Discrete Time as Causal Interaction: A Framework from the Planck-Einstein Relation and Special Relativity

We derive the discreteness of time from two empirically established results of Einstein (1905): the photoelectric effect (energy is quantized) and special relativity (time is relative to the observer's frame). The Planck–Einstein relation E=hf and mass–energy equivalence E=mc2 jointly yield a characteristic frequency f=mc2/h and a minimum temporal resolution T=h/mc2 for any energy packet of rest mass m. Combined with a principle of ontological parsimony excluding unobservable continuous background time , we propose that time does not exist as a continuous substrate but emerges as the discrete sequence of causal interaction events between energy packets.