There are important questions about the appropriate role of government in encouraging healthy behavior. As a free society we should have deep reservations about forcibly taking people’s money and using it to tell them how they should live, even when we are sure that would make for a better society. History is replete with examples of tyrannical majorities wasting resources and even fueling crime combating`harmful’ behavior. Thus we already have plenty of reason to tread carefully when legislation to discourage tobacco use, encourage exercise or promote a healthy diet is proposed. However, I have a much more fundamental question. Is it even preferable to have a society where people live longer?

At first glance this seems to be a truly stupid question. After all it’s bad when people die early. Isn’t it? Well, I certainly don’t want to die and neither do most people but that misses the point. We all die eventually and even if we personally want to put off death as long as possible can we truly say that a society where the average life span is 90 years rather than 70 is a better place? Would a society where the average life span was 200 years be even better? What sort of life span would be optimal?

It’s tempting to answer ‘infinite’ and certainly it would be wonderful if we could all retain our youth for forever and never have to grieve over lost friends and family. However, for the immediate future this simply isn’t possible. No healthy diet or prudent lifestyle can reduce the (average) number of friends we must mourn¹ and no amount of yoga or wheatgrass smoothies can prevent old age from taking it’s toll. Moreover, suppose we really could increase our lifespan indefinitely. At least for the next century or so we would have to virtually stop reproducing to avoid outgrowing our resources.

Ultimately we can’t simply say ‘life is good so we want more of it.’ Almost certainly such a policy would actually demand we divert money from healthcare into programs encouraging reproduction. As a society we’ve already reached the conclusion that it’s better to maintain a relatively small population that can live well than to expand into a great multitude that can barely make do. But rationally applying this insight to this question suggests that investing in longer life spans might not make sense.

Certainly we feel greater pain when someone is snatched from life too early and so we certainly shouldn’t stop pursuing more effective treatments to save people who might otherwise be struck down in the prime of life. Nor would we want to create distress or anger by denying people treatment. However, researching ways to further prolong our life span would likely introduce greater variability (some people die of heart attacks at 65 others make it to 130) and thus prolong the time people would have to endure the loss of loved ones as well as the sense of tragedy and anger at their deaths. Other things being equal a society is better if people spend a smaller proportion of their lives old and frail and since extending old age is unlikely to make people substantially happier (on average²) investing in technologies to lengthen our lifespan seems counterproductive. Of course we should look for technologies that let people be healthy and fit for a greater fraction of their lives and if we are able to make 80 feel like 55 that might justify more investment in keeping people alive till 80.

The observation that merely putting off death is not necessarily a desirable end in and of itself also has substantial consequences to what kind of charity and aid is best to give to the third world. However, that will have to wait for another post.