Man, machines, manufacturing, and maintenance: merits of a much-maligned metaphor.

277 W OK, STRICTLY IT IS AN ANALOGY rather than a metaphor, but I couldn’t resist. In overview talks on the “SENS” repair-andmaintenance approach to combating aging that I favor, I generally introduce the basic concept by analogy with the fact that the functional lifespan of a car may be made unusually long by sufficiently comprehensive maintenance. I use this analogy to explain not only why a rejuvenation approach to combating aging is plausible, but also to contrast it with the more preemptive approach preferred by most biogerontologists and the less preemptive approach of geriatrics. I am persistently surprised at the resistance I encounter to the validity of this analogy, so I think it is time to explain why I find it so useful. The validity of this analogy determines the applicability to gerontology of a wealth of evidence from our experience of man-made machines, so it may conspicuously affect ethical judgments1–3 and public policy.3–6