"Would you take a billion dollars, if as part of the deal the Earth were made uninhabitable a year after your death? ... well, of course not; you care about your friends, above all your children, any grandchildren. But ... what if the deal calls for the planet to be poisoned a thousand years later? We feel strong obligations to generations in the near future - should we not feel the same way about our children's great-grandchildren and generations beyond them?"