I just wanted to amplify on a point we discussed regarding the concept of human longevity. This has two distinct facets:
The first (Life Extension, or Longevity) concerns the natural developmental process, bound by evolutionary constraints which limit the maximum human lifespan to around 120 years. In this case, the survival of the species is ensured through germ-line immortality (the immortality of out genetic material) associated with a perpetual cycle of bodily birth, development and death, and an absolute limit on maximum lifespan. Within this scenario, it is possible to employ strategies and interventions such as nutrients, supplements, antioxidants, cell repair therapies, telomerase, stem cells, genetic manipulation of relevant genes such as TOR, Foxo, Sir etc., as well as other SENS-type rejuvenation techniques (see
www.sens.org).
The second (Radical Life Extension, or Radical Longevity) is encountered beyond the intrinsic barrier that limits human maximum lifespan. It is possible that, individuals who have managed to break through this barrier (which is currently 122 years) will be subjected to natural evolutionary pressures that facilitate indefinite lifespan. An indefinite lifespan is a lifespan that is not subjected to the effects of age, in other words the mortality rate as a function of age is virtually zero. Here, interventions based on tablets or injections directed at the individual alone will have a trivial impact on the length of life. It would be necessary to devise strategies which encompass the society and the planet within a framework of mutual/reciprocal co-operation. A highly sophisticated, complex approach will be needed in order to maintain a perpetual correction of age-related damage, leading to radical life extension. This is described by the ELPIs concept (see
www.elpistheory.info).