In this paper we introduce a new geometric object, the physical metric
, g, for the measurement of distance between material particles in the
reference configuration. We then treat g as an internal variable and
thereby obtain hereditary constitutive equations for dissipative solid
s under conditions of large deformation. We demonstrate that g is in f
act a measure of non-affine deformation and introduce the concept of t
he hypercontinuum which allows the existence of multiple velocities in
a material neighborhood, thereby leading to a deformation field with
multiple metrics.