Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

So do those of us who survive the ordeals of childbirth and childhood today live any longer than the survivors of earlier eras? Yes, much longer. Figure 5-4 shows the life expectancy in the United Kingdom at birth, and at different ages from 1 to 70, over the past three centuries.

Figure 5-4: Life expectancy, UK, 1701–2013

Sources:Our World in Data, Roser 2016n. Data before 1845 are for England and Wales and come from OECD Clio Infra, van Zanden et al. 2014. Data from 1845 on are for mid-decade years only, and come from the Human Mortality Database, http://www.mortality.org/.

No matter how old you are, you have more years ahead of you than people of your age did in earlier decades and centuries. A British baby who had survived the hazardous first year of life would have lived to 47 in 1845, 57 in 1905, 72 in 1955, and 81 in 2011. A 30-year-old could look forward to another thirty-three years of life in 1845, another thirty-six in 1905, another forty-three in 1955, and another fifty-two in 2011. If Socrates had been acquitted in 1905, he could have expected to live another nine years; in 1955, another ten; in 2011, another sixteen. An 80-year-old in 1845 had five more years of life; an 80-year-old in 2011, nine years.

Similar trends, though with lower numbers (so far), have occurred in every part of the world. For example, a 10-year-old Ethiopian in 1950 could expect to live to 44; a 10-year-old Ethiopian today can expect to live to 61. The economist Steven Radelet has pointed out that “the improvements in health among the global poor in the last few decades are so large and widespread that they rank among the greatest achievements in human history. Rarely has the basic well-being of so many people around the world improved so substantially, so quickly. Yet few people are even aware that it is happening.”¹³

And no, the extra years of life will not be spent senile in a rocking chair. Of course the longer you live, the more of those years you’ll live as an older person, with its inevitable aches and pains. But bodies that are better at resisting a mortal blow are also better at resisting the lesser assaults of disease, injury, and wear. As the life span is stretched, our run of vigor is stretched out as well, even if not by the same number of years. A heroic project called the Global Burden of Disease has tried to measure this improvement by tallying not just the number of people who drop dead of each of 291 diseases and disabilities, but how many years of healthy life they lose, weighted by the degree to which each condition compromises the quality of their lives. For the world in 1990, the project estimated that 56.8 of the 64.5 years of life that an average person could be expected to live were years of healthy life. And at least in developed countries, where estimates are available for 2010 as well, we know that out of the 4.7 years of additional expected life we gained in those two decades, 3.8 were healthy years.¹⁴ Numbers like these show that people today live far more years in the pink of health than their ancestors lived altogether, healthy and infirm years combined. For many people the greatest fear raised by the prospect of a longer life is dementia, but another pleasant surprise has come to light: between 2000 and 2012, the rate among Americans over 65 fell by a quarter, and the average age at diagnosis rose from 80.7 to 82.4 years.¹⁵

There is still more good news. The curves in figure 5-4 are not tapestries of your life that have been drawn out and measured by two of the Fates and will someday be cut by the third. Rather, they are projections from today’s vital statistics, based on the assumption that medical knowledge will be frozen at its current state. It’s not that anyone believes that assumption, but in the absence of clairvoyance about future medical advances we have no other choice. That means you will almost certainly live longer—perhaps much longer—than the numbers you read off the vertical axis.