Intergenerational ethics is the study of our responsibilities to future individuals—individuals (human or not) who are not now alive but will be. The term “future” characterizes, not the kind of a thing, but rather the temporal perspective from which it is being described. Future people, as such, therefore differ from us neither intrinsically nor in moral status. Our responsibilities to them are best understood by attempts to see things from their perspective, not from ours. Though intergenerational ethics takes various forms, the credible forms in conjunction with known facts yield two great practical conclusions: we must reduce human population, and we must keep most fossil fuels in the ground. The demandingness of these conclusions is no objection against them, but rather an accurate measure of the moral burdens of our godlike knowledge and power.