Let the principle of detailed balance be valid. Then, for small deviations from equilibrium, the kinetic response of the system can be approximated as linearly related to its deviation from chemical equilibrium, giving the reaction rates for the generalized mass action law as: w r + = w r e q ( 1 + ∑ ∑ i α α r i ( μ μ i − − μ μ i e q ) R T ) ; w r − − = w r e q ( 1 + ∑ ∑ i β β r i ( μ μ i − − μ μ i e q ) R T ) ;