Starting from the equations for turbulence, relations are derived which allow the computation of the correlation function of turbulent modes. This is achieved by using the following ideas: (1) The turbulence equations are interpreted as stochastic equations. (2) The directness of interaction of the different modes is ordered according to the number of modes necessary to establish the feedback of a given mode on itself. (3) A non-Markovian dynamical friction is introduced and is determined by the condition that the average stochastic force should be zero. In lowest order, Kraichnan's direct interaction approximation is recovered.