Classical kinetic network theory is well suited to explain elasticity of elastomers and polymer melts qualitatively. However, later refinements of theory have resulted in incommensurate models of either rubbers or melts. By reviewing the concepts of ＇damping function＇ and ＇molecular stress function＇ in polymer melt rheology, a unifying strain measure for both melts and rubbers is presented. For transversely isotropic deformations, damping functions of melts and rubbers are compared, and (un-)surprising similarities are found.