Space and time and the even more basic notion of spacetime, and the structures assigned to them, belong to the most fundamental concepts of science. So far, every physical theory of some generality and scope, whether it is a classical or a quantum theory, a particle or a field theory, presupposes for the formulation or its laws and for its interpretation some spacetime geometry, and the choice of this geometry predetermines to some extent the laws which are supposed to govern the behaviour of matter, the laws of primary concern to physics. Thus Galileo's assertion¹ still applies: "He who undertakes to deal with questions of natural sciences without the help of geometry is attempting the unfeasible."