is the ability to live forever,or put another way, it is an immunity from death. It is unknown whether human physical (material) 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. And even should human biological immortality be achieved, people could still continue to die from unforeseeable traumatic events.
In religious (typically Christian) contexts, immortality is often stated to be among the promises by God (or other deities) to human beings who show goodness or else follow divine law (cf. resurrection). Moreover, only God is regarded as truly immortal, hence it is only through God's resources for resurrection and salvation that human beings may transcend death and live eternally.
Certain scientists, futurists, and philosophers, have theorized about the immortality of the material human body, and 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 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.
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, or whether an immaterial soul exists and possesses immortality, has been a major point of focus of religion, as well as the subject of speculation, fantasy, and debate.
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."