  Given a fine-scale physical theory characterized by an evolutionary system of
equations and a set of quantities, defined from the variables of the fine
theory, that serve as a coarse representation of the fine scale phenomena, a
systematic method for developing an evolutionary set of equations for the
coarse quantities is presented. This set may be considered as governing
equations for a coarse theory corresponding to the fine one since the solutions
of the coarse theory define a small class of solutions to the fine theory. The
method for generating the coarse theory is technically straightforward. The
conditions required for the procedure to succeed are understood qualitatively,
but a rigorous result for the intended applications, is not known - hence the
method is formal. The method is illustrated on a few model problems.
