Substantial life extension and quality of life

Caloric restriction mimetics (CRMs) are emerging biotechnologies that promise to substantially enhance human lifespan. CRMs like resveratrol, metformin and rapamycin have been extensively tested in animals and have undergone clinical trials in humans, with positive indications for extended lifespan. This raises important questions for individuals and society: Is it really better to have a longer life? Would life-extending biotechnologies contribute to social problems like overpopulation? Will CRMs increase the longevity gap between haves and havenots? Worryingly, many of these concerns are neglected, both in individual choices and in social policy. The imminent availability of interventions that substantially increase lifespan creates an urgent need for informed individual and policy decisions. As a step in this direction I focus on whether life extension by CRMs would make a person's life better. One of the greatest fears in this regard is that lifespan augmenting technologies would result in a prolonged old age, and an extended period spent in intolerably poor health. On the basis of empirical studies, I claim that CRMs will not result in worse health than is normally the case in old age. However, since they slow down the ageing process they will extend the period in which one is more susceptible to the diseases of old age. Though preferable to substantially worse health, prolonged old age may seem undesirable to some. I make the case that CRMs would most likely improve one's quality of life. This is because they would add to life's value by increasing the number of years spent in good health. Moreover, I argue that even years spent in worse health, above a certain level, can contribute to the goodness of life. These considerations mean that this emerging biotechnology is likely to increase both the quantity and quality of life, and should provide part of the basis for informed decisions about the individual consequences of extending lifespan using CRMs.