Immortality
Immortality is the concept of a condition of potentially infinite or indeterminate lifespan. "Non-mortals" would be immune to many or all current aspects of mortality, fragile form, poor health, and disease. Recent research in cosmology is uncertain about the fate of the universe. Immortality, by its purest definition, would depend entirely on the continued presence of the environment wherein a being exists.
Types of immortality
Quantum immortality is the name for the speculation that the Everett many-worlds interpretation of quantum mechanics implies that a conscious being cannot cease to be. The idea is highly controversial. Suppose a physicist tries to detonate a nuclear bomb next to him. In almost all parallel universes, the nuclear explosion would vaporize the physicist. However, there is a small set of alternate universes in which the physicist somehow survives. The idea behind quantum immortality is that the physicist would only be able to experience the universes in which he survives, even though they may be a small subset of the possible universes. In this way, the physicist would appear from his own standpoint to be living forever.
Jacques Cousteau, in the preface to his book The Ocean World, expressed his meditations on physical immortality, as a part of life and its adaptive processes: 'Death,' Cousteau states, 'is fundamental to evolution;' and 'evolution is fundamental to survival'. He concludes that, biologically speaking, 'immortality does not present a possible means to avoid death': "Mortal or immortal, [an organism] must die."
Spiritual Immortality, on the other hand, is a belief that is expressed in nearly every religious tradition. In both Western and Eastern religions, the spirit is an energy or force that transcends the mortal shell, and returns to either the heavens or the cycle of life, directly or indirectly depending on the tradition.
Medical science may extend human life, and some believe that future medicine will make human body self-sustainable and capable of living indefinitely. Others, like Cousteau, believe that biological forms have inherent limitations in their design--primarily, their fragility and inability to immediately morph to fit the environment. A way around Cousteau's predicament may someday present itself in the ability to "exist" outside of the biological form. Technological immortality is a concept which postulates that the biological nature of humanity is only temporary; should technology permit, people may circumvent death and evolution, simply by taking artificial forms. Conceivably, this could reach a point in which physical danger is nullified or nearly-nullified.
A very important aspect of the current scientific thought concerning immortality is that nanotechnology will play an essential role in extreme life extension.
Would this strange new serum be good news? According to the vast majority of ethicists, "Not at all," since unending biological functioning is not what is at issue in immortality. Ultimately, what one desires is some sort of permanent preservation of personal identity, not just unceasing metabolic integrity.
This brings up the philosophical issue of the meaning of consciousness. As another thought experiment, suppose a surgeon replaces part of a man's brain with a pacemaker (this is actually done to treat Parkinsons). After this procedure is done, the patient comes out of his anesthesia feeling like the same person. For the intentions of this expirement, suppose that doctors have already fully understand the brain and are able to successfully move sections of the brain's neural network and memories onto hardware where they can perfectly emulate the "architecture" of the brain. Over a period of time, suppose that the individual has many more operations with the intent of gradually replacing parts of his brain with computer hardware. Eventually, the man has a brain made entirely out of computer parts. The man comes out claiming that he is the same person as before. He has the same memories and acts the same.
Now suppose that instead of replacing parts of his brain with hardware, he copies the entire brain onto hardware. The computerized version of this man's brain acts the same way, and claims that it is the same man who underwent the procedure. The original man is still alive, however. Are the machine and the man the same person? Are they somehow linked in conscious? These are the types of situations that illustrate the lack of knowledge concerning the meaning of consciousness that we as a civilization currently posess.
Second, even if the eager engineer were to modify his machine (due to popular demand) so as to configure all the neural pathways of Jones* to match Jones, this would still present problems. Jones does not want a perfect duplicate to exit the machine at the second trip, but Jones himself wants to exit the machine. Granted, if all were done discretely, Jones' wife, Jones' mistress, and Jones' poker buddies would think that Jones* was Jones, and even Jones* himself might think he was Jones, but thinking that such-n-such is true is hardly a guarantee that such-n-such really is true, as any jilted lover can attest.
Third, the Jones/Jones* problem is at issue in religious accounts of resurrection. Since humans share substantial quanta of their atoms with others who have preceded them in history (i.e., coffins leak, eventually, and nature cycles the organic material back through the biosphere), any resurrection cannot use all the original atomic collection for each individual to be resurrected. New material would be required; thus, worries about a duplicate thinking that s/he was the original person arise for the pious as well as for the pagan.
Apparently, on any account where immortality requires a remanufacture of a body in order to maintain character identity, seemingly insurmountable difficulties present themselves. Some views of quantum immortality approach the general issue of immortality differently.
Some extropian futurists propose that, thanks to exponentially accelerating computing power, it will someday be possible to "upload" human consciousness onto a computer system, and live 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. Gradually more and more components would be added until the person's entire brain functions were handled by artificial devices, without any sharp transitions that would lead to identity issues as mentioned above. At this point, the human body would become only an accessory and the mind could be transferred to any sufficiently powerful computer. A person in this state would then be essentially immortal, short of cataclysmic destruction of the entire civilization and their computers.
See also Afterlife. Immortality InstituteConcepts of immortality
Considerations of immortality usually bring to mind the idea of unending existence, a freedom from the concerns of annihilation and death. Often times, talk of the immortality of the soul arises in conjunction with talk of immortality. The ideas of science and religion find common goals in the perpetuity of man's existence. Unending existence is too simple a condition for immortality
As a thought experiment, suppose a doctor relates to his patient that a strange new serum has been discovered. Upon taking this serum, all of the standard biological processes which lead to aging are cured: (1) The effects of reaching the end of a finite turnover of cells are no longer noted in the patient, (2) Chromosomal aberrations cease, thus eliminating copying errors when cells duplicate, and; (3) the accumulation of metabolic, inadvertently destructive or post-translational errors from cell division (along with waste products) no longer occur. The only side effect, unfortunately, is that it uses the full gamut of sodium, potassium, and calcium ions in the patient's brain to jump-start the serum process; the brain is destroyed instantly. The freedom from concerns of annihilation and death is insufficient for immortality
Essential to many of the world's religions is a doctrine of an eternal afterlife. But well known narratives from Christianity and Islam show why freedom from annihilation and death could (in principle) not be desirable:
Instances from other religions could be adduced. Mere perpetual existence is not enough. Ultimately, one desires that this existence be of a desirable quality.When talk of a "soul" arises
When talk of a "soul" arises, immediately, concerns of psychology and metaphysics become relevant. Suppose, as yet, another thought experiment:
According to most ethicists, the engineer has not done Jones a favor even if Jones could, as it were, "wash, rinse, and repeat" this whole cycle indefinitely. First off, it is anything but clear that the human exiting the machine at the second trip is Jones. Call the person who steps out (whether he is Jones or not) "Jones*". Presuming that memory is a physiological structure encoded by neural pathways, Jones* would not preserve the memory of Jones, since Jones* would not have the encoded neural pathways of an 80-year-old, but only of a 30-year-old. Hence, all that Jones was (after 30, anyway) as the collection of memory experiences upon second entry into the device is lost; thus, Jones is effectively dead. Immortality would offer little if the best results obtainable were a recurring coda of temporal duplicates. Religion
Immortality, combined with benevolence, may make the person a deity worshipped popularly, such as the Taoist Eight Immortals of China. Most often, such people gained immortality through enlightenment by other immortals.