Dagfinn Føllesdal

Much of Essler''s work has been devoted to bringing science andphilosophy together for the purpose of conceptual clarification. Oneparticularly interesting area for such cooperation between science andphilosophy has been relativity theory. In this paper I will consider oneinstance of such interplay: the transformation that our notions of rotationand rigidity have undergone in general relativity and what this process canteach us. I will start by saying a little about the physics of the situation andthen go on to some philosophical observations about meaning and theory.