  The central role that group theoretic techniques played in Weyl’s  analysis of spacetime was one of several factors which led Weyl to  his general theory of the representations and invariants of the  classical Lie groups. It was in the context of Weyl’s investigation  of the space-problem (see §4.2) that Weyl came to appreciate the value of group theory for investigating the mathematical and  philosophical foundations of physical theories in general, and for  dealing with fundamental questions motivated by the general theory of relativity, in particular. 