ABSTRACT
The gerontologist Sacher (1) noted that there are different theoretical frameworks within which biological research on aging can be considered, each of which is associated with what he termed a “primitive” question. The best known is the conventional aging-oriented approach designed to address the question “Why do we age?” Sacher notes that this is an ontogenetic issue and the attack on it is guided by a research paradigm concerned with molecular, genetic, and physiological processes. The basic experimental approach to this question involves the comparison of specific functions or structures in old and young animals such as mice. However, he observed that this far-reaching correspondence between laboratory rodents and humans concealed a paradox: if these two species are so similar in molecular, cellular, and physiological makeup, the data on the ontogeny of aging in rodents brings us no closer to understanding why a rodent grows as old in two years as humans do in 70 years. Thus, the second approach to aging research flows from this paradox and is designed to address the longevity-oriented question: “Why do we live as long as we do?” This question cannot be answered within the framework of ontogenetic research on aging but rather requires the development of an evolutionary-comparative paradigm. But then, a third approach to aging research is death oriented and is designed to answer the question “Why do we die?” which is a problem separate from aging and longevity; there is no necessary relation between aging and dying. None of these questions by themselves adequately frames the field of aging research because, although there is obvious overlap, they each possess different conceptual centers-evolutionary (life span), physiological (aging), and death (stochastic).
