In the commonly used light clock concept, where a photon bounces back and forth between 2 mirrors, it is easy to see how gamma works. Gamma is simply the factor of increase in the distance that the photon has to travel between mirrors. We can fully comprehend why time slows down at the rate that it doe's for the light clock. Are there any known explanations as to why gamma can be used to determine the rate of change in time generally, mass and length in the direction of motion? Real things happen in real ways. Simply knowing a rate of change is not enough. Surely the next questions should be "Why do things change at this rate"? And "What does this tell us about what is really going on at the most fundamental level of physical reality"?