All good, my beef is with Kurzweil's unscientific intentional misuse of data.
"Longevity" is the term in the social sciences for average age at death for only people that die of old age. Kurzweil used that word, he said "In the eighteenth century, we added a few days every year to human longevity; during the nineteenth century we added a couple of weeks each year; and now we’re adding almost a half a year every year."
Life expectancy increased. Longevity did not. It's somewhat common to confuse them, so he could be forgiven for a mistake, except that it wasn't a mistake, he knows the difference, and his graph is evidence. That he included numbers from the 1920s and then skipped to 2000, is impossible to do accidentally, and if you include 1940-1990, you'd see lifespan flatlines. But then he'd have to admit neither life expectancy nor longevity are on exponential growth curves. They're not linear or even sublinear either. Longevity has always been flat, and lifespan has historical dips and bumps.
"Longevity" is the term in the social sciences for average age at death for only people that die of old age. Kurzweil used that word, he said "In the eighteenth century, we added a few days every year to human longevity; during the nineteenth century we added a couple of weeks each year; and now we’re adding almost a half a year every year."
Life expectancy increased. Longevity did not. It's somewhat common to confuse them, so he could be forgiven for a mistake, except that it wasn't a mistake, he knows the difference, and his graph is evidence. That he included numbers from the 1920s and then skipped to 2000, is impossible to do accidentally, and if you include 1940-1990, you'd see lifespan flatlines. But then he'd have to admit neither life expectancy nor longevity are on exponential growth curves. They're not linear or even sublinear either. Longevity has always been flat, and lifespan has historical dips and bumps.