This article considers a new concept of social optimum for an economy populated by agents with heterogeneous discount factors. It is based upon an approach that constrains decision rules to be
temporally consistent: these are stationary and unequivocally ruled by the state variable. For agents who
differ only in their discount factors and have equal weights in the planner's objective, the temporallyconsistent optimal solution produces identical consumption for the agents at all time periods. In the long run, the capital stock is determined by a modified golden rule that corresponds to an average-like summation of all discount factors. The general argument is illustrated by various two-agent examples that allow for an explicit determination of the temporally consistent decision rules. Interestingly, this temporally consistent solution can be simply recovered from the characterization of a social planner's problem with variable discounting and can also be decentralized as a competitive equilibrium through the use of various instruments.