(The New Yorker) – On a recent afternoon, I chased my three-year-old daughter around the playground for an hour. When we returned home, she spread a jigsaw puzzle out on the floor and looked up expectantly. I liked the idea of sitting still, but my knees hurt and my back was tense. I had to transfer the puzzle to a grownup table and sit my daughter in a booster seat. She didn’t seem to mind, but I remember that day as the first time that my physical limits noticeably constrained what we could do together. Longevity has become a concrete problem, just as it was for my grandparents: I wake up with aches in long-ignored joints and tendons; I calculate, with dismay, the age I’ll be when my children graduate from college or start their own families. One day, we’re going to die. What should that mean for how we live today? (Read More)