Horizon - Life and Death in the 21st Century - Living Forever [2000-01-04]
Immortality (or eternal life) is the concept of living in a physical or spiritual form for an infinite or inconceivably vast length of time.
As immortality is the negation of mortalityâ€”not dying or not being subject to deathâ€”it has been a subject of fascination to humanity since at least the beginning of history. The Epic of Gilgamesh, one of the first literary works, dating back at least to the 22nd century BC, is primarily a quest of a hero seeking to become immortal. What form an unending human life would take (as well as whether it is subject to incapacitation), or whether the soul exists and possesses immortality, has been a major point of focus of religion, as well as the subject of speculation, fantasy, and debate.
It is not known whether human physical immortality is an achievable condition. Biological forms have inherent limitations which may or may not be able to be overcome through medical interventions or engineering. As of 2009, natural selection has developed biological immortality in at least one species, the jellyfish Turritopsis nutricula, one consequence of which is a worldwide population explosion of the organism.
Certain scientists, futurists, and philosophers, such as Ray Kurzweil, advocate that human immortality is achievable in the first few decades of the 21st century, while other advocates believe that life extension is a more achievable goal in the short term, with immortality awaiting further research breakthroughs further into an indefinite future. Aubrey de Grey, a researcher who has developed a series of biomedical rejuvenation strategies to reverse human aging (called SENS), believes that his proposed plan for ending aging may be implementable in two or three decades. The absence of aging would provide humans with biological immortality, but not invulnerability to death by physical trauma:
According to 2002 statistical data, the odds of an individual being traumatically killed are once in every 1,700 years.
Eternal life can also be defined as a timeless existence, which is also not known for certain to be achievable, or even definable, despite millennia of arguments for eternity. Wittgenstein, in a notably non-theological interpretation of eternal life, writes in the Tractatus that, "If we take eternity to mean not infinite temporal duration but timelessness, then eternal life belongs to those who live in the present."