The paper studies the sensitivity implications of the class of monotone social preference orders on infinite utility streams which satisfy the axioms of Equity (Finite Anonymity) and Stationarity (Independent Future). The principal result of this investigation is that representability of such preference orders implies a certain lack of sensitivity to the utility stream of any finite number of generations, which we refer to as ‘insensitivity to the present’. Our result points to a fundamental difficulty in implementing the sustainability principle, which requires intertemporal social preferences to reflect fairly the interests of the generations in the present and in the future.
