Authors’ Response to Commentaries

According to Wilson (1), ‘‘. . . any plausible unifying theory that seeks to marry longevity, functional disability, and health perception must involve political, social, cultural, psychological, and economic factors.’’ On the contrary, Fries (2) states: ‘‘A general theory of biological aging . . . needs to precede a general theory of population aging, which then could be derived from it, and inconsistencies and contradictions explained.’’ Even, if the latter seems to be tailor-made to answer the former, and vice versa, it is significant that they were both comments on our article, which proposes broad outlines for a general theory on population aging. Their independent suggestions that we did not fully consider the social and political factors as well as the biological factors may indeed indicate that we have achieved a balanced approach. Wilson and Fries are 2 of the 13 scholars, biologists, demographers, epidemiologists, and clinicians, including several geriatricians, who reacted to our proposal, providing together a reasonable sample of gerontological thinking (1– 13). First, we thank all of them for their participation. Their pleasure was obvious and their contributions were, for the most part, positive. We have really enjoyed beginning this debate, although the number of points raised cannot all be answered here. We have therefore selected a few to begin with, and apologize to the remainder. We acknowledge that, at present, our article lacks depth and detail, as underlined by Carnes and Bernard (4), but, again, our aim was to propose the main outline for a general theory of population aging and to open the debate rather than complete it.