Immortality

==Ethics==
{{See also|Life extension#Ethics and politics}}

The possibility of clinical immortality raises a host of medical, philosophical, and religious issues and ethical questions. These include [[persistent vegetative state]]s, the nature of personality over time, technology to mimic or copy the mind or its processes, [[Human enhancement#Inequality and Social Disruption|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 the myth of [[Tithonus]], or in [[Mary Shelley]]'s short story ''[[The Mortal Immortal]]'', where the protagonist lives to witness everyone he cares about die around him. For additional examples in fiction, see [[Immortality in fiction]].

[[Shelly Kagan|Kagan]] (2012){{refn|name=Kagan-2012-Death}} 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.{{refn|
name=Kagan-2012-Death|
{{cite book
 |first=Shelly |last=Kagan |author-link=Shelly Kagan
 |year=2012
 |title=Death
 |place=New Haven, CT
 |publisher=Yale University Press
 |pages=238–246
}}<br/>
Kagan notes that his argument is an adaptation of a similar argument given by the British philosopher [[Bernard Williams|B. Williams]] (1973).<ref>
{{cite book
 |first=B. |last=Williams |author-link=Bernard Williams
 |year=1973
 |title=Problems of the Self
}}
</ref>
}}