Arthur Eddington Quote
The velocity of light plays a conspicuous part in the relativity theory, and it is of importance to understand what is the property associated with it which makes it fundamental. The fact that the velocity of light is the same for all observers is a consequence rather than a cause of its pre-eminent character.
Space, Time and Gravitation: An Outline of the General Relativity, Theory, Chapter III (p. 59)
