  An irreversible thermodynamical theory of solids is presented where the
kinematic quantities are defined in an automatically objective way. Namely,
auxiliary elements like reference frame, reference time and reference
configuration are avoided by formulating the motion of the continuum on
spacetime directly. Solids are distinguished from fluids by possessing not only
an instantaneous metric tensor but also a relaxed metric. The elastic state
variable is defined through comparing these two metrics. Thermal expansion is
conceived as temperature dependence of the relaxed metric and plasticity, an
irreversible change in the relaxed metric, is described via a plastic change
rate tensor. Thermomechanics is built around these -- finite deformation --
kinematic quantities by starting from mechanics and adding thermodynamical
requirements gradually. The obtained theory is not restricted to isotropic
media.
