Structure of equations of macrophysics

The first and the second laws of thermodynamics form the constraints on the equations describing macrophysical phenomena. It is argued in this paper that there are some additional universal constraints. These constraints are caused by the Hamiltonian structure of microequations. Previously one feature of micromotion, its reversibility, was used by Onsager to explain the observed reciprocity relations. Hamiltonian structure is richer than reversibility and yields richer consequences. Some of these consequences are a nonlinear version of Onsager's relations, Hamiltonian structure of reversible equations of macrophysics, and quasi-Hamiltonian structure of irreversible equations.