This article reviews the relevance of modern theories of polymerized matter based on structureless, flexible molecules to the understanding of basic experimental observations which are made on polymer solutions, rubbers, glasses and crystals. General phenomena such as the viscosities of polymer solutions and the origins of rubber elasticity are described satisfactorily by the theories. We await a suitable treatment of the glassy state. and the approach has only descriptive value when applied to crystalline polymer systems.