1) If the worldwide death rate drops by two-thirds (per the figure for age-related deaths referred to in the article) but there is no corresponding change in the worldwide birth rate (which Mr. de Grey doesn’t address), wouldn’t overpopulation actually become a genuine, and major, crisis (as opposed to the mere red herring it is now)?

2) Even without overpopulation, wouldn’t a civilization full of centuries- and millennia-old people, set in their ways and jaded beyond our current ability to fathom from their centuries/millenia of lifetime experience, eventually become terminally stagnant? There is something to be said for a new generation taking over and correcting the excesses and shortcomings of the old.

3) Last but not least, how would such long/indefinite lifespans, were they to become the norm, affect human attitudes toward death? Just to give the most obvious example, with hundreds or thousands of years of life ahead of them instead of merely a few decades, would people still be willing to take on dangerous jobs, such as law enforcement or even military service? And how would that impact society?