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Immortality is the concept of eternal life. Some modern species may possess
biological immortality Biological immortality (sometimes referred to as bio-indefinite mortality) is a state in which the rate of mortality from senescence is stable or decreasing, thus decoupling it from chronological age. Various unicellular and multicellular species, ...
. Some scientists, futurists, and philosophers have theorized about the immortality of the human body, with some suggesting that human immortality may be achievable in the first few decades of the 21st century with the help of certain technologies such as
mind uploading Mind uploading is a speculative process of whole brain emulation in which a brain scan is used to completely emulate the mental state of the individual in a digital computer. The computer would then run a simulation of the brain's information pr ...
(
digital immortality Digital immortality (or "virtual immortality") is the hypothetical concept of storing (or transferring) a person's personality in digital substrate, i.e., a computer, robot or cyberspace (mind uploading). The result might look like an avatar beha ...
). Other advocates believe that life extension is a more achievable goal in the short term, with immortality awaiting further research breakthroughs. The absence of aging would provide humans with biological immortality, but not invulnerability to death by disease or injury. Whether the process of internal immortality is delivered within the upcoming years depends chiefly on research (and in neuron research in the case of internal immortality through an immortalized cell line) in the former view and perhaps is an awaited goal in the latter case. What form an unending human life would take, or whether an immaterial
soul In many religious and philosophical traditions, there is a belief that a soul is "the immaterial aspect or essence of a human being". Etymology The Modern English noun '' soul'' is derived from Old English ''sāwol, sāwel''. The earliest att ...
exists and possesses immortality, has been a major point of focus of religion, as well as the subject of speculation and debate. In religious contexts, immortality is often stated to be one of the promises of divinities to human beings who perform
virtue Virtue ( la, virtus) is morality, moral excellence. A virtue is a trait or quality that is deemed to be morally good and thus is Value (ethics), valued as a foundation of principle and good moral being. In other words, it is a behavior that sh ...
or follow divine law.


Definitions


Scientific

Life extension technologies promise a path to complete rejuvenation.
Cryonics Cryonics (from el, κρύος ''kryos'' meaning 'cold') is the low-temperature freezing (usually at ) and storage of human remains, with the speculative hope that resurrection may be possible in the future. Cryonics is regarded with skeptic ...
holds out the hope that the dead can be revived in the future, following sufficient medical advancements. While, as shown with creatures such as hydra and Planarian worms, it is indeed possible for a creature to be
biologically immortal Biological immortality (sometimes referred to as bio-indefinite mortality) is a state in which the rate of mortality from senescence is stable or decreasing, thus decoupling it from chronological age. Various unicellular and multicellular species, ...
, it is not known if it will be possible for humans in the near-future.


Religious

Immortality in religion refers usually to either the belief in physical immortality or a more spiritual '' afterlife''. In traditions such as ancient Egyptian beliefs, Mesopotamian beliefs and ancient Greek beliefs, the immortal gods consequently were considered to have physical bodies. In Mesopotamian and Greek religion, the gods also made certain men and women physically immortal, whereas in Christianity, many believe that all true believers will be resurrected to physical immortality. Similar beliefs that physical immortality is possible are held by Rastafarians or Rebirthers.


Physical immortality

Physical immortality is a state of life that allows a person to avoid death and maintain conscious thought. It can mean the unending existence of a person from a physical source other than organic life, such as a computer. Pursuit of physical immortality before the advent of modern science included
alchemists Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim ...
seeking to create the Philosopher's Stone,Theophrastus Paracelsus. ''The Book of the Revelation of Hermes''. 16th century and various cultures' legends such as the Fountain of Youth or the
Peaches of Immortality In Chinese mythology, Peaches of Immortality ( or ) are consumed by the immortals due to their mystic virtue of conferring longevity on all who eat them. Peaches symbolizing immortality (or the wish for a long and healthy life) are a common symbo ...
inspiring attempts at discovering elixirs of life. Modern scientific trends, such as
cryonics Cryonics (from el, κρύος ''kryos'' meaning 'cold') is the low-temperature freezing (usually at ) and storage of human remains, with the speculative hope that resurrection may be possible in the future. Cryonics is regarded with skeptic ...
,
digital immortality Digital immortality (or "virtual immortality") is the hypothetical concept of storing (or transferring) a person's personality in digital substrate, i.e., a computer, robot or cyberspace (mind uploading). The result might look like an avatar beha ...
, breakthroughs in rejuvenation, or predictions of an impending technological singularity, to achieve genuine human physical immortality, must still overcome all causes of death to succeed:


Causes of death

There are three main causes of death: aging,
disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
, and injury Such issues can be resolved with the solutions provided in research to any end providing such alternate theories at present that require unification.


Aging

Aubrey de Grey Aubrey David Nicholas Jasper de Grey (; born 20 April 1963) is an English author and biomedical gerontologist. He is the author of ''The Mitochondrial Free Radical Theory of Aging'' (1999) and co-author of ''Ending Aging'' (2007). He is known ...
, a leading researcher in the field, defines aging as "a collection of cumulative changes to the molecular and cellular structure of an adult
organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells ( cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fu ...
, which result in essential metabolic processes, but which also, once they progress far enough, increasingly disrupt metabolism, resulting in
pathology Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...
and death." The current causes of aging in humans are cell loss (without replacement),
DNA damage DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA d ...
,
oncogenic Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnor ...
nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...
mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, m ...
s and epimutations, cell senescence, mitochondrial mutations, lysosomal aggregates, extracellular aggregates, random extracellular cross-linking,
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
decline, and endocrine changes. Eliminating aging would require finding a solution to each of these causes, a program de Grey calls engineered negligible senescence. There is also a huge body of knowledge indicating that change is characterized by the loss of molecular fidelity.


Disease

Disease is theoretically surmountable by technology. In short, it is an abnormal condition affecting the body of an organism, something the body shouldn't typically have to deal with its natural make up. Human understanding of
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar work ...
is leading to cures and treatments for a myriad of previously incurable diseases. The mechanisms by which other diseases do damage are becoming better understood. Sophisticated methods of detecting diseases early are being developed.
Preventative medicine Preventive healthcare, or prophylaxis, consists of measures taken for the purposes of disease prevention.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental hea ...
is becoming better understood. Neurodegenerative diseases like
Parkinson's Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
and
Alzheimer's Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As t ...
may soon be curable with the use of stem cells. Breakthroughs in cell biology and telomere research are leading to treatments for cancer. Vaccines are being researched for AIDS and
tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, ...
. Genes associated with
type 1 diabetes Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that originates when cells that make insulin (beta cells) are destroyed by the immune system. Insulin is a hormone required for the cells to use blood sugar f ...
and certain types of cancer have been discovered, allowing for new therapies to be developed. Artificial devices attached directly to the
nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...
may restore sight to the blind. Drugs are being developed to treat a myriad of other diseases and ailments.


Trauma

Physical trauma would remain as a threat to perpetual physical life, as an otherwise immortal person would still be subject to unforeseen accidents or catastrophes. The speed and quality of
paramedic A paramedic is a registered healthcare professional who works autonomously across a range of health and care settings and may specialise in clinical practice, as well as in education, leadership, and research. Not all ambulance personnel are p ...
response remains a determining factor in surviving severe trauma. A body that could automatically repair itself from severe trauma, such as speculated uses for nanotechnology, would mitigate this factor. The brain cannot be risked to trauma if a continuous physical life is to be maintained. This aversion to trauma risk to the brain would naturally result in significant behavioral changes that would render physical immortality undesirable for some people.


Environmental change

Organisms otherwise unaffected by these causes of death would still face the problem of obtaining sustenance (whether from currently available agricultural processes or from hypothetical future technological processes) in the face of changing availability of suitable resources as environmental conditions change. After avoiding aging, disease, and trauma, death through resource limitation is still possible, such as hypoxia or
starvation Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism's life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, de ...
. If there is no limitation on the degree of gradual mitigation of risk then it is possible that the
cumulative probability In probability theory and statistics, the cumulative distribution function (CDF) of a real-valued random variable X, or just distribution function of X, evaluated at x, is the probability that X will take a value less than or equal to x. E ...
of death over an infinite horizon is less than certainty, even when the risk of fatal trauma in any finite period is greater than zero. Mathematically, this is an aspect of achieving ‘actuarial escape velocity’.


Biological immortality

Biological immortality is an absence of aging. Specifically it is the absence of a sustained increase in rate of mortality as a function of chronological age. A cell or organism that does not experience aging, or ceases to age at some point, is biologically immortal.
Biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize ...
s have chosen the word "immortal" to designate cells that are not limited by the Hayflick limit, where cells no longer divide because of
DNA damage DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA d ...
or shortened telomeres. The first and still most widely used immortal cell line is HeLa, developed from cells taken from the malignant cervical tumor of Henrietta Lacks without her consent in 1951. Prior to the 1961 work of
Leonard Hayflick Leonard Hayflick (born 20 May 1928) is a Professor of Anatomy at the UCSF School of Medicine, and was Professor of Medical Microbiology at Stanford University School of Medicine. He is a past president of the Gerontological Society of America and ...
, there was the erroneous belief fostered by Alexis Carrel that all normal somatic cells are immortal. By preventing cells from reaching senescence one can achieve biological immortality; telomeres, a "cap" at the end of DNA, are thought to be the cause of cell aging. Every time a cell divides the telomere becomes a bit shorter; when it is finally worn down, the cell is unable to split and dies. Telomerase is an enzyme which rebuilds the telomeres in stem cells and cancer cells, allowing them to replicate an infinite number of times. No definitive work has yet demonstrated that telomerase can be used in human somatic cells to prevent healthy tissues from aging. On the other hand, scientists hope to be able to grow organs with the help of stem cells, allowing organ transplants without the risk of rejection, another step in extending human life expectancy. These technologies are the subject of ongoing research, and are not yet realized.


Biologically immortal species

Life defined as biologically immortal is still susceptible to causes of death besides aging, including disease and trauma, as defined above. Notable immortal species include: * ''Bacteria'' – Bacteria reproduce through binary fission. A parent bacterium splits itself into two identical daughter cells which eventually then split themselves in half. This process repeats, thus making the bacterium essentially immortal. A 2005 PLoS Biology paper suggests that after each division the daughter cells can be identified as the older and the younger, and the older is slightly smaller, weaker, and more likely to die than the younger. * '' Turritopsis dohrnii'', a jellyfish (phylum
Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that ...
, class Hydrozoa, order Anthoathecata), after becoming a sexually mature adult, can transform itself back into a polyp using the cell conversion process of transdifferentiation. ''Turritopsis dohrnii'' repeats this cycle, meaning that it may have an
indefinite lifespan Life extension is the concept of extending the human lifespan, either modestly through improvements in medicine or dramatically by increasing the maximum lifespan beyond its generally-settled limit of 125 years. Several researchers in the are ...
. Its immortal adaptation has allowed it to spread from its original habitat in the Caribbean to "all over the world". * '' Hydra'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
belonging to the phylum
Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that ...
, the class Hydrozoa and the order Anthomedusae. They are simple fresh-water predatory animals possessing radial symmetry. * '' Bristlecone pines'' are speculated to be potentially immortal; the oldest known living specimen is over 5,000 years old.


Evolution of aging

As the existence of biologically immortal species demonstrates, there is no
thermodynamic Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of ...
necessity for senescence: a defining feature of life is that it takes in free energy from the environment and unloads its
entropy Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodyna ...
as waste. Living systems can even build themselves up from seed, and routinely repair themselves. Aging is therefore presumed to be a byproduct of
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
, but why mortality should be selected for remains a subject of research and debate. Programmed cell death and the telomere "end replication problem" are found even in the earliest and simplest of organisms. This may be a tradeoff between selecting for cancer and selecting for aging. Modern theories on the evolution of aging include the following: * Mutation accumulation is a theory formulated by Peter Medawar in 1952 to explain how evolution would select for aging. Essentially, aging is never selected against, as organisms have offspring before the mortal mutations surface in an individual. *
Antagonistic pleiotropy The antagonistic pleiotropy hypothesis was first proposed by George C. Williams in 1957 as an evolutionary explanation for senescence. Pleiotropy is the phenomenon where one gene controls for more than one phenotypic trait in an organism. Antagoni ...
is a theory proposed as an alternative by George C. Williams, a critic of Medawar, in 1957. In antagonistic pleiotropy, genes carry effects that are both beneficial and detrimental. In essence this refers to genes that offer benefits early in life, but exact a cost later on, i.e. decline and death. * The disposable soma theory was proposed in 1977 by Thomas Kirkwood, which states that an individual body must allocate energy for metabolism, reproduction, and maintenance, and must compromise when there is food scarcity. Compromise in allocating energy to the repair function is what causes the body gradually to deteriorate with age, according to Kirkwood.


Immortality of the germ line

Individual organisms ordinarily age and die, while the germlines which connect successive generations are potentially immortal. The basis for this difference is a fundamental problem in biology. The Russian biologist and historian
Zhores A. Medvedev Zhores Aleksandrovich Medvedev (russian: Жоре́с Алекса́ндрович Медве́дев; 14 November 1925 – 15 November 2018) was a Russian agronomist, biologist, historian and dissident. His twin brother is the historian Roy Med ...
considered that the accuracy of
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...
replicative and other synthetic systems alone cannot explain the immortality of germ lines. Rather Medvedev thought that known features of the biochemistry and genetics of
sexual reproduction Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote th ...
indicate the presence of unique information maintenance and restoration processes at the different stages of gametogenesis. In particular, Medvedev considered that the most important opportunities for information maintenance of
germ cell Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embr ...
s are created by recombination during meiosis and
DNA repair DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA d ...
; he saw these as processes within the germ cells that were capable of restoring the integrity of DNA and
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s from the types of damage that cause irreversible aging in somatic cells.


Prospects for human biological immortality


Life-extending substances

Some scientists believe that boosting the amount or proportion of telomerase in the body, a naturally forming enzyme that helps maintain the protective caps at the ends of
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s, could prevent cells from dying and so may ultimately lead to extended, healthier lifespans. A team of researchers at the Spanish National Cancer Centre (
Madrid Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and ...
) tested the hypothesis on mice. It was found that those mice which were " genetically engineered to produce 10 times the normal levels of telomerase lived 50% longer than normal mice". In normal circumstances, without the presence of telomerase, if a cell divides repeatedly, at some point all the progeny will reach their Hayflick limit. With the presence of telomerase, each dividing cell can replace the lost bit of DNA, and any single cell can then divide unbounded. While this unbounded growth property has excited many researchers, caution is warranted in exploiting this property, as exactly this same unbounded growth is a crucial step in enabling cancerous growth. If an organism can replicate its body cells faster, then it would theoretically stop aging. Embryonic stem cells express telomerase, which allows them to divide repeatedly and form the individual. In adults, telomerase is highly expressed in cells that need to divide regularly (e.g., in the immune system), whereas most somatic cells express it only at very low levels in a cell-cycle dependent manner.


Technological immortality, biological machines, and "swallowing the doctor"

Technological immortality is the prospect for much longer life spans made possible by scientific advances in a variety of fields: nanotechnology, emergency room procedures, genetics, biological engineering, regenerative medicine, microbiology, and others. Contemporary life spans in the advanced industrial societies are already markedly longer than those of the past because of better nutrition, availability of health care, standard of living and bio-medical scientific advances. Technological immortality predicts further progress for the same reasons over the near term. An important aspect of current scientific thinking about immortality is that some combination of
human cloning Human cloning is the creation of a genetically identical copy (or clone) of a human. The term is generally used to refer to artificial human cloning, which is the reproduction of human cells and tissue. It does not refer to the natural concept ...
, cryonics or nanotechnology will play an essential role in extreme life extension. Robert Freitas, a nanorobotics theorist, suggests tiny medical nanorobots could be created to go through human bloodstreams, find dangerous things like cancer cells and bacteria, and destroy them. Freitas anticipates that gene-therapies and nanotechnology will eventually make the human body effectively self-sustainable and capable of living indefinitely in empty space, short of severe brain trauma. This supports the theory that we will be able to continually create biological or synthetic replacement parts to replace damaged or dying ones. Future advances in nanomedicine could give rise to life extension through the repair of many processes thought to be responsible for aging.
K. Eric Drexler Kim Eric Drexler (born April 25, 1955) is an American engineer best known for studies of the potential of molecular nanotechnology (MNT), from the 1970s and 1980s. His 1991 doctoral thesis at Massachusetts Institute of Technology was revised and ...
, one of the founders of nanotechnology, postulated cell repair devices, including ones operating within cells and using as yet hypothetical biological machines, in his 1986 book Engines of Creation. Raymond Kurzweil, a futurist and transhumanist, stated in his book '' The Singularity Is Near'' that he believes that advanced medical nanorobotics could completely remedy the effects of aging by 2030. According to Richard Feynman, it was his former graduate student and collaborator Albert Hibbs who originally suggested to him (circa 1959) the idea of a ''medical'' use for Feynman's theoretical micromachines (see biological machine). Hibbs suggested that certain repair machines might one day be reduced in size to the point that it would, in theory, be possible to (as Feynman put it) "swallow the doctor". The idea was incorporated into Feynman's 1959 essay '' There's Plenty of Room at the Bottom.''


Cryonics

Cryonics Cryonics (from el, κρύος ''kryos'' meaning 'cold') is the low-temperature freezing (usually at ) and storage of human remains, with the speculative hope that resurrection may be possible in the future. Cryonics is regarded with skeptic ...
, the practice of preserving organisms (either intact specimens or only their brains) for possible future revival by storing them at cryogenic temperatures where metabolism and decay are almost completely stopped, can be used to 'pause' for those who believe that life extension technologies will not develop sufficiently within their lifetime. Ideally, cryonics would allow clinically dead people to be brought back in the future after cures to the patients' diseases have been discovered and aging is reversible. Modern cryonics procedures use a process called vitrification which creates a glass-like state rather than
freezing Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid ...
as the body is brought to low temperatures. This process reduces the risk of ice crystals damaging the cell-structure, which would be especially detrimental to cell structures in the brain, as their minute adjustment evokes the individual's mind.


Mind-to-computer uploading

One idea that has been advanced involves uploading an individual's habits and memories via direct mind-computer interface. The individual's memory may be loaded to a computer or to a new organic body. Extropian
futurists Futurists (also known as futurologists, prospectivists, foresight practitioners and horizon scanners) are people whose specialty or interest is futurology or the attempt to systematically explore predictions and possibilities abou ...
like Moravec and Kurzweil have proposed that, thanks to exponentially growing computing power, it will someday be possible to upload human consciousness onto a computer system, and exist indefinitely in a virtual environment. This could be accomplished via advanced cybernetics, where computer hardware would initially be installed in the brain to help sort memory or accelerate thought processes. Components would be added gradually until the person's entire brain functions were handled by artificial devices, avoiding sharp transitions that would lead to issues of
identity Identity may refer to: * Identity document * Identity (philosophy) * Identity (social science) * Identity (mathematics) Arts and entertainment Film and television * ''Identity'' (1987 film), an Iranian film * ''Identity'' (2003 film), an ...
, thus running the risk of the person to be declared dead and thus not be a legitimate owner of his or her property. After this point, the human body could be treated as an optional accessory and the program implementing the person could be transferred to any sufficiently powerful computer. Another possible mechanism for mind upload is to perform a detailed scan of an individual's original, organic brain and simulate the entire structure in a computer. What level of detail such scans and simulations would need to achieve to emulate awareness, and whether the scanning process would destroy the brain, is still to be determined. It is suggested that achieving immortality through this mechanism would require specific consideration to be given to the role of
consciousness Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
in the functions of the mind. An uploaded mind would only be a copy of the original mind, and not the conscious mind of the living entity associated in such a transfer. Without a simultaneous upload of consciousness, the original living entity remains mortal, thus not achieving true immortality. Research on neural correlates of consciousness is yet inconclusive on this issue. Whatever the route to mind upload, persons in this state could then be considered essentially immortal, short of loss or traumatic destruction of the machines that maintained them.


Cybernetics

Transforming a human into a cyborg can include brain implants or extracting a human processing unit and placing it in a robotic life-support system. Even replacing biological organs with robotic ones could increase life span (e.g. pace makers) and depending on the definition, many technological upgrades to the body, like genetic modifications or the addition of nanobots would qualify an individual as a cyborg. Some people believe that such modifications would make one impervious to aging and disease and theoretically immortal unless killed or destroyed.


Digital immortality


Religious views

As late as 1952, the editorial staff of the '' Syntopicon'' found in their compilation of the Great Books of the Western World, that "The philosophical issue concerning immortality cannot be separated from issues concerning the existence and nature of man's soul." Thus, the vast majority of speculation on immortality before the 21st century was regarding the nature of the afterlife.


Ancient Greek religion

Immortality in ancient Greek religion originally always included an eternal union of body and soul as can be seen in
Homer Homer (; grc, Ὅμηρος , ''Hómēros'') (born ) was a Greek poet who is credited as the author of the ''Iliad'' and the ''Odyssey'', two epic poems that are foundational works of ancient Greek literature. Homer is considered one of the ...
,
Hesiod Hesiod (; grc-gre, Ἡσίοδος ''Hēsíodos'') was an ancient Greek poet generally thought to have been active between 750 and 650 BC, around the same time as Homer. He is generally regarded by western authors as 'the first written poet i ...
, and various other ancient texts. The soul was considered to have an eternal existence in Hades, but without the body the soul was considered dead. Although almost everybody had nothing to look forward to but an eternal existence as a disembodied dead soul, a number of men and women were considered to have gained physical immortality and been brought to live forever in either Elysium, the Islands of the Blessed, heaven, the ocean or literally right under the ground. Among those humans made immortal were
Amphiaraus In Greek mythology, Amphiaraus or Amphiaraos (; Ancient Greek: Ἀμφιάραος, Ἀμφιάρεως, "very sacred") was the son of Oicles, a seer, and one of the leaders of the Seven against Thebes. Amphiaraus at first refused to go with A ...
, Ganymede, Ino, Iphigenia,
Menelaus In Greek mythology, Menelaus (; grc-gre, Μενέλαος , 'wrath of the people', ) was a king of Mycenaean (pre- Dorian) Sparta. According to the ''Iliad'', Menelaus was a central figure in the Trojan War, leading the Spartan contingent of ...
,
Peleus In Greek mythology, Peleus (; Ancient Greek: Πηλεύς ''Pēleus'') was a hero, king of Phthia, husband of Thetis and the father of their son Achilles. This myth was already known to the hearers of Homer in the late 8th century BC. Bi ...
, and a great number of those who fought in the Trojan and Theban wars. Some were considered to have died and been resurrected before they achieved physical immortality.
Asclepius Asclepius (; grc-gre, Ἀσκληπιός ''Asklēpiós'' ; la, Aesculapius) is a hero and god of medicine in ancient Greek religion and mythology. He is the son of Apollo and Coronis, or Arsinoe, or of Apollo alone. Asclepius represen ...
was killed by Zeus only to be resurrected and transformed into a major deity. In some versions of the
Trojan War In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans ( Greeks) after Paris of Troy took Helen from her husband Menelaus, king of Sparta. The war is one of the most important events in Greek mythology and ...
myth,
Achilles In Greek mythology, Achilles ( ) or Achilleus ( grc-gre, Ἀχιλλεύς) was a hero of the Trojan War, the greatest of all the Greek warriors, and the central character of Homer's '' Iliad''. He was the son of the Nereid Thetis and Pe ...
, after being killed, was snatched from his funeral pyre by his divine mother Thetis, resurrected, and brought to an immortal existence in either Leuce, the Elysian plains, or the Islands of the Blessed.
Memnon In Greek mythology, Memnon (; Ancient Greek: Μέμνων means 'resolute') was a king of Aethiopia and son of Tithonus and Eos. As a warrior he was considered to be almost Achilles' equal in skill. During the Trojan War, he brought an army ...
, who was killed by Achilles, seems to have received a similar fate.
Alcmene In Greek mythology, Alcmene () or Alcmena (; Ancient Greek: Ἀλκμήνη or Doric Greek: Ἀλκμάνα, Latin: Alcumena means "strong in wrath") was the wife of Amphitryon by whom she bore two children, Iphicles and Laonome. She is best ...
, Castor,
Heracles Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon.By his adoptiv ...
, and Melicertes were also among the figures sometimes considered to have been resurrected to physical immortality. According to Herodotus' Histories, the 7th century BCE sage Aristeas of Proconnesus was first found dead, after which his body disappeared from a locked room. Later he was found not only to have been resurrected but to have gained immortality. The parallel between these traditional beliefs and the later resurrection of Jesus was not lost on early Christians, as
Justin Martyr Justin Martyr ( el, Ἰουστῖνος ὁ μάρτυς, Ioustinos ho martys; c. AD 100 – c. AD 165), also known as Justin the Philosopher, was an early Christian apologist and philosopher. Most of his works are lost, but two apologies and ...
argued: : "when we say ... Jesus Christ, our teacher, was crucified and died, and rose again, and ascended into heaven, we propose nothing different from what you believe regarding those whom you consider sons of Zeus." The philosophical idea of an immortal soul was a belief first appearing with either Pherecydes or the Orphics, and most importantly advocated by
Plato Plato ( ; grc-gre, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
and his followers. This, however, never became the general norm in Hellenistic thought. As may be witnessed even into the Christian era, not least by the complaints of various philosophers over popular beliefs, many or perhaps most traditional Greeks maintained the conviction that certain individuals were resurrected from the dead and made physically immortal and that others could only look forward to an existence as disembodied and dead, though everlasting, souls.


Buddhism

One of the three marks of existence in Buddhism is anattā, "non-self". This teaching states that the body does not have an eternal soul but is composed of five skandhas or aggregates. Additionally, another mark of existence is impermanence, also called anicca, which runs directly counter to concepts of immortality or permanence. According to one Tibetan Buddhist teaching, Dzogchen, individuals can transform the physical body into an immortal body of light called the rainbow body.


Christianity

Christian theology holds that Adam and Eve lost physical immortality for themselves and all their descendants in the Fall of man, although this initial "imperishability of the bodily frame of man" was "a preternatural condition". Christians who profess the Nicene Creed believe that every dead person (whether they believed in Christ or not) will be resurrected from the dead at the
Second Coming The Second Coming (sometimes called the Second Advent or the Parousia) is a Christian (as well as Islamic and Baha'i) belief that Jesus will return again after his ascension to heaven about two thousand years ago. The idea is based on messia ...
, and this belief is known as
Universal resurrection General resurrection or universal resurrection is the belief in a resurrection of the dead, or resurrection from the dead ( Koine: , ''anastasis onnekron''; literally: "standing up again of the dead") by which most or all people who have died ...
. While Paul the Apostle insisted that the resurrected body was only "spiritual" and that "flesh and blood cannot inherit the kingdom of God"., the Gospels increasingly emphasized the physical nature of the resurrection body – as the resurrected Jesus in the
Gospel of Luke The Gospel of Luke), or simply Luke (which is also its most common form of abbreviation). tells of the origins, Nativity of Jesus, birth, Ministry of Jesus, ministry, Crucifixion of Jesus, death, Resurrection of Jesus, resurrection, and Ascensi ...
insisting on his still consisting of "flesh and bones". This shift may have been in response to traditional Greek expectations that immortality always included both body and soul. N.T. Wright, a theologian and former
Bishop of Durham The Bishop of Durham is the Anglican bishop responsible for the Diocese of Durham in the Province of York. The diocese is one of the oldest in England and its bishop is a member of the House of Lords. Paul Butler has been the Bishop of Durham ...
, has said many people forget the physical aspect of what Jesus promised. He told
Time Time is the continued sequence of existence and event (philosophy), events that occurs in an apparently irreversible process, irreversible succession from the past, through the present, into the future. It is a component quantity of various me ...
: "Jesus' resurrection marks the beginning of a restoration that he will complete upon his return. Part of this will be the resurrection of all the dead, who will 'awake', be embodied and participate in the renewal. Wright says John Polkinghorne, a physicist and a priest, has put it this way: 'God will download our software onto his hardware until the time he gives us new hardware to run the software again for ourselves.' That gets to two things nicely: that the period after death (the Intermediate state) is a period when we are in God's presence but not active in our own bodies, and also that the more important transformation will be when we are again embodied and administering Christ's kingdom." This kingdom will consist of Heaven and Earth "joined together in a new creation", he said. Christian apocrypha include immortal human figures such as Cartaphilus and Longinus who were cursed with physical immortality for various transgressions against Christ during the Passion.


Hinduism

Hindus Hindus (; ) are people who religiously adhere to Hinduism. Jeffery D. Long (2007), A Vision for Hinduism, IB Tauris, , pages 35–37 Historically, the term has also been used as a geographical, cultural, and later religious identifier for ...
believe in an immortal soul which is reincarnated after death. According to Hinduism, people repeat a process of life, death, and rebirth in a cycle called '' samsara''. If they live their life well, their ''
karma Karma (; sa, कर्म}, ; pi, kamma, italic=yes) in Sanskrit means an action, work, or deed, and its effect or consequences. In Indian religions, the term more specifically refers to a principle of cause and effect, often descriptively ...
'' improves and their station in the next life will be higher, and conversely lower if they live their life poorly. After many life times of perfecting its karma, the soul is freed from the cycle and lives in perpetual bliss. There is no place of eternal torment in Hinduism, although if a soul consistently lives very evil lives, it could work its way down to the very bottom of the cycle. There are explicit renderings in the Upanishads alluding to a physically immortal state brought about by purification, and sublimation of the 5 elements that make up the body. For example, in the Shvetashvatara Upanishad (Chapter 2, Verse 12), it is stated "When earth, water, fire, air and sky arise, that is to say, when the five attributes of the elements, mentioned in the books on yoga, become manifest then the yogi's body becomes purified by the fire of yoga and he is free from illness, old age and death." Another view of immortality is traced to the Vedic tradition by the interpretation of Maharishi Mahesh Yogi:
That man indeed whom these (contacts)
do not disturb, who is even-minded in
pleasure and pain, steadfast, he is fit
for immortality, O best of men.Maharishi Mahesh Yogi on the Bhagavad-Gita, a New Translation and Commentary, Chapter 1–6. Penguin Books, 1969, pp. 94–95 (v 15)
To Maharishi Mahesh Yogi, the verse means, "Once a man has become established in the understanding of the permanent reality of life, his mind rises above the influence of pleasure and pain. Such an unshakable man passes beyond the influence of death and in the permanent phase of life: he attains eternal life ... A man established in the understanding of the unlimited abundance of absolute existence is naturally free from existence of the relative order. This is what gives him the status of immortal life." An Indian Tamil saint known as Vallalar claimed to have achieved immortality before disappearing forever from a locked room in 1874.


Judaism

The traditional concept of an immaterial and immortal soul distinct from the body was not found in Judaism before the Babylonian exile, but developed as a result of interaction with Persian and Hellenistic philosophies. Accordingly, the Hebrew word ''
nephesh Nephesh ( ''nép̄eš'') is a Biblical Hebrew word which occurs in the Hebrew Bible. The word refers to the aspects of sentience, and human beings and other animals are both described as being nephesh. Plants, as an example of live organisms, ar ...
'', although translated as ''"soul"'' in some older English-language Bibles, actually has a meaning closer to "living being". ''Nephesh'' was rendered in the
Septuagint The Greek Old Testament, or Septuagint (, ; from the la, septuaginta, lit=seventy; often abbreviated ''70''; in Roman numerals, LXX), is the earliest extant Greek translation of books from the Hebrew Bible. It includes several books beyond t ...
as (''psūchê''), the Greek word for ‘soul’. The only Hebrew word traditionally translated "soul" (''nephesh'') in English language Bibles refers to a living, breathing conscious body, rather than to an immortal soul. In the New Testament, the Greek word traditionally translated "soul" () has substantially the same meaning as the Hebrew, without reference to an immortal soul. ''"Soul"'' may refer either to the whole person, the self, as in "three thousand ''souls''" were converted in (see ). The
Hebrew Bible The Hebrew Bible or Tanakh (;"Tanach"
'' Sheol'' (שאול), originally a synonym of the grave – the repository of the dead or the cessation of existence, until the resurrection of the dead. This doctrine of resurrection is mentioned explicitly only in although it may be implied in several other texts. New theories arose concerning Sheol during the
intertestamental period The intertestamental period ( Protestant) or deuterocanonical period (Catholic and Eastern Orthodox) is the period of time between the events of the protocanonical books and the New Testament. Traditionally, it is considered to cover roughly fou ...
. The views about immortality in Judaism is perhaps best exemplified by the various references to this in Second Temple period. The concept of resurrection of the physical body is found in , according to which it will happen through recreation of the flesh. Resurrection of the dead is specified in detail in the extra-canonical books of Enoch, and in Apocalypse of Baruch. According to the British scholar in ancient Judaism P.R. Davies, there is "little or no clear reference ... either to immortality or to resurrection from the dead" in the
Dead Sea scrolls The Dead Sea Scrolls (also the Qumran Caves Scrolls) are ancient Jewish and Hebrew religious manuscripts discovered between 1946 and 1956 at the Qumran Caves in what was then Mandatory Palestine, near Ein Feshkha in the West Bank, on the ...
texts. Both
Josephus Flavius Josephus (; grc-gre, Ἰώσηπος, ; 37 – 100) was a first-century Romano-Jewish historian and military leader, best known for '' The Jewish War'', who was born in Jerusalem—then part of Roman Judea—to a father of priestly ...
and the
New Testament The New Testament grc, Ἡ Καινὴ Διαθήκη, transl. ; la, Novum Testamentum. (NT) is the second division of the Christian biblical canon. It discusses the teachings and person of Jesus, as well as events in first-century Chris ...
record that the Sadducees did not believe in an afterlife, but the sources vary on the beliefs of the Pharisees. The New Testament claims that the Pharisees believed in the resurrection, but does not specify whether this included the flesh or not. According to
Josephus Flavius Josephus (; grc-gre, Ἰώσηπος, ; 37 – 100) was a first-century Romano-Jewish historian and military leader, best known for '' The Jewish War'', who was born in Jerusalem—then part of Roman Judea—to a father of priestly ...
, who himself was a Pharisee, the Pharisees held that only the soul was immortal and the souls of good people will be reincarnated and "pass into other bodies," while "the souls of the wicked will suffer eternal punishment." The Book of Jubilees seems to refer to the resurrection of the soul only, or to a more general idea of an immortal soul.
Rabbinic Judaism Rabbinic Judaism ( he, יהדות רבנית, Yahadut Rabanit), also called Rabbinism, Rabbinicism, or Judaism espoused by the Rabbanites, has been the mainstream form of Judaism since the 6th century CE, after the codification of the Babylonia ...
claims that the righteous dead will be resurrected in the Messianic Age, with the coming of the
messiah In Abrahamic religions, a messiah or messias (; , ; , ; ) is a saviour or liberator of a group of people. The concepts of '' mashiach'', messianism, and of a Messianic Age originated in Judaism, and in the Hebrew Bible, in which a ''mashiach ...
. They will then be granted immortality in a perfect world. The wicked dead, on the other hand, will not be resurrected at all. This is not the only Jewish belief about the afterlife. The
Tanakh The Hebrew Bible or Tanakh (;"Tanach"
'' Lüshi Chunqiu'' that death is unavoidable. Henri Maspero noted that many scholarly works frame Taoism as a school of thought focused on the quest for immortality. Isabelle Robinet asserts that Taoism is better understood as a ''way of life'' than as a religion, and that its adherents do not approach or view Taoism the way non-Taoist historians have done. In the Tractate of Actions and their Retributions, a traditional teaching, spiritual immortality can be rewarded to people who do a certain amount of good deeds and live a simple, pure life. A list of good deeds and sins are tallied to determine whether or not a mortal is worthy. Spiritual immortality in this definition allows the soul to leave the earthly realms of afterlife and go to pure realms in the Taoist cosmology.


Zoroastrianism

Zoroastrian Zoroastrianism is an Iranian religion and one of the world's oldest organized faiths, based on the teachings of the Iranian-speaking prophet Zoroaster. It has a dualistic cosmology of good and evil within the framework of a monotheisti ...
s believe that on the fourth day after death, the human soul leaves the body and the body remains as an empty shell. Souls would go to either heaven or hell; these concepts of the afterlife in Zoroastrianism may have influenced Abrahamic religions. The Persian word for "immortal" is associated with the month "Amurdad", meaning "deathless" in Persian, in the
Iranian calendar The Iranian calendars or Iranian chronology ( fa, گاه‌شماری ایرانی, ) are a succession of calendars invented or used for over two millennia in Iran, also known as Persia. One of the longest chronological records in human history ...
(near the end of July). The month of Amurdad or Ameretat is celebrated in Persian culture as ancient Persians believed the "Angel of Immortality" won over the "Angel of Death" in this month.


Philosophical arguments for the immortality of the soul


Alcmaeon of Croton

Alcmaeon of Croton argued that the soul is continuously and ceaselessly in motion. The exact form of his argument is unclear, but it appears to have influenced Plato, Aristotle, and other later writers.


Plato

Plato Plato ( ; grc-gre, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
's ''
Phaedo ''Phædo'' or ''Phaedo'' (; el, Φαίδων, ''Phaidōn'' ), also known to ancient readers as ''On The Soul'', is one of the best-known dialogues of Plato's middle period, along with the '' Republic'' and the ''Symposium.'' The philosophica ...
'' advances four arguments for the soul's immortality: * The Cyclical Argument, or Opposites Argument explains that Forms are eternal and unchanging, and as the soul always brings life, then it must not die, and is necessarily "imperishable". As the body is mortal and is subject to physical death, the soul must be its indestructible opposite. Plato then suggests the analogy of fire and cold. If the form of cold is imperishable, and fire, its opposite, was within close proximity, it would have to withdraw intact as does the soul during death. This could be likened to the idea of the opposite charges of magnets. * The Theory of Recollection explains that we possess some non-empirical knowledge (e.g. The Form of Equality) at birth, implying the soul existed before birth to carry that knowledge. Another account of the theory is found in Plato's ''
Meno ''Meno'' (; grc-gre, Μένων, ''Ménōn'') is a Socratic dialogue by Plato. Meno begins the dialogue by asking Socrates whether virtue is taught, acquired by practice, or comes by nature. In order to determine whether virtue is teachabl ...
'', although in that case Socrates implies anamnesis (previous knowledge of everything) whereas he is not so bold in ''Phaedo''. * The Affinity Argument, explains that invisible, immortal, and incorporeal things are different from visible, mortal, and corporeal things. Our soul is of the former, while our body is of the latter, so when our bodies die and decay, our soul will continue to live. * The Argument from Form of Life or The Final Argument explains that the Forms, incorporeal and static entities, are the cause of all things in the world, and all things participate in Forms. For example, beautiful things participate in the Form of Beauty; the number four participates in the Form of the Even, etc. The soul, by its very nature, participates in the Form of Life, which means the soul can never die.


Plotinus

Plotinus offers a version of the argument that Kant calls "The Achilles of Rationalist Psychology". Plotinus first argues that the soul is
simple Simple or SIMPLE may refer to: *Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by Johnn ...
, then notes that a simple being cannot decompose. Many subsequent philosophers have argued both that the soul is simple and that it must be immortal. The tradition arguably culminates with
Moses Mendelssohn Moses Mendelssohn (6 September 1729 – 4 January 1786) was a German-Jewish philosopher and theologian. His writings and ideas on Jews and the Jewish religion and identity were a central element in the development of the '' Haskalah'', or ...
's Phaedon.


Metochites

Theodore Metochites argues that part of the soul's nature is to move itself, but that a given movement will cease only if what causes the movement is separated from the thing moved – an impossibility if they are one and the same.


Avicenna

Avicenna argued for the distinctness of the soul and the body, and the incorruptibility of the former.


Aquinas

The full argument for the immortality of the soul and
Thomas Aquinas Thomas Aquinas, Dominican Order, OP (; it, Tommaso d'Aquino, lit=Thomas of Aquino, Italy, Aquino; 1225 – 7 March 1274) was an Italian Dominican Order, Dominican friar and Catholic priest, priest who was an influential List of Catholic philo ...
' elaboration of Aristotelian theory is found in Question 75 of the First Part of the '' Summa Theologica''.


Descartes

René Descartes René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Ma ...
endorses the claim that the soul is simple, and also that this entails that it cannot decompose. Descartes does not address the possibility that the soul might suddenly disappear.


Leibniz

In early work,
Gottfried Wilhelm Leibniz Gottfried Wilhelm (von) Leibniz . ( – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat. He is one of the most prominent figures in both the history of philosophy and the history of ...
endorses a version of the argument from the simplicity of the soul to its immortality, but like his predecessors, he does not address the possibility that the soul might suddenly disappear. In his monadology he advances a sophisticated novel argument for the immortality of monads.


Moses Mendelssohn

Moses Mendelssohn Moses Mendelssohn (6 September 1729 – 4 January 1786) was a German-Jewish philosopher and theologian. His writings and ideas on Jews and the Jewish religion and identity were a central element in the development of the '' Haskalah'', or ...
's '' Phaedon'' is a defense of the simplicity and immortality of the soul. It is a series of three dialogues, revisiting the Platonic dialogue ''
Phaedo ''Phædo'' or ''Phaedo'' (; el, Φαίδων, ''Phaidōn'' ), also known to ancient readers as ''On The Soul'', is one of the best-known dialogues of Plato's middle period, along with the '' Republic'' and the ''Symposium.'' The philosophica ...
'', in which
Socrates Socrates (; ; –399 BC) was a Greek philosopher from Athens who is credited as the founder of Western philosophy and among the first moral philosophers of the ethical tradition of thought. An enigmatic figure, Socrates authored no t ...
argues for the immortality of the soul, in preparation for his own death. Many philosophers, including Plotinus, Descartes, and Leibniz, argue that the soul is simple, and that because simples cannot decompose they must be immortal. In the Phaedon, Mendelssohn addresses gaps in earlier versions of this argument (an argument that Kant calls the Achilles of Rationalist Psychology). The Phaedon contains an original argument for the simplicity of the soul, and also an original argument that simples cannot suddenly disappear. It contains further original arguments that the soul must retain its rational capacities as long as it exists.


Ethics

The possibility of clinical immortality raises a host of medical, philosophical, and religious issues and ethical questions. These include persistent vegetative states, the nature of personality over time, technology to mimic or copy the mind or its processes, social and economic disparities created by longevity, and survival of the
heat death of the universe The heat death of the universe (also known as the Big Chill or Big Freeze) is a hypothesis on the ultimate fate of the universe, which suggests the universe will evolve to a state of no thermodynamic free energy, and will therefore be un ...
.


Undesirability

Physical immortality has also been imagined as a form of eternal torment, as in the myth of
Tithonus In Greek mythology, Tithonus ( or ; grc, Τιθωνός, Tithonos) was the lover of Eos, Goddess of the Dawn. He was a prince of Troy, the son of King Laomedon by the Naiad Strymo (Στρυμώ). The mythology reflected by the fifth-century vas ...
, or in Mary Shelley's short story ''
The Mortal Immortal "The Mortal Immortal" is a short story from 1833 written by Mary Shelley. It tells the story of a man named Winzy, who drinks an elixir which makes him immortal. At first, immortality appears to promise him eternal tranquility. However, it soon be ...
'', where the protagonist lives to witness everyone he cares about die around him. For additional examples in fiction, see
Immortality in fiction Immortality is a common theme in fiction. The concept has been depicted since the '' Epic of Gilgamesh'', the oldest known work of fiction. Originally appearing in the domain of mythology, it has later become a recurring element in the genres of ...
. Kagan (2012) argues that any form of human immortality would be undesirable. Kagan's argument takes the form of a dilemma. Either our characters remain essentially the same in an immortal afterlife, or they do not: * If our characters remain basically the same – that is, if we retain more or less the desires, interests, and goals that we have now – then eventually, over an infinite stretch of time, we will get bored and find eternal life unbearably tedious. * If, on the other hand, our characters are radically changed – e.g., by God periodically erasing our memories or giving us rat-like brains that never tire of certain simple pleasures – then such a person would be too different from our current self for us to care much what happens to them. Either way, Kagan argues, immortality is unattractive. The best outcome, Kagan argues, would be for humans to live as long as they desired and then to accept death gratefully as rescuing us from the unbearable tedium of immortality.


Sociology

If human beings were to achieve immortality, there would most likely be a change in the world's social structures. Sociologists argue that human beings' awareness of their own mortality shapes their behavior. With the advancements in medical technology in extending human life, there may need to be serious considerations made about future social structures. The world is already experiencing a global
demographic shift In demography, demographic transition is a phenomenon and theory which refers to the historical shift from high birth rates and high death rates in societies with minimal technology, education (especially of women) and economic development, to lo ...
of increasingly ageing populations with lower replacement rates. The social changes that are made to accommodate this new population shift may be able to offer insight on the possibility of an immortal society. Sociology has a growing body of literature on the sociology of immortality, which details the different attempts at reaching immortality (whether actual or symbolic) and their prominence in the 21st century. These attempts include renewed attention to the dead in the West, practices of online memorialization, and biomedical attempts to increase longevity. These attempts at reaching immortality and their effects in societal structures have led some to argue that we are becoming a "Postmortal Society". Foreseen changes to societies derived from the pursuit of immortality would encompass societal paradigms and worldviews, as well as the institutional landscape. Similarly, different forms of reaching immortality might entail a significant reconfiguration of societies, from becoming more technologically-oriented to becoming more aligned with nature Immortality would increase population growth, bringing with it many consequences as for example the impact of population growth on the environment and planetary boundaries.


Politics

Although some scientists state that radical life extension, delaying and stopping aging are achievable, there are no international or national programs focused on stopping aging or on radical life extension. In 2012 in Russia, and then in the United States, Israel and the Netherlands, pro-immortality political parties were launched. They aimed to provide political support to anti-aging and radical life extension research and technologies and at the same time transition to the next step, radical life extension, life without aging, and finally, immortality and aim to make possible access to such technologies to most currently living people.


Symbols

There are numerous symbols representing immortality. The ankh is an Egyptian symbol of life that holds connotations of immortality when depicted in the hands of the gods and
pharaoh Pharaoh (, ; Egyptian: '' pr ꜥꜣ''; cop, , Pǝrro; Biblical Hebrew: ''Parʿō'') is the vernacular term often used by modern authors for the kings of ancient Egypt who ruled as monarchs from the First Dynasty (c. 3150 BC) until th ...
s, who were seen as having control over the journey of life. The Möbius strip in the shape of a
trefoil knot In knot theory, a branch of mathematics, the trefoil knot is the simplest example of a nontrivial knot. The trefoil can be obtained by joining together the two loose ends of a common overhand knot, resulting in a knotted loop. As the simplest k ...
is another symbol of immortality. Most symbolic representations of infinity or the life cycle are often used to represent immortality depending on the context they are placed in. Other examples include the Ouroboros, the Chinese fungus of longevity, the ''ten''
kanji are the logographic Chinese characters taken from the Chinese script and used in the writing of Japanese. They were made a major part of the Japanese writing system during the time of Old Japanese and are still used, along with the subsequ ...
, the phoenix, the peacock in Christianity, and the colors amaranth (in
Western culture Leonardo da Vinci's ''Vitruvian Man''. Based on the correlations of ideal Body proportions">human proportions with geometry described by the ancient Roman architect Vitruvius in Book III of his treatise ''De architectura''. image:Plato Pio-Cle ...
) and peach (in
Chinese culture Chinese culture () is one of the world's oldest cultures, originating thousands of years ago. The culture prevails across a large geographical region in East Asia and is extremely diverse and varying, with customs and traditions varying grea ...
).


See also

* Afterlife * Akal (Sikh term) * Ambrosia *
Amrita ''Amrita'' ( sa, अमृत, IAST: ''amṛta''), ''Amrit'' or ''Amata'' in Pali, (also called ''Sudha'', ''Amiy'', ''Ami'') is a Sanskrit word that means "immortality". It is a central concept within Indian religions and is often referred t ...
*
Bioethics Bioethics is both a field of study and professional practice, interested in ethical issues related to health (primarily focused on the human, but also increasingly includes animal ethics), including those emerging from advances in biology, me ...
* Biogerontology * Brooke Greenberg *
Crown of Immortality The Crown of Immortality is a literary and religious metaphor traditionally represented in art first as a laurel wreath and later as a symbolic circle of stars (often a crown, tiara, halo or aureola). The Crown appears in a number of Baroque icon ...
* Dyson's eternal intelligence * Elixir of life * Eternal return *
Eternal youth Eternal youth is the concept of human physical immortality free of ageing. The youth referred to is usually meant to be in contrast to the depredations of aging, rather than a specific age of the human lifespan. Eternal youth is common in myt ...
* Ghost *
Immortal DNA strand hypothesis The immortal DNA strand hypothesis was proposed in 1975 by John Cairns as a mechanism for adult stem cells to minimize mutations in their genomes. This hypothesis proposes that instead of segregating their DNA during mitosis in a random manner, a ...
* Immortalist Society *
Immortality in fiction Immortality is a common theme in fiction. The concept has been depicted since the '' Epic of Gilgamesh'', the oldest known work of fiction. Originally appearing in the domain of mythology, it has later become a recurring element in the genres of ...
* Internal alchemy * Lich * List of people claimed to be immortal in myth and legend * Methuselah Mouse Prize * Molecular nanotechnology * Negligible senescence * Tipler's Omega Point * Organlegging * Posthuman * Resurrection * Queen Mother of the West * Simulated reality * Suspended animation *
Undead The undead are beings in mythology, legend, or fiction that are deceased but behave as if alive. Most commonly the term refers to corporeal forms of formerly-alive humans, such as mummies, vampires, and zombies, who have been reanimated b ...
* Regeneration (theology)


Footnotes


Notes


References

*


Further reading

* * * * * * * * * * * * * * * * * * * * *


External links

*
Scientists are Close to Finding a Way to be Immortal
* Turritopsis nutriculabr>Palscience
Meet The Only Immortal Species on Planet Earth
The Methuselah Foundation
Aubrey de Grey's non-profit organization dedicated to finding a cure for aging
KurzweilAI.net
Ray Kurzweil resource site
BiologicalGerontology.com
Chris Smelick's Biogerontology site
Vitae Institute
Chris Smelick's non-profit organization
ELPIs Theory
Marios Kyriazis' theory of human biological immortality
Immortality Institute
Scientific and sociological discussions, activism, research


Religious and spiritual prospects for immortality


"Death and Immortality"
''Dictionary of the History of Ideas'', etext at the University of Virginia Library
"Immortality"
''Immortality – What Will Eternal Life Be Like?'' *
The Immortality of the Soul and the Resurrection of the Body
' Lecture by Heinrich J. Vogel
''An Essay on the Scriptural Doctrine of Immortality''
by James Challis
''Eternity: Christ's Return, Chiliasm, Resurrection of the Dead, Judgment, Hell, Luther on Eternity, Heaven''
J.P. Meyer, ''The Northwestern Lutheran'', 22 August 1954, Vol. 41, # 17 to 14 April 1957, Vol. 44, No. 8
"How you Can Have Eternal Life"
Jack Graham, PowerPoint Ministries, Christianity.com
Immortality
Taoist essay, personaltao.com
The Trial to Conquer Death
Ancient Scientific Yoga – The First Atom's Final Attempt

A review by Dr. Peter Fenwick of the book Human Immortality by Mohammad Samir Hossain


In literature

* Mary Shelley's
The Mortal Immortal
' {{Death Immortality, Afterlife Life extension Mythological powers Technological utopianism