The light clock and time dilation.

ehj

How do you argue that the equation for time dilation derived from studying a light clock can be used in general. For instance, how does it tell us that a mechanical clock would also show time dilation?

Ich

If it were different, the principle of relativity would be violated - whenever both would not agree, you could tell that you are moving in an absolute sense. This principle is postulated in the development of the theory.

bernhard.rothenstein

I think that the weak point of the light clock consists in the fact that it is not a wrist watch involving two such clocks located at the two mirrors respectively.

country boy

A clock is a device that counts cycles, where a motion repeatedly returns to a starting point in some frame of reference. The light clock is a special case of this. Maybe instead of questioning the generalization of the light clock to all clocks, we should simply be amazed that such a generalization is possible. It tells us something profound about the universality of physical processes.