1. There is no normal human life span, or if there is, it was very short.
Life-expectancy for the ancient Romans was about 23 years; today the average life-expectancy in the world is close to 64 years. For the past 150 years, best-performance life-expectancy has increased at a very steady rate of 3 months per year.
2. Aging is the biggest cause of death and misery in humanity.
Approximately 100,000 people die each day from age-related causes; about 150,000 people die each day in total. Cardiovascular disease (strongly age-related) is emerging as the biggest cause of death in the developing world.
3. Progress is possible
The goal should be to extend the healthy and productive lifespan, not to just keep people alive longer on respirators or in nursing homes. This is embodied in the concept not of life span but “health span.” The easiest way to do this is to prolong healthy life and not attempt to compress morbidity.
The authors state that the more we understand the biochemical processes involved in senescence the more we find that they look like disease processes:
The accumulation of lysosomal aggregates and amyloid plaques, extracellular protein-protein cross-linking, nuclear and mitochondrial mutations, cell atrophy, cell senescence, and cell loss without replacement: these processes may all be implicated in both pathology and senescence. At the level of genetics and biochemistry, there simply does not seem to be any meaningful distinction between "processes predisposing to or constituting disease" and "normal aging".Moreover, they argue that ethical objections to radical life extension can be addressed. "Of course extending healthy lifespan might create various problems and challenges," says Savulescu, "But for any possible problem that might arise, one question that we must not fail to ask ourselves is: 'Is this problem so bad that it is worth sacrificing up to 100,000 lives per day to avoid having to solve it?" If the answer is obviously no, then we should look for solutions.'"
The authors address two objections in particular:
1. Obligations to Future Generations
There is an argument out there which suggests we have an obligation to die and turn the world over to the next generation. How long each generation should live raises deep questions about intergenerational relations, quality of life and burden of care. However, there's no reason to believe that healthy and vibrant aged people can still be economically productive, self supporting and providers of knowledge, experience and care for younger generations. The answers are not clear, especially when life extension is coupled with life enhancement.
"At any rate," says Savulescu, "since few of us believe there is a positive moral obligation to have children, that is to create future people, the obligation to create new generations must be weak."
2. Loss of Meaning
There is little empirical evidence to support the suggestion that longer good lives lose meaning. Research shows that life satisfaction remains relatively stable into old age. One survey of 60,000 adults from 40 nations discovered a slight upward trend in life satisfaction from the 20s to the 80s in age. And with the advent of human enhancement– enhancement of cognitive powers, physical abilities and control of mood – this is likely to be even less of a problem.
The authors conclude by noting, "Our goal should be more, much more, longer and better life. We need a war on aging."