>>>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.
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>>I guess that is why it is called "Special Theory of Relativity" and not the "Special Theory of Absolutes". :)
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>But in case of an absolutist ruler... don't we have a contradiction?

Not if the ruler is your relative. :)