Experimental and empirical approaches in the study of aging.

Two approaches to the study of aging are contrasted. The results and implications of the gene-by-gene, hypothetico-deductive molecular genetic approach are compared with studies engendered by unique empirical findings. The former hypothesis-testing approach examines the changing phenotype that results from alterations of the genome and measures the relevance of a gene by the effectiveness with which it alters life-span. Investigations of empirical demographic and physiological puzzles that have come to light in aging studies, examine these phenomena for the broader understanding they bring rather than the knowledge of specific causative genetic elements. While the former hypothesis testing method requires caution in interpretation of results and conclusions, it has been highly informative. Studies of empirical phenomena have necessarily progressed more slowly, but have also yielded substantial gains. Both approaches have advanced the understanding of the aging process from distinctly different but complementary viewpoints.