Any large-scale change in human behavior will literally change the human race: Because such a change alters the conditions under which individuals are conceived, our grandchildren in one scenario will be different people from those in another. This is particularly true in sweeping policy matters such as the environment, global warming, etc.

This seems to suggest that we needn’t feel guilty about our poor stewardship. The descendants who would benefit by our reform are different from those who will suffer at our neglect–and we owe a duty only to the latter.