"Longitudinal or serial altruism, that is, altruism toward the generations in future time, arises, like lateral or space altruism, thru sympathy, that is, thru the imagination. The living sustain a vital relation to the unborn. Every one who recognizes and shows any regard for this relation, and there are very few who do, does so by putting himself in the place of the unborn billions, and by anticipation sharing their welfare and ill-fare."