Too many discussions of radical life extension veer off into the immortality trap - at which point things degenerate into hair splitting and angels dancing on the head of a pin. Talking about immortality has little relevance to the practical objective of reversing degenerative aging in humans. Over at Depressed Metabolism you'll find an example of how this tends to progress, followed by these thoughts: "Although speculation about how immortality may affect human psychology can be intriguing, our limited knowledge about the universe and lack of empirical observations of actual immortals make this a highly speculative affair, leaving much room for injecting personal feelings and wishful thinking. ... Few philosophers against immortality argue that today's lifespan is too long. Which again raises the question, how long is too long? Ultimately, such an answer can only be answered empirically by the individuals who will live a much longer lifespan than those living today." It comes back to practical concerns in the end: I, for one, am in favor of getting the job done first and pontificating later, when there is all the time in the world to do so.

Link: http://www.depressedmetabolism.com/2008/10/22/the-secular-case-against-immortality/