Why Do We Die? Economics, Biology, and Aging

Why do we die? Why, to be more precise, do we age, in the sense that our mortality rate rises rapidly in a terminal phase of life? One way to illustrate the effect of aging on longevity is to calculate the life expectancy of nine-year-olds if they could sustain their current mortality rate. For the US population in 2003, this life expectancy would be just over 7,000 years (see Centers for Disease Control 2006). That is, we would not be immortal, because there is still a constant positive probability of dying. Our lives would be vastly longer, however, if mortality risks did not increase with age. In fact, 2 percent of the population of nine-yearolds would live to almost 30,000 years of age. Mortality has been modeled as endogenous within economics. Previous literature has taken