In experimental philosophy we are to look upon propositions obtained by general induction from phenomena as accurately or very nearly true . . . till such time as other phenomena occur, by which they may either be made more accurate, or liable to exceptions. —Sir Isaac Newton, Principia (1686)

The relativity theory arose from necessity, from serious and deep contradictions in the old theory from which there seemed no escape. The strength of the new theory lies in the consistency and simplicity with which it solves all these difficulties, using only a few very convincing assumptions . . . The old mechanics is valid for small velocities and forms the limiting case of the new one. —A. Einstein and L. Infeld, The Evolution of Physics (1938)