Immortality is the ability to live
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...

 forever. It is unknown 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. Natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 has developed potential biological immortality
Biological immortality
Biological immortality refers to a stable rate of mortality as a function of chronological age. Some individual cells and entire organisms in some species achieve this state either throughout their existence or after living long enough. This requires that death occur from injury or disease rather...

 in at least one species, the jellyfish Turritopsis nutricula
Turritopsis nutricula
Turritopsis nutricula, the immortal jellyfish, is a hydrozoan whose medusa, or jellyfish, form can revert to the polyp stage after becoming sexually mature. It is the only known case of a metazoan capable of reverting completely to a sexually immature, colonial stage after having reached sexual...


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
Life extension
Life extension science, also known as anti-aging medicine, experimental gerontology, and biomedical gerontology, is the study of slowing down or reversing the processes of aging to extend both the maximum and average lifespan...

 is a more achievable goal in the short term, with immortality awaiting further research breakthroughs into an indefinite future.

A toy which people cry for,And on their knees apply for,Dispute, contend and lie for,And if allowedWould be right proudEternally to die for.

Ambrose Bierce, s:The_Devil%27s_Dictionary/I|The Devil's Dictionary. Reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895).

Immortality! We bow before the very term. Immortality! Before it reason staggers, calculation reclines her tired head, and imagination folds her weary pinions. Immortality! It throws open the portals of the vast forever; it puts the crown of deathless destiny upon every human brow; it cries to every uncrowned king of men, "Live forever, crowned for the empire of a deathless destiny!"

George Douglas, p. 337.

The soul secured in her existence, smilesAt the drawn dagger, and defies its point.The stars shall fade away, the sun himselfGrow dim with age, and nature sink in years,But thou shalt flourish in immortal youth,Unhurt amidst the war of elements,The wreck of matter, and the crash of worlds.

Joseph Addison, p. 337.

Earthly providence is a travesty of justice on any other theory than that it is a preliminary stage, which is to be followed by rectifications. Either there must be a future, or consummate injustice sits upon the throne of the universe. This is the verdict of humanity in all the ages.

Randolph Sinks Foster, p. 337.

Without a belief in personal immortality, religion surely is like an arch resting on one pillar, like a bridge ending in an abyss.

Max Muller, p. 337.

See truth, love, and mercy in triumph descending,And nature all glowing in Eden's first bloom!On the cold cheek of death smiles and roses are blending,And beauty immortal awakes from the tomb.

James Beattie, p. 338.

Tell me why the caged bird nutters against its prison bars, and I will tell you why the soul sickens of earthliness. The bird has wings, and wings were made to cleave the air, and soar in freedom in the sun. The soul is immortal — it cannot feed upon husks.

Randolph Sinks Foster, p. 338.

I feel that I was made to complete things. To accomplish only a mass of beginnings and attempts would be to make a total failure of life. Perfection is the heritage with which my Creator has endowed me, and since this short life does not give completeness, I must have immortal life in which to find it.

Randolph Sinks Foster, p. 338.

It is our souls which are the everlastingness of God's purpose in this earth.

William Mountford, p. 339.