But here is a simple truth that many of us seem to resist: living too long is also a loss. It renders many of us, if not disabled, then faltering and declining, a state that may not be worse than death but is nonetheless deprived. It robs us of our creativity and ability to contribute to work, society, the world. It transforms how people experience us, relate to us, and, most important, remember us. We are no longer remembered as vibrant and engaged but as feeble, ineffectual, even pathetic.

I am talking about how long I want to live and the kind and amount of health care I will consent to after 75. Americans seem to be obsessed with exercising, doing mental puzzles, consuming various juice and protein concoctions, sticking to strict diets, and popping vitamins and supplements, all in a valiant effort to cheat death and prolong life as long as possible. This has become so pervasive that it now defines a cultural type: what I call the American immortal.