The dramatic increase in life expectancy confuses people. In the United States at the turn of the twentieth century, the average life span was about 45 years. Now people are expected to live up to 78.5 years. That has spurred an unwarranted optimism, when in truth, the overwhelming majority of the increase is the result of a decrease in infant mortality.

At the turn of the twentieth century, about 10 to 15 percent of all children died before their first birthdays, mostly from infectious diseases. But because of medical advances, today less than one percent of children die before their first birthdays. Thus, Olshansky and Carnes point out in their book The Quest for Immortality, “The rise in the life expectancy has slowed to a crawl.”

Another thing that confuses people is thinking that if we could cure cancer, most of us would live many more years. Not true. In fact, Harvard demographer Nathan Keyfitz calculated that if researchers cured all forms of cancer, people would live only a measly 2.2 years longer before they died of something else! Unless science cures the majority of all diseases, as author Stephen Cave writes, “Then the result is not a utopia of strong-bodied demigods but a plethora of care homes and hospitals filled with the depressed, the diseased and the incontinent old.” In that case “it is not about living longer but dying slower.”