>>One day the speed of light might be measured with a ruler and a clock. The next day, if the same measurement gave a different answer, no one could tell if the speed of light changed, the ruler length changed, or the clock ticking changed.
>
>I guess that is why it is called "Special Theory of Relativity" and not the "Special Theory of Absolutes". :)
But in case of an absolutist ruler... don't we have a contradiction?