Jeanne Calment lived her entire life in the South of France. She filled her days with leisurely pursuits, enjoying a glass of port, a cigarette and some chocolate nearly every day. In 1997, Ms. Calment died. She was 122.\n\nWith medical and social advances mitigating diseases of old age and prolonging life, the number of exceptionally long-living people is increasing sharply. But no one is known to have matched, let alone surpassed, Ms. Calment\u2019s record.\n\nLongevity scientists hold a wide range of nuanced perspectives on the future of humanity. Some consider life span to be like a candle wick, burning for a limited time. While others view it as a supremely, maybe even infinitely elastic band.\n\nAs the eminent physicist Richard Feynman put it in a 1964 lecture, \u201cThere is nothing in biology yet found that indicates the inevitability of death.\u201d