Immortality

===Causes of death===
{{Main|Death}}
There are three main causes of death: [[aging|natural aging]], [[disease]], and [[physical trauma|injury]].<ref>{{cite journal |last=Hayflick |first=L. |year=2007 |title=Biological aging is no longer an unsolved problem |journal=Annals of the New York Academy of Sciences |volume=1100 |issue=1 |pages=1–13 |doi=10.1196/annals.1395.001 |pmid=17460161 |bibcode=2007NYASA1100....1H |s2cid=14685889}}{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> 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,<ref name="Garreau">{{cite news |first=Joel |last=Garreau |author-link=Joel Garreau |date=31 October 2007 |title=The Invincible Man |newspaper=[[The Washington Post]] |page=C‑01 |url=https://www.washingtonpost.com/wp-dyn/content/article/2007/10/30/AR2007103002222_pf.html}}</ref> defines [[aging]] as "a collection of cumulative changes to the [[molecular]] and [[cell (biology)|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 theory of aging|DNA damage]], [[oncology|oncogenic]] [[cell nucleus|nuclear]] [[mutation]]s and [[epimutation]]s, cell [[senescence]], [[mitochondria]]l 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 [[Strategies for engineered negligible senescence|engineered negligible senescence]]. There is also a huge body of knowledge indicating that change is characterized by the loss of molecular fidelity.<ref>{{cite book |last1=Bernstein |first1=C. |last2=Bernstein |first2=H. |year=1991 |title=Aging, Sex, and DNA Repair |publisher=Academic Press |place=San Diego, CA |isbn=978-0120928606}} {{ISBN|0120928604}}</ref>

====Disease====
Disease is theoretically surmountable by technology. In short, it is an abnormal condition affecting the body of an organism, something the body should not typically have to deal with its natural make up.<ref>{{cite web |title=Classification of diseases functioning and disability |date=23 July 2021 |url=https://www.cdc.gov/nchs/icd.htm}}</ref> 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 disease|Parkinson's]] and [[Alzheimer's disease|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. [[Vaccine]]s 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]] [[disaster relief operation|response]] remains a determining factor in surviving severe trauma.<ref name=walker>{{cite book |last=Walker |first=Peter |date=1991 |title=International Search and Rescue Teams |series=League Discussion Paper |publisher=[[IFRC|League of the Red Cross and Red Crescent Societies]] |place=Geneva, CH}}</ref> A body that could automatically repair itself from severe trauma, such as speculated uses for [[nanotechnology]], would mitigate this factor. The brain cannot be risked to trauma if a continuous physical life is to be maintained. This aversion to trauma risk to the brain would naturally result in significant behavioral changes that would render physical immortality undesirable for some people.

====Environmental change====
{{Unreferenced section|date=November 2022}}
Organisms otherwise unaffected by these causes of death would still face the problem of obtaining sustenance (whether from currently available agricultural processes or from hypothetical future technological processes) in the face of changing availability of suitable resources as environmental conditions change. After avoiding aging, disease, and trauma, death through resource limitation is still possible, such as [[Hypoxia (medical)|hypoxia]] or [[starvation]].

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 [[Hazard rate|in any finite period]] is greater than zero. Mathematically, this is an aspect of achieving [[Indefinite lifespan#Actuarial escape velocity|'actuarial escape velocity']].