“IN THE long run,” as John Maynard Keynes observed, “we are all dead.” True. But can the short run be elongated in a way that makes the long run longer? And if so, how, and at what cost? People have dreamt of immortality since time immemorial. They have sought it since the first alchemist put an elixir of life on the same shopping list as a way to turn lead into gold. They have written about it in fiction, from Rider Haggard’s “She” to Frank Herbert’s “Dune”. And now, with the growth of biological knowledge that has marked the past few decades, a few researchers believe it might be within reach.
To think about the question, it is important to understand why organisms—people included—age in the first place. People are like machines: they wear out. That much is obvious. However a machine can always be repaired. A good mechanic with a stock of spare parts can keep it going indefinitely. Eventually, no part of the original may remain, but it still carries on, like Lincoln’s famous axe that had had three new handles and two new blades.
