Over the next few decades, advances in biotechnology and nanotechnology will give us novel and effective therapies for radical human life extension. For the past century or so, human life expectancy has been increasing by an average of a quarter of a year per year, and this trend is all but certain to accelerate in the future. There is tremendous financial backing for technology that provably extends human life or improves its quality. With the inevitability of better anti-aging technology, bioconservatives and life extension advocates alike have begun to examine the potential issues rising from longer and healthier lifespans. Of course, the most frequently heard objection in discussions of life extension is overpopulation.
Before going into the objections, note this: Given enough resources, humans reproduce exponentially. That is, the population doubles every given time interval. Currently this interval is about 34 years.
The amount of resources we can accumulate is bounded by three dimensions - which means our resource growth is at best a cubic function. If you plot an exponential function versus a cubic function on a graph, you will see that exponentials always overwhelm such functions given enough time. The moral of the story is that, even with short lifespans, organisms are simply designed to reproduce quickly and consume all local resources faster than new resources can be acquired. This means that with or without life extension, the birth rate has to be kept low enough that resources do not run out before we can acquire more.
People such as Leon Kass and Bill McKibben have argued that radical life extension would eliminate the point of living. The finitude of life is supposed to give it meaning and a clear beginning, middle, and end. It maintains the necessary social roles of the young, the middle-aged, and the elderly. On the BBC, a commentator even went so far as to say that extreme life extension would ruin Christmas.
Overpopulation is a widespread concern. Environmentalists especially worry about the human footprint on our fragile biosphere. Life extension advocates point to declining birth rates worldwide, noting that as women are better educated and manual labor becomes less important, parents focus on quality over quantity. They remark that we will inevitably need to transition to a world in which we reproduce responsibly, and only have as many children as the societal infrastructure can support. Improvements in technology would also allow us to better exploit limited resources and support our expansion into space.
The bioconservatives and environmentalists are not so optimistic. They see renewable energy and popular space travel as far-future advancements, solutions that will not arrive until it is too late. Some even argue that the "resource wars" have already begun and we are irreversibly headed towards a Malthusian catastrophe.
Another common objection is that as immortals, we would get bored. Of course, there are many people who object to this, citing hundreds or even thousands years worth of experiences they would like to have, given the opportunity. Some transhumanists see intelligence enhancement as the solution to boredom. They say that if we were smarter, we could support a wider, more complex variety of thoughts and observations that would sustain our interest almost indefinitely.
