ABSTRACT
Why do we age
?” Sacher notes that this is an ontogenetic issue, and the attack on it is guided by research paradigms 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 little closer to understanding why a rodent grows as old in 2 years as humans do in 70 years. Thus, the second approach to aging research flows from this paradox and is designed to address the longevityoriented 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 deathoriented 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 frame 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).
