  A system containing a pre-steady state standard (non-autocatalytic) reaction,
with multiple paths, evolves toward a kinetic state with the minimum attainable
activation free energy. Displacement of the path frequency distribution in this
transition was shown to minimise the affinity linked to this change in
activation free energy. In damping this scalar force, a standard system is
driven along a path of least action, as previously established for a system of
competing autocatalytic reactions. A kinetic source of time asymmetry arises
within the system, as the activation affinity moves the system toward the most
probable distribution of reaction paths. As the functions of state are not
changed by path displacement, a change of kinetic state cannot produce chemical
work. This generalises the notion of force to a scalar quantity responsible for
a displacement that does not yield work or heat. Spectrophotometric
observations reported on the transition to steady state kinetics during
dinitrophenyl phosphate phosphorolysis confirmed that time variations in the
activation affinity are non-positive.
