Concern for the rapidly growing scale and intensity of the human exploitation of the environment, in particular the alienation of natural ecosystems, but also resource exhaustion, pollution, and congestion, leads one to wonder about the short time. horizons allowed for in decision making. Time preference is dictated by the rate of interest, allowing in practice a horizon often not exceeding several decades. I argue that this is unsatisfactory. Some minimal social rate of discount should not be enforced. Instead, it is (...) more feasible to set absolute environmental standards, thereby introducing quantity constraints on our decision making, within which time preference can be permitted to find its own level. This acknowledges that the myopia of human vision may not be a flaw but rather a biological design which has served us weIl in evolution. It may, therefore, be better to change the rules by introducing self-imposed collective constraints than to try to change the shortsightedness of people in their day-to-day grass-roots decision making. (shrink)