Peter Thiel discusses the potential future of life expectancy, highlighting the slow progress of innovation in this area. He predicts a straight line extrapolation of increased life expectancy, potentially reaching his early to mid-nineties. However, he acknowledges the variability and the possibility of significant advancements leading to much longer lifespans. Tyler Cowen adds that the gains in life expectancy have mainly come from younger individuals, casting doubt on the likelihood of many people reaching 100.