Immortality

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The Fountain of Eternal Life in Cleveland, Ohio is described as symbolizing "Man rising above death, reaching upward to God and toward Peace."

 

Immortality is eternal life, being exempt from death, unending existence. Some modern species may possess biological immortality. 

Certain 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. 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 physical trauma; although mind uploading could solve that if it proved possible. Whether the process of internal endoimmortality is delivered within the upcoming years depends chiefly on research (and in neuron research in the case of endoimmortality through an immortalized cell line) in the former view and perhaps is an awaited goal in the latter case.

In religious contexts, immortality is often stated to be one of the promises of God (or other deities) to human beings who show goodness or else follow divine law. 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 and debate.

Definitions

Scientific

Life extension technologies promise a path to complete rejuvenation. Cryonics 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, it is not known if it is possible for humans. 

Mind uploading is the transference of brain states from a human brain to an alternative medium providing similar functionality. Assuming the process to be possible and repeatable, this would provide immortality to the computation of the original brain, as predicted by futurists such as Ray Kurzweil.

Religious

The belief in an afterlife is a fundamental tenet of most religions, including Hinduism, Buddhism, Jainism, Sikhism, Christianity, Zoroastrianism, Islam, Judaism, and the Bahá'í Faith; however, the concept of an immortal soul is not. The "soul" itself has different meanings and is not used in the same way in different religions and different denominations of a religion. For example, various branches of Christianity have disagreeing views on the soul's immortality and its relation to the body.

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. Active pursuit of physical immortality can either be based on scientific trends, such as cryonics, digital immortality, breakthroughs in rejuvenation or predictions of an impending technological singularity, or because of a spiritual belief, such as those held by Rastafarians or Rebirthers.

Causes of death

There are three main causes of death: aging, disease and physical trauma. 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, a leading researcher in the field, defines aging as "a collection of cumulative changes to the molecular and cellular structure of an adult organism, which result in essential metabolic processes, but which also, once they progress far enough, increasingly disrupt metabolism, resulting in pathology and death." The current causes of aging in humans are cell loss (without replacement), DNA damage, oncogenic nuclear mutations and epimutations, cell senescence, mitochondrial mutations, lysosomal aggregates, extracellular aggregates, random extracellular cross-linking, immune system 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 via 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 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 is becoming better understood. Neurodegenerative diseases like Parkinson's and Alzheimer's 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. Genes associated with type 1 diabetes and certain types of cancer have been discovered, allowing for new therapies to be developed. Artificial devices attached directly to the nervous system 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 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. Being the seat of consciousness, 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, you could still starve to death. 

If there is no limitation on the degree of gradual mitigation of risk then it is possible that the cumulative probability 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

Human chromosomes (grey) capped by telomeres (white)

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. 

Biologists 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 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, 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, 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. Its immortal adaptation has allowed it to spread from its original habitat in the Caribbean to "all over the world".
• Hydra is a genus belonging to the phylum Cnidaria, 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 necessity for senescence: a defining feature of life is that it takes in free energy from the environment and unloads its entropy 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, 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 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.

Prospects for human biological immortality

Life-extending substances

There are some known naturally occurring and artificially produced chemicals that may increase the lifetime or life-expectancy of a person or organism, such as resveratrol.

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 chromosomes, 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) 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, 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, one of the founders of nanotechnology, postulated cell repair devices, including ones operating within cells and utilizing 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, 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 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 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, 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 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.

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 regarding 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, Hesiod, 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 these were Amphiaraus, Ganymede, Ino, Iphigenia, Menelaus, Peleus, and a great part 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 was killed by Zeus only to be resurrected and transformed into a major deity. In some versions of the Trojan War myth, Achilles, 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, who was killed by Achilles, seems to have received a similar fate. Alcmene, Castor, Heracles, and Melicertes were also among the figures sometimes considered to have been resurrected to physical immortality. According to Herodotus' Histories, the 7th century BC 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 philosophical idea of an immortal soul was a belief first appearing with either Pherecydes or the Orphics, and most importantly advocated by Plato 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. The parallel between these traditional beliefs and the later resurrection of Jesus was not lost on the early Christians, as Justin Martyr 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." (1 Apol. 21).

Buddhism

The goal of Hinayana is Arhatship and Nirvana. By contrast, the goal of Mahayana is Buddhahood. 

According to one Tibetan Buddhist teaching, Dzogchen, individuals can transform the physical body into an immortal body of light called the rainbow body.

Christianity

Adam and Eve condemned to mortality. Hans Holbein the Younger, Danse Macabre, 16th century

 

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, and this belief is known as Universal resurrection.

N.T. Wright, a theologian and former Bishop of Durham, has said many people forget the physical aspect of what Jesus promised. He told Time: "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.

Hinduism

Representation of a soul undergoing punarjanma. Illustration from Hinduism Today, 2004

 

Hindus 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 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 akasa 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.

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, although translated as "soul" in some older English Bibles, actually has a meaning closer to "living being". Nephesh was rendered in the Septuagint as ψυχή (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" (ψυχή) has substantially the same meaning as the Hebrew, without reference to an immortal soul. ‘Soul’ may refer to the whole person, the self: ‘three thousand souls’ were converted in Acts 2:41 (see Acts 3:23).

The Hebrew Bible speaks about 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 Daniel 12:1–4 although it may be implied in several other texts. New theories arose concerning Sheol during the intertestamental period. 

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 2 Maccabees, according to which it will happen through recreation of the flesh. Resurrection of the dead also appears in detail in the extra-canonical books of Enoch, and in Apocalypse of Baruch. According to the British scholar in ancient Judaism Philip R. Davies, there is “little or no clear reference … either to immortality or to resurrection from the dead” in the Dead Sea scrolls texts. Both Josephus and the New Testament 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, 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.”  Jubilees seems to refer to the resurrection of the soul only, or to a more general idea of an immortal soul.

Rabbinic Judaism claims that the righteous dead will be resurrected in the Messianic Age with the coming of the messiah. 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 is not specific about the afterlife, so there are wide differences in views and explanations among believers.

Taoism

It is repeatedly stated in 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

Zoroastrians 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 (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's Phaedo 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, 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, 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'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' elaboration of Aristotelian theory is found in Question 75 of the First Part of the Summa Theologica.

Descartes

René Descartes 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 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'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, in which Socrates 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.

Undesirability

Physical immortality has also been imagined as a form of eternal torment, as in Mary Shelley's short story "The Mortal Immortal", the protagonist of which witnesses everyone he cares about dying around him. Jorge Luis Borges explored the idea that life gets its meaning from death in the short story "The Immortal"; an entire society having achieved immortality, they found time becoming infinite, and so found no motivation for any action. In his book Thursday's Fictions, and the stage and film adaptations of it, Richard James Allen tells the story of a woman named Thursday who tries to cheat the cycle of reincarnation to get a form of eternal life. At the end of this fantastical tale, her son, Wednesday, who has witnessed the havoc his mother's quest has caused, forgoes the opportunity for immortality when it is offered to him. Likewise, the novel Tuck Everlasting depicts immortality as "falling off the wheel of life" and is viewed as a curse as opposed to a blessing. In the anime Casshern Sins humanity achieves immortality due to advances in medical technology; however, the inability of the human race to die causes Luna, a Messianic figure, to come forth and offer normal lifespans because she believed that without death, humans could not live. Ultimately, Casshern takes up the cause of death for humanity when Luna begins to restore humanity's immortality. In Anne Rice's book series The Vampire Chronicles, vampires are portrayed as immortal and ageless, but their inability to cope with the changes in the world around them means that few vampires live for much more than a century, and those who do often view their changeless form as a curse.

In his book Death, Yale philosopher Shelly Kagan 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 worlds' 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 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.

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

The ankh

 

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 pharaohs, who were seen as having control over the journey of life. The Möbius strip in the shape of a trefoil knot 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, the phoenix, the peacock in Christianity, and the colors amaranth (in Western culture) and peach (in Chinese culture).

Fiction

Immortality is a popular subject in fiction, as it explores humanity's deep-seated fears and comprehension of its own mortality. Immortal beings and species abound in fiction, especially fantasy fiction, and the meaning of "immortal" tends to vary. The Epic of Gilgamesh, one of the first literary works, is primarily a quest of a hero seeking to become immortal.

Some fictional beings are completely immortal (or very nearly so) in that they are immune to death by injury, disease and age. Sometimes such powerful immortals can only be killed by each other, as is the case with the Q from the Star Trek series. Even if something can't be killed, a common plot device involves putting an immortal being into a slumber or limbo, as is done with Morgoth in J. R. R. Tolkien's The Silmarillion and the Dreaming God of Pathways Into Darkness. Storytellers often make it a point to give weaknesses to even the most indestructible of beings. For instance, Superman is supposed to be invulnerable, yet his enemies were able to exploit his now-infamous weakness: Kryptonite.

Many fictitious species are said to be immortal if they cannot die of old age, even though they can be killed through other means, such as injury. Modern fantasy elves often exhibit this form of immortality. Other creatures, such as vampires and the immortals in the film Highlander, can only die from beheading. The classic and stereotypical vampire is typically slain by one of several very specific means, including a silver bullet (or piercing with other silver weapons), a stake through the heart (perhaps made of consecrated wood), or by exposing them to sunlight.

Soul

From Wikipedia, the free encyclopedia

Image of the soul in the Rosarium philosophorum.

 

The soul, in many religious, philosophical, and mythological traditions, is the incorporeal essence of a living being. Soul or psyche (Ancient Greek: ψυχή psūkhḗ, of ψύχειν psū́khein, "to breathe") are the mental abilities of a living being: reason, character, feeling, consciousness, memory, perception, thinking, etc. Depending on the philosophical system, a soul can either be mortal or immortal. In Judeo-Christianity, only human beings have immortal souls (although immortality is disputed within Judaism and may have been influenced by Plato). For example, the Catholic theologian Thomas Aquinas attributed "soul" (anima) to all organisms but argued that only human souls are immortal.

Other religions (most notably Hinduism and Jainism) hold that all living things from the smallest bacterium to the largest of mammals are the souls themselves (Atman, jiva) and have their physical representative (the body) in the world. The actual self is the soul, while the body is only a mechanism to experience the karma of that life. Thus if we see a tiger then there is a self-conscious identity residing in it (the soul), and a physical representative (the whole body of the tiger, which is observable) in the world. Some teach that even non-biological entities (such as rivers and mountains) possess souls. This belief is called animism. Greek philosophers, such as Socrates, Plato, and Aristotle, understood that the soul (ψυχή psūchê) must have a logical faculty, the exercise of which was the most divine of human actions. At his defense trial, Socrates even summarized his teaching as nothing other than an exhortation for his fellow Athenians to excel in matters of the psyche since all bodily goods are dependent on such excellence (Apology 30a–b).

The current consensus of modern science is that there is no evidence to support the existence of the soul when traditionally defined as the spiritual breath of the body. In metaphysics, the concept of "Soul" may be equated with that of "Mind" in order to refer to the consciousness and intellect of the individual.

Etymology

The Modern English word "soul", derived from Old English sáwol, sáwel, was first attested in the 8th century poem Beowulf v. 2820 and in the Vespasian Psalter 77.50 . It is cognate with other German and Baltic terms for the same idea, including Gothic saiwala, Old High German sêula, sêla, Old Saxon sêola, Old Low Franconian sêla, sîla, Old Norse sála and Lithuanian siela. Deeper etymology of the Germanic word is unclear. 

The original concept behind the Germanic root is thought to mean “coming from or belonging to the sea (or lake)”, because of the Germanic and pre-Celtic belief in souls emerging from and returning to sacred lakes, Old Saxon sêola (soul) compared to Old Saxon sêo (sea).

Synonyms

The Koine Greek Septuagint uses ψυχή (psyche) to translate Hebrew נפש (nephesh), meaning "life, vital breath", and specifically refers to a mortal, physical life, but in English it is variously translated as "soul, self, life, creature, person, appetite, mind, living being, desire, emotion, passion"; an example can be found in Genesis 1:21:

Hebrew – וַיִּבְרָא אֱלֹהִים, אֶת-הַתַּנִּינִם הַגְּדֹלִים; וְאֵת כָּל-נֶפֶשׁ הַחַיָּה הָרֹמֶשֶׂת

Septuagint – καὶ ἐποίησεν ὁ θεὸς τὰ κήτη τὰ μεγάλα καὶ πᾶσαν ψυχὴν ζῴων ἑρπετῶν.

Vulgate – Creavitque Deus cete grandia, et omnem animam viventem atque motabilem.

Authorized King James Version – "And God created great whales, and every living creature that moveth."

The Koine Greek word ψυχή (psychē), "life, spirit, consciousness", is derived from a verb meaning "to cool, to blow", and hence refers to the breath, as opposed to σῶμα (soma), meaning "body". Psychē occurs juxtaposed to σῶμα, as seen in Matthew 10:28:

Greek – καὶ μὴ φοβεῖσθε ἀπὸ τῶν ἀποκτεννόντων τὸ σῶμα, τὴν δὲ ψυχὴν μὴ δυναμένων ἀποκτεῖναι· φοβεῖσθε δὲ μᾶλλον τὸν δυνάμενον καὶ ψυχὴν καὶ σῶμα ἀπολέσαι ἐν γεέννῃ.

Vulgate – et nolite timere eos qui occidunt corpus animam autem non possunt occidere sed potius eum timete qui potest et animam et corpus perdere in gehennam.

Authorized King James Version (KJV) – "And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell."

Paul the Apostle used ψυχή (psychē) and πνεῦμα (pneuma) specifically to distinguish between the Jewish notions of נפש (nephesh) and רוח ruah (spirit) (also in the Septuagint, e.g. Genesis 1:2 רוּחַ אֱלֹהִים = πνεῦμα θεοῦ = spiritus Dei = "the Spirit of God").

Religious views

Ancient Near East

The souls of Pe and Nekhen towing the royal bargue on a relief of Ramesses II's temple in Abydos.

 

In the ancient Egyptian religion, an individual was believed to be made up of various elements, some physical and some spiritual. Similar ideas are found in ancient Assyrian and Babylonian religion. Kuttamuwa, an 8th-century BCE royal official from Sam'al, ordered an inscribed stele erected upon his death. The inscription requested that his mourners commemorate his life and his afterlife with feasts "for my soul that is in this stele". It is one of the earliest references to a soul as a separate entity from the body. The 800-pound (360 kg) basalt stele is 3 ft (0.91 m) tall and 2 ft (0.61 m) wide. It was uncovered in the third season of excavations by the Neubauer Expedition of the Oriental Institute in Chicago, Illinois.

Bahá'í

The Bahá'í Faith affirms that "the soul is a sign of God, a heavenly gem whose reality the most learned of men hath failed to grasp, and whose mystery no mind, however acute, can ever hope to unravel". Bahá'u'lláh stated that the soul not only continues to live after the physical death of the human body, but is, in fact, immortal. Heaven can be seen partly as the soul's state of nearness to God; and hell as a state of remoteness from God. Each state follows as a natural consequence of individual efforts, or the lack thereof, to develop spiritually. Bahá'u'lláh taught that individuals have no existence prior to their life here on earth and the soul's evolution is always towards God and away from the material world.

Buddhism

Buddhism teaches the principle of impermanence, that all things are in a constant state of flux: all is changing, and no permanent state exists by itself. This applies to human beings as much as to anything else in the cosmos. Thus, a human being has no permanent self. According to this doctrine of anatta (Pāli; Sanskrit: anātman) – "no-self" or "no soul" – the words "I" or "me" do not refer to any fixed thing. They are simply convenient terms that allow us to refer to an ever-changing entity.

The anatta doctrine is not a kind of materialism. Buddhism does not deny the existence of "immaterial" entities, and it (at least traditionally) distinguishes bodily states from mental states. Thus, the conventional translation of anatta as "no-soul" can be confusing. If the word "soul" simply refers to an incorporeal component in living things that can continue after death, then Buddhism does not deny the existence of the soul. Instead, Buddhism denies the existence of a permanent entity that remains constant behind the changing corporeal and incorporeal components of a living being. Just as the body changes from moment to moment, so thoughts come and go, and there is no permanent state underlying the mind that experiences these thoughts, as in Cartesianism. Conscious mental states simply arise and perish with no "thinker" behind them. When the body dies, Buddhists believe the incorporeal mental processes continue and are reborn in a new body. Because the mental processes are constantly changing, the being that is reborn is neither entirely different from, nor exactly the same as, the being that died. However, the new being is continuous with the being that died – in the same way that the "you" of this moment is continuous with the "you" of a moment before, despite the fact that you are constantly changing.

Buddhist teaching holds that a notion of a permanent, abiding self is a delusion that is one of the causes of human conflict on the emotional, social, and political levels. They add that an understanding of anatta provides an accurate description of the human condition, and that this understanding allows us to pacify our mundane desires. 

Various schools of Buddhism have differing ideas about what continues after death. The Yogacara school in Mahayana Buddhism said there are Store consciousness which continue to exist after death. In some schools, particularly Tibetan Buddhism, the view is that there are three minds: very subtle mind, which does not disintegrate in death; subtle mind, which disintegrates in death and which is "dreaming mind" or "unconscious mind"; and gross mind, which does not exist when one is sleeping. Therefore, gross mind is less permanent than subtle mind, which does not exist in death. Very subtle mind, however, does continue, and when it "catches on", or coincides with phenomena, again, a new subtle mind emerges, with its own personality/assumptions/habits, and that entity experiences karma in the current continuum. 

Plants were said to be non-sentient (無情), but Buddhist monks are required to not cut or burn trees, because some sentient beings rely on them. Some Mahayana monks said non-sentient beings such as plants and stones have Buddha-nature.

Certain modern Buddhists, particularly in Western countries, reject—or at least take an agnostic stance toward—the concept of rebirth or reincarnation. Stephen Batchelor discusses this in his book Buddhism Without Beliefs. Others point to research that has been conducted at the University of Virginia as proof that some people are reborn.

Christianity

Soul carried to Heaven by William Bouguereau

 

Most Christians understand the soul as an ontological reality distinct from, yet integrally connected with, the body. Its characteristics are described in moral, spiritual, and philosophical terms. Richard Swinburne (1934- ), an Orthodox Christian philosopher of religion at Oxford University, wrote that "it is a frequent criticism of substance dualism that dualists cannot say what souls are. Souls are immaterial subjects of mental properties. They have sensations and thoughts, desires and beliefs, and perform intentional actions. Souls are essential parts of human beings". According to a common Christian eschatology, when people die, their souls will be judged by God and determined to go to Heaven or to Hell. Though all major branches of Christianity – Catholics, Eastern Orthodox, Oriental Orthodox, Church of the East, Evangelical, and mainline Protestants – teach that Jesus Christ plays a decisive role in the Christian salvation process, the specifics of that role and the part played by individual persons or by ecclesiastical rituals and relationships, is a matter of wide diversity in official church teaching, theological speculation and popular practice. Some Christians believe that if one has not repented of one's sins and has not trusted in Jesus Christ as Lord and Savior, one will go to Hell and suffer eternal damnation or eternal separation from God. Some hold a belief that babies (including the unborn) and those with cognitive or mental impairments who have died will be received into Heaven on the basis of God's grace through the sacrifice of Jesus.

Other Christians understand the soul as the life, and believe that the dead are sleeping (Christian conditionalism). This belief is traditionally accompanied by the belief that the unrighteous soul will cease to exist instead of suffering eternally (annihilationism). Believers will inherit eternal life either in Heaven, or in a Kingdom of God on earth, and enjoy eternal fellowship with God. 

There are also beliefs in universal salvation. 

The Damned Soul. Drawing by Michelangelo Buonarroti c. 1525

Trichotomy of the soul

Augustine (354-430), one of western Christianity's most influential early Christian thinkers, described the soul as "a special substance, endowed with reason, adapted to rule the body". Some Christians espouse a trichotomic view of humans, which characterizes humans as consisting of a body (soma), soul (psyche), and spirit (pneuma). However, the majority of modern Bible scholars point out how the concepts of "spirit" and of "soul" are used interchangeably in many biblical passages, and so hold to dichotomy: the view that each human comprises a body and a soul. Paul said that the "body wars against" the soul, "For the word of God is living and active and sharper than any two-edged sword, and piercing as far as the division of soul and spirit" (Heb 4:12 NASB), and that "I buffet my body", to keep it under control. Trichotomy was changed to dichotomy as tenet of Christian faith at the Council of Constantinople in 869, which Roman Catholics regard as the 8th Ecumenical Council.

Origin of the soul

The "origin of the soul" has provided a vexing question in Christianity. The major theories put forward include soul creationism, traducianism, and pre-existence. According to soul creationism, God creates each individual soul created directly, either at the moment of conception or some later time. According to traducianism, the soul comes from the parents by natural generation. According to the preexistence theory, the soul exists before the moment of conception. There have been differing thoughts regarding whether human embryos have souls from conception, or whether there is a point between conception and birth where the fetus acquires a soul, consciousness, and/or personhood. Stances in this question might play a role in judgements on the morality of abortion.

Views of various denominations

The present Catechism of the Catholic Church defines the soul as "the innermost aspect of humans, that which is of greatest value in them, that by which they are in God's image described as 'soul' signifies the spiritual principle in man". All souls living and dead will be judged by Jesus Christ when he comes back to earth. The Catholic Church teaches that the existence of each individual soul is dependent wholly upon God: "The doctrine of the faith affirms that the spiritual and immortal soul is created immediately by God."

Depiction of the soul on a 17th-century tombstone at the cemetery of the Old Dutch Church of Sleepy Hollow

 

Protestants generally believe in the soul's existence, but fall into two major camps about what this means in terms of an afterlife. Some, following Calvin, believe in the immortality of the soul and conscious existence after death, while others, following Luther, believe in the mortality of the soul and unconscious "sleep" until the resurrection of the dead. Various new religious movements deriving from Adventism—including Christadelphians, Seventh-day Adventists, and Jehovah's Witnesses—similarly believe that the dead do not possess a soul separate from the body and are unconscious until the resurrection. 

The Church of Jesus Christ of Latter-day Saints teaches that the spirit and body together constitute the Soul of Man (Mankind). "The spirit and the body are the soul of man." Latter-day Saints believe that the soul is the union of a pre-existing, God-made spirit and a temporal body, which is formed by physical conception on earth. After death, the spirit continues to live and progress in the Spirit world until the resurrection, when it is reunited with the body that once housed it. This reuniting of body and spirit results in a perfect soul that is immortal and eternal and capable of receiving a fulness of joy. Latter-day Saint cosmology also describes "intelligences" as the essence of consciousness or agency. These are co-eternal with God, and animate the spirits. The union of a newly-created spirit body with an eternally-existing intelligence constitutes a "spirit birth" and justifies God's title "Father of our spirits".

Hinduism

Hindu last rites for departed souls

 

Ātman is a Sanskrit word that means inner self or soul. In Hindu philosophy, especially in the Vedanta school of Hinduism, Ātman is the first principle, the true self of an individual beyond identification with phenomena, the essence of an individual. In order to attain liberation (moksha), a human being must acquire self-knowledge (atma jnana), which is to realize that one's true self (Ātman) is identical with the transcendent self Brahman.

The six orthodox schools of Hinduism believe that there is Ātman (self, essence) in every being.

In Hinduism and Jainism, a jiva (Sanskrit: जीव, jīva, alternative spelling jiwa; Hindi: जीव, jīv, alternative spelling jeev) is a living being, or any entity imbued with a life force.

In Jainism, jiva is the immortal essence or soul of a living organism (human, animal, fish or plant etc.) which survives physical death. The concept of Ajiva in Jainism means "not soul", and represents matter (including body), time, space, non-motion and motion. In Jainism, a Jiva is either samsari (mundane, caught in cycle of rebirths) or mukta (liberated).

The concept of jiva in Jainism is similar to atman in Hinduism. However, some Hindu traditions differentiate between the two concepts, with jiva considered as individual self, while atman as that which is universal unchanging self that is present in all living beings and everything else as the metaphysical Brahman. The latter is sometimes referred to as jiva-atman (a soul in a living body). According to Brahma Kumaris, the soul is an eternal point of light.

Islam

The Quran, the holy book of Islam, distinguishes between the immortal Rūḥ (translated as spirit, consciousness, pneuma or "soul") and the mortal Nafs (translated as self, ego, psyche or "soul"). The immortal Rūḥ "drives" the mortal Nafs, which comprises temporal desires and perceptions necessary for living. One of the passages in the Quran that mention Rûh occur in chapter 17 ("The Night Journey"), whereas a mention of Nafs occurs in Chapter 39 ("The Throngs"):

And they ask you, [O Muhammad], about the Rûh. Say, "The Rûh is of the affair of my Lord. And mankind has not been given of knowledge except a little.

— Quran 17:85

It is Allah that takes the Nafs at death: and those that die not (He takes it) during their sleep: then those on whom He has passed the Decree of death He keeps back (their Nafs from returning); but the rest He sends back for a term appointed. Verily in this are Signs for those who contemplate

— Qur'an 39:42

Jainism

In Jainism, every living being, from plant or bacterium to human, has a soul and the concept forms the very basis of Jainism. According to Jainism, there is no beginning or end to the existence of soul. It is eternal in nature and changes its form until it attains liberation. 

The soul (Jīva) is basically categorized in one of two ways based on its present state.

1. Liberated Souls – These are souls which have attained liberation (moksha) and never become part of the life cycle again.
2. Non-Liberated Souls – The souls of any living being which are stuck in the life cycle of 4 forms; Manushya Gati (Human Being), Tiryanch Gati (Any other living being), Dev Gati (Heaven) and Narak Gati (Hell).

Until the time the soul is liberated from the saṃsāra (cycle of repeated birth and death), it gets attached to one of these bodies based on the karma (actions) of the individual soul. Irrespective of which state the soul is in, it has got the same attributes and qualities. The difference between the liberated and non-liberated souls is that the qualities and attributes are manifested completely in case of siddha (liberated soul) as they have overcome all the karmic bondages whereas in case of non-liberated souls they are partially exhibited.

Concerning the Jain view of the soul, Virchand Gandhi said

the soul lives its own life, not for the purpose of the body, but the body lives for the purpose of the soul. If we believe that the soul is to be controlled by the body then soul misses its power.

Judaism

The Hebrew terms נפש nefesh (literally "living being"), רוח ruach (literally "wind"), נשמה neshamah (literally "breath"), חיה chayah (literally "life") and יחידה yechidah (literally "singularity") are used to describe the soul or spirit.

In Judaism the soul was believed to be given by God to Adam as mentioned in Genesis,

Then the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul.

— Genesis 2:7

Judaism relates the quality of one's soul to one's performance of the commandments (mitzvot) and reaching higher levels of understanding, and thus closeness to God. A person with such closeness is called a tzadik. Therefore, Judaism embraces the commemoration of the day of one's death, nahala/Yahrtzeit and not the birthday as a festivity of remembrance, for only toward the end of life's struggles, tests and challenges could human souls be judged and credited for righteousness. Judaism places great importance on the study of the souls.

Kabbalah and other mystic traditions go into greater detail into the nature of the soul. Kabbalah separates the soul into five elements, corresponding to the five worlds:

1. Nefesh, related to natural instinct.
2. Ruach, related to emotion and morality.
3. Neshamah, related to intellect and the awareness of God.
4. Chayah, considered a part of God, as it were.
5. Yechidah. This aspect is essentially one with God.

Kabbalah also proposed a concept of reincarnation, the gilgul.

Scientology

The Scientology view is that a person does not have a soul, it is a soul. A person is immortal, and may be reincarnated if they wish. The Scientology term for the soul is "thetan", derived from the Greek word "theta", symbolizing thought. Scientology counselling (called auditing) addresses the soul to improve abilities, both worldly and spiritual.

Shamanism

The belief in soul dualism found throughout most Austronesian shamanistic traditions. The reconstructed Proto-Austronesian word for the "body soul" is *nawa ("breath", "life", or "vital spirit"). It is located somewhere in the abdominal cavity, often in the liver or the heart (Proto-Austronesian *qaCay). The "free soul" is located in the head. Its names are usually derived from Proto-Austronesian *qaNiCu ("ghost", "spirit [of the dead]"), which also apply to other non-human nature spirits. The "free soul" is also referred to in names that literally mean "twin" or "double", from Proto-Austronesian *duSa ("two"). A virtuous person is said to be one whose souls are in harmony with each other, while an evil person is one whose souls are in conflict.

The "free soul" is said to leave the body and journey to the spirit world during sleep, trance-like states, delirium, insanity, and death. The duality is also seen in the healing traditions of Austronesian shamans, where illnesses are regarded as a "soul loss" and thus to heal the sick, one must "return" the "free soul" (which may have been stolen by an evil spirit or got lost in the spirit world) into the body. If the "free soul" can not be returned, the afflicted person dies or goes permanently insane.

In some ethnic groups, there can also be more than two souls. Like among the Tagbanwa people, where a person is said to have six souls - the "free soul" (which is regarded as the "true" soul) and five secondary souls with various functions.

Kalbo Inuit groups believe that a person has more than one type of soul. One is associated with respiration, the other can accompany the body as a shadow. In some cases, it is connected to shamanistic beliefs among the various Inuit groups. Also Caribou Inuit groups believed in several types of souls.

The shaman heals within the spiritual dimension by returning 'lost' parts of the human soul from wherever they have gone. The shaman also cleanses excess negative energies, which confuse or pollute the soul.

Sikhism

Sikhism considers soul (atma) to be part of God (Waheguru). Various hymns are cited from the holy book Guru Granth Sahib (SGGS) that suggests this belief. "God is in the Soul and the Soul is in the God." The same concept is repeated at various pages of the SGGS. For example: "The soul is divine; divine is the soul. Worship Him with love." and "The soul is the Lord, and the Lord is the soul; contemplating the Shabad, the Lord is found."

The atma or soul according to Sikhism is an entity or "spiritual spark" or "light" in our body because of which the body can sustain life. On the departure of this entity from the body, the body becomes lifeless – No amount of manipulations to the body can make the person make any physical actions. The soul is the ‘driver’ in the body. It is the roohu or spirit or atma, the presence of which makes the physical body alive. 

Many religious and philosophical traditions support the view that the soul is the ethereal substance – a spirit; a non material spark – particular to a unique living being. Such traditions often consider the soul both immortal and innately aware of its immortal nature, as well as the true basis for sentience in each living being. The concept of the soul has strong links with notions of an afterlife, but opinions may vary wildly even within a given religion as to what happens to the soul after death. Many within these religions and philosophies see the soul as immaterial, while others consider it possibly material.

Taoism

According to Chinese traditions, every person has two types of soul called hun and po (魂 and 魄), which are respectively yang and yin. Taoism believes in ten souls, sanhunqipo (三魂七魄) "three hun and seven po". A living being that loses any of them is said to have mental illness or unconsciousness, while a dead soul may reincarnate to a disability, lower desire realms, or may even be unable to reincarnate.

Other religious beliefs and views

Charon (Greek) who guides dead souls to the Underworld. 4th century BCE.

 

In theological reference to the soul, the terms "life" and "death" are viewed as emphatically more definitive than the common concepts of "biological life" and "biological death". Because the soul is said to be transcendent of the material existence, and is said to have (potentially) eternal life, the death of the soul is likewise said to be an eternal death. Thus, in the concept of divine judgment, God is commonly said to have options with regard to the dispensation of souls, ranging from Heaven (i.e., angels) to hell (i.e., demons), with various concepts in between. Typically both Heaven and hell are said to be eternal, or at least far beyond a typical human concept of lifespan and time.

According to Louis Ginzberg, soul of Adam is the image of God. Every soul of human also escapes from the body every night, rises up to heaven, and fetches new life thence for the body of man.

Spirituality, New Age, and new religions

Brahma Kumaris

In Brahma Kumaris, human souls are believed to be incorporeal and eternal. God is considered to be the Supreme Soul, with maximum degrees of spiritual qualities, such as peace, love and purity.

Theosophy

In Helena Blavatsky's Theosophy, the soul is the field of our psychological activity (thinking, emotions, memory, desires, will, and so on) as well as of the so-called paranormal or psychic phenomena (extrasensory perception, out-of-body experiences, etc.). However, the soul is not the highest, but a middle dimension of human beings. Higher than the soul is the spirit, which is considered to be the real self; the source of everything we call "good"—happiness, wisdom, love, compassion, harmony, peace, etc. While the spirit is eternal and incorruptible, the soul is not. The soul acts as a link between the material body and the spiritual self, and therefore shares some characteristics of both. The soul can be attracted either towards the spiritual or towards the material realm, being thus the "battlefield" of good and evil. It is only when the soul is attracted towards the spiritual and merges with the Self that it becomes eternal and divine.

Anthroposophy

Rudolf Steiner claimed classical trichotomic stages of soul development, which interpenetrated one another in consciousness:

• The "sentient soul", centering on sensations, drives, and passions, with strong conative (will) and emotional components;
• The "intellectual" or "mind soul", internalizing and reflecting on outer experience, with strong affective (feeling) and cognitive (thinking) components; and
• The "consciousness soul", in search of universal, objective truths.

Miscellaneous

In Surat Shabda Yoga, the soul is considered to be an exact replica and spark of the Divine. The purpose of Surat Shabd Yoga is to realize one's True Self as soul (Self-Realisation), True Essence (Spirit-Realisation) and True Divinity (God-Realisation) while living in the physical body.

Similarly, the spiritual teacher Meher Baba held that "Atma, or the soul, is in reality identical with Paramatma the Oversoul — which is one, infinite, and eternal...[and] [t]he sole purpose of creation is for the soul to enjoy the infinite state of the Oversoul consciously."

Eckankar, founded by Paul Twitchell in 1965, defines Soul as the true self; the inner, most sacred part of each person.

Philosophical views

The ancient Greeks used the word "ensouled" to represent the concept of being "alive", indicating that the earliest surviving western philosophical view believed that the soul was that which gave the body life. The soul was considered the incorporeal or spiritual "breath" that animates (from the Latin, anima, cf. "animal") the living organism.

Francis M. Cornford quotes Pindar by saying that the soul sleeps while the limbs are active, but when one is sleeping, the soul is active and reveals "an award of joy or sorrow drawing near" in dreams.

Erwin Rohde writes that an early pre-Pythagorean belief presented the soul as lifeless when it departed the body, and that it retired into Hades with no hope of returning to a body.

Socrates and Plato

Plato (left) and Aristotle (right), a detail of The School of Athens, a fresco by Raphael.

Drawing on the words of his teacher Socrates, Plato considered the psyche to be the essence of a person, being that which decides how we behave. He considered this essence to be an incorporeal, eternal occupant of our being. Plato says that even after death, the soul exists and is able to think. He believed that as bodies die, the soul is continually reborn in subsequent bodies. However, Aristotle believed that only one part of the soul was immortal namely the intellect (logos). The Platonic soul consists of three parts:

1. the logos, or logistikon (mind, nous, or reason)
2. the thymos, or thumetikon (emotion, spiritedness, or masculine)
3. the eros, or epithumetikon (appetitive, desire, or feminine)

The parts are located in different regions of the body:

1. logos is located in the head, is related to reason and regulates the other part.
2. thymos is located near the chest region and is related to anger.
3. eros is located in the stomach and is related to one's desires.

Plato also compares the three parts of the soul or psyche to a societal caste system. According to Plato's theory, the three-part soul is essentially the same thing as a state's class system because, to function well, each part must contribute so that the whole functions well. Logos keeps the other functions of the soul regulated.

Aristotle

The structure of the souls of plants, animals, and humans, according to Aristotle, with Bios, Zoê, and Psūchê

 

Aristotle (384–322 BCE) defined the soul, or Psūchê (ψυχή), as the "first actuality" of a naturally organized body, and argued against its separate existence from the physical body. In Aristotle's view, the primary activity, or full actualization, of a living thing constitutes its soul. For example, the full actualization of an eye, as an independent organism, is to see (its purpose or final cause). Another example is that the full actualization of a human being would be living a fully functional human life in accordance with reason (which he considered to be a faculty unique to humanity). For Aristotle, the soul is the organization of the form and matter of a natural being which allows it to strive for its full actualization. This organization between form and matter is necessary for any activity, or functionality, to be possible in a natural being. Using an artifact (non-natural being) as an example, a house is a building for human habituation, but for a house to be actualized requires the material (wood, nails, bricks, etc.) necessary for its actuality (i.e. being a fully functional house). However, this does not imply that a house has a soul. In regards to artifacts, the source of motion that is required for their full actualization is outside of themselves (for example, a builder builds a house). In natural beings, this source of motion is contained within the being itself. Aristotle elaborates on this point when he addresses the faculties of the soul. 

The various faculties of the soul, such as nutrition, movement (peculiar to animals), reason (peculiar to humans), sensation (special, common, and incidental) and so forth, when exercised, constitute the "second" actuality, or fulfillment, of the capacity to be alive. For example, someone who falls asleep, as opposed to someone who falls dead, can wake up and live their life, while the latter can no longer do so. 

Aristotle identified three hierarchical levels of natural beings: plants, animals, and people, having three different degrees of soul: Bios (life), Zoë (animate life), and Psuchë (self-conscious life). For these groups, he identified three corresponding levels of soul, or biological activity: the nutritive activity of growth, sustenance and reproduction which all life shares (Bios); the self-willed motive activity and sensory faculties, which only animals and people have in common (Zoë); and finally "reason", of which people alone are capable (Pseuchë). 

Aristotle's discussion of the soul is in his work, De Anima (On the Soul). Although mostly seen as opposing Plato in regard to the immortality of the soul, a controversy can be found in relation to the fifth chapter of the third book: In this text both interpretations can be argued for, soul as a whole can be deemed mortal, and a part called "active intellect" or "active mind" is immortal and eternal. Advocates exist for both sides of the controversy, but it has been understood that there will be permanent disagreement about its final conclusions, as no other Aristotelian text contains this specific point, and this part of De Anima is obscure. Further, Aristotle states that the soul helps humans find the truth and understanding the true purpose or role of the soul is extremely difficult.

Avicenna and Ibn al-Nafis

Following Aristotle, Avicenna (Ibn Sina) and Ibn al-Nafis, an Arab physician, further elaborated upon the Aristotelian understanding of the soul and developed their own theories on the soul. They both made a distinction between the soul and the spirit, and the Avicennian doctrine on the nature of the soul was influential among the Scholastics. Some of Avicenna's views on the soul include the idea that the immortality of the soul is a consequence of its nature, and not a purpose for it to fulfill. In his theory of "The Ten Intellects", he viewed the human soul as the tenth and final intellect. 

While he was imprisoned, Avicenna wrote his famous "Floating Man" thought experiment to demonstrate human self-awareness and the substantial nature of the soul. He told his readers to imagine themselves suspended in the air, isolated from all sensations, which includes no sensory contact with even their own bodies. He argues that in this scenario one would still have self-consciousness. He thus concludes that the idea of the self is not logically dependent on any physical thing, and that the soul should not be seen in relative terms, but as a primary given, a substance. This argument was later refined and simplified by René Descartes in epistemic terms, when he stated: "I can abstract from the supposition of all external things, but not from the supposition of my own consciousness."

Avicenna generally supported Aristotle's idea of the soul originating from the heart, whereas Ibn al-Nafis rejected this idea and instead argued that the soul "is related to the entirety and not to one or a few organs". He further criticized Aristotle's idea whereby every unique soul requires the existence of a unique source, in this case the heart. al-Nafis concluded that "the soul is related primarily neither to the spirit nor to any organ, but rather to the entire matter whose temperament is prepared to receive that soul," and he defined the soul as nothing other than "what a human indicates by saying "I".

Thomas Aquinas

Following Aristotle (whom he referred to as "the Philosopher") and Avicenna, Thomas Aquinas (1225–74) understood the soul to be the first actuality of the living body. Consequent to this, he distinguished three orders of life: plants, which feed and grow; animals, which add sensation to the operations of plants; and humans, which add intellect to the operations of animals.

Concerning the human soul, his epistemological theory required that, since the knower becomes what he knows, the soul is definitely not corporeal—if it is corporeal when it knows what some corporeal thing is, that thing would come to be within it. Therefore, the soul has an operation which does not rely on a body organ, and therefore the soul can exist without a body. Furthermore, since the rational soul of human beings is a subsistent form and not something made of matter and form, it cannot be destroyed in any natural process. The full argument for the immortality of the soul and Aquinas' elaboration of Aristotelian theory is found in Question 75 of the First Part of the Summa Theologica.

Immanuel Kant

In his discussions of rational psychology, Immanuel Kant (1724–1804) identified the soul as the "I" in the strictest sense, and argued that the existence of inner experience can neither be proved nor disproved.

We cannot prove a priori the immateriality of the soul, but rather only so much: that all properties and actions of the soul cannot be recognized from materiality.

It is from the "I", or soul, that Kant proposes transcendental rationalization, but cautions that such rationalization can only determine the limits of knowledge if it is to remain practical.

Philosophy of mind

Gilbert Ryle's ghost in the machine argument, which is a rejection of Descartes' mind–body dualism, can provide a contemporary understanding of the soul/mind, and the problem concerning its connection to the brain/body.

James Hillman

Psychologist James Hillman's archetypal psychology is an attempt to restore the concept of the soul, which Hillman viewed as the "self-sustaining and imagining substrate" upon which consciousness rests. Hillman described the soul as that "which makes meaning possible, [deepens] events into experiences, is communicated in love, and has a religious concern", as well as "a special relation with death". Departing from the Cartesian dualism "between outer tangible reality and inner states of mind", Hillman takes the Neoplatonic stance that there is a "third, middle position" in which soul resides. Archetypal psychology acknowledges this third position by attuning to, and often accepting, the archetypes, dreams, myths, and even psychopathologies through which, in Hillman's view, soul expresses itself.

Science

The current scientific consensus across all fields is that there is no evidence for the existence of any kind of soul in the traditional sense. Many modern scientists, such as Julien Musolino, hold that the mind is merely a complex machine that operates on the same physical laws as all other objects in the universe. According to Musolino, there is currently no scientific evidence whatsoever to support the existence of the soul; he claims there is also considerable evidence that seems to indicate that souls do not exist.

Neuroscience

Neuroscience as an interdisciplinary field, and its branch of cognitive neuroscience particularly, operates under the ontological assumption of physicalism. In other words, it assumes—in order to perform its science—that only the fundamental phenomena studied by physics exist. Thus, neuroscience seeks to understand mental phenomena within the framework according to which human thought and behavior are caused solely by physical processes taking place inside the brain, and it operates by the way of reductionism by seeking an explanation for the mind in terms of brain activity.

To study the mind in terms of the brain several methods of functional neuroimaging are used to study the neuroanatomical correlates of various cognitive processes that constitute the mind. The evidence from brain imaging indicates that all processes of the mind have physical correlates in brain function. However, such correlational studies cannot determine whether neural activity plays a causal role in the occurrence of these cognitive processes (correlation does not imply causation) and they cannot determine if the neural activity is either necessary or sufficient for such processes to occur. Identification of causation, and of necessary and sufficient conditions requires explicit experimental manipulation of that activity. If manipulation of brain activity changes consciousness, then a causal role for that brain activity can be inferred. Two of the most common types of manipulation experiments are loss-of-function and gain-of-function experiments. In a loss-of-function (also called "necessity") experiment, a part of the nervous system is diminished or removed in an attempt to determine if it is necessary for a certain process to occur, and in a gain-of-function (also called "sufficiency") experiment, an aspect of the nervous system is increased relative to normal. Manipulations of brain activity can be performed with direct electrical brain stimulation, magnetic brain stimulation using transcranial magnetic stimulation, psychopharmacological manipulation, optogenetic manipulation, and by studying the symptoms of brain damage (case studies) and lesions. In addition, neuroscientists are also investigating how the mind develops with the development of the brain.

Physics

Physicist Sean M. Carroll has written that the idea of a soul is incompatible with quantum field theory (QFT). He writes that for a soul to exist: "Not only is new physics required, but dramatically new physics. Within QFT, there can't be a new collection of 'spirit particles' and 'spirit forces' that interact with our regular atoms, because we would have detected them in existing experiments."

Some theorists have invoked quantum indeterminism as an explanatory mechanism for possible soul/brain interaction, but neuroscientist Peter Clarke found errors with this viewpoint, noting there is no evidence that such processes play a role in brain function; Clarke concluded that a Cartesian soul has no basis from quantum physics.

Parapsychology

Some parapsychologists have attempted to establish, by scientific experiment, whether a soul separate from the brain exists, as is more commonly defined in religion rather than as a synonym of psyche or mind. Milbourne Christopher (1979) and Mary Roach (2010) have argued that none of the attempts by parapsychologists have yet succeeded.

Weight of the soul

In 1901 Duncan MacDougall conducted an experiment in which he made weight measurements of patients as they died. He claimed that there was weight loss of varying amounts at the time of death; he concluded the soul weighed 21 grams. The physicist Robert L. Park has written that MacDougall's experiments "are not regarded today as having any scientific merit" and the psychologist Bruce Hood wrote that "because the weight loss was not reliable or replicable, his findings were unscientific."