A puzzle about the demands of morality

Two thought experiments are provided which elicit what appear to be opposing judgments about the demands of morality. One Unger-inspired thought experiment suggests that a person must give up four decades of earnings just to save a single life. The other evokes the contrary intuition that one doesn't have to labor forty years without compensation in order to prevent the death of an individual. However, considerations of consistency do not demand that we abandon one of our intuitive responses. This is because there is a morally significant difference between the two burdens that the people suffer in the respective thought experiments. The difference is a result of human psychology being such that it is easier to bear the aftermath of an event that renders one's earlier efforts futile than it is to suffer identical efforts going unrewarded in the future. A conclusion that can be drawn from this temporal asymmetry is that while morality is not quite as demanding as Unger and many consequentialists maintain, it is much more demanding than many of their opponents realize.