electromagnetism.