Opponents of engineered longevity often put forward a false choice between quality of life and length of life. But medicine of the future will give us both: "one of the ten most-read articles on the BBC news website at the moment is a piece by Joan Bakewell suggesting that greater longevity may not be desirable. It's a superficially thoughtful commentary, but in truth it just runs through a series of standard knee-jerk reactions, most of which don't stand up to much scrutiny. Firstly, there is the implicit assumption that any extra years of life are bound to be of extremely low quality, due to physical and mental frailty. But one thing that actually unites almost all scientists in this area - from the mainstream ones like S Jay Olshansky who seek to slow the aging process by a few years, to the 'heretics' like [Aubrey] de Grey who seek to conquer it entirely - is that they don't think an increased lifespan would be beneficial unless 'healthspan' is boosted to an equivalent (or more likely greater) degree. There's always the danger of unintended consequences, of course, but there's no reason to fear the stated goal of the research. ... Finally, there's the general sense in Bakewell's article that 'a fuller life is better than a longer one'. This is a superficially attractive philosophy, but once again, it looks somewhat different if you just tweak the implicit parameters a little. What if the 'fuller life' lasted a mere twenty years, and the 'longer life' lasted eighty? Would anyone seriously suggest that the fullness of the twenty years entirely makes up for the tragedy of the lost sixty years? Some might, but it would be a far tougher case to make, simply because of our perceptions of what a 'natural' lifespan is. And yet the span we fetishise as being optimal is just a random quirk of the stage of evolution we happen to be at - some species live much shorter lives than we do, other species much longer."