The first sophonts in the Terragen Sphere that could be considered potentially immortal were the first AIs; these entities could continue to operate for an arbitrary period. In practice, very few aioids and vecs from this early period survive in their original form, although a few still exist in one form or another following substantial alterations and upgrades.
After the development of reliable life-extension technology, the average biological sophont living in the Sephirotic Empires could also live for as long as they chose, barring accidents. When back-up technology became possible, even accidents need not cause the sophont's life to come to an end. But few modosophonts of any kind persist unchanged for more than a few thousand years, and many bionts cease to exist in their original state after a millennium or less.There are many ways in which the extended life-span Sephirotic citizen (whether ril or virtual, biont or aioid) might come to a conclusion. The options include the following:
1: Voluntary termination (suicide): there are many forms of ritual that accompany voluntary termination of one's own life, and some spectacular methods of achieving this aim, for instance the black hole at Sco BH-76. Another unusual method of voluntary termination is being eaten by carnivores, especially sophont carnivores such as carnivorous rianths.
2:Indefinitely prolonged existence, as practiced by the Immortalist sect. This option is problematic for modosophonts, because of memory limitations. A modosophont can only recall a certain proportion of the events in eir lifetime, and this proportion decreases when the modosophont has an extended lifespan. After several thousand years a modosophont with an indefinitely prolonged lifespan would gradually become a completely new individual, with only residual memories of any earlier events or characteristics. Basically the body might live forever but the mind inside would slowly change into an almost completely new individual. Immortalists point out that this process of slow alteration and loss of memory happens to all biological sophonts anyway, and that there are many forms of artificial memory that can be used to reduce the problem of forgetfulness.
3:Reincarnation. The sophont has their memories copied out and then wiped and starts existence over anew, either literally being reborn as a child and growing up again or as a 'tabula rasa' adult (to one level or another). The old memories are sometimes made available again at some predetermined time or when the person reaches a certain age. Alternately the memories simply trickle back in gradually (and often only partially).
In some polities a person can choose to reincarnate/transform into a non-sophont being, live out that life, be recorded and stored and reincarnated again and do this for some period until being brought back as a sophont, then allowed to experience the total store of memories they had accumulated over time.
4:Uploading into a virtual afterlife, of which there are many variants. Any modosophont (even a virtual one, or an aioid) can be uploaded or transferred into such a virtual paradise, which may resemble some traditional religious heaven concepts, or may be very different indeed. One problem with such a paradise is boredom. In early attempts at paradisiacal afterlifes, the inhabitants became bored after a few thousand years of subjective time, and many opted to terminate their own existence, dying once more in heaven. This problem has largely been solved by increasing the interest factor in such artificial heavens, making the virch as complex, and as challenging, and difficult to understand, as the real world. That is one reason why virtual entities, particularly those in afterlives, occupy such extensive computronium banks: they value a rich environment, and have high standards. Many virtual afterlifes include riddles, complexities and diversity that appear to be greater than that of the outside/real world, and the resources required for such environments are considerable.
There are also rumours of a number of virtual (and real-life) hells, where 'sinners' can be punished for an indefinite period. One such rumour concerns the so-called Queen of Pain.
5:Ascension or Transcension (the difference being whether the resulting transapient retains a significant fraction of the characteristics of the original or not). Both ascension and transcension are risky, and can fail drastically, so this option is not quite as popular as it might be. Modosophonts in the Keter Dominion and the TRHN are trained from birth to be prepared for ascension and transcension, and these processes are very common in those empires. Methods of this kind that allow safer ascension/transcension events are slowly becoming more prevalent in other empires in the Current Era.
6:Merging with other modosophont(s) to become a new (modosophont) being. This option was problematic in the past, as merging very different mentalities is a very difficult process. But with modern neurotechnology and psychoengineering, group minds, tribe minds and merged minds are commonplace on many worlds.
7:Absorption by a transapient or an archai in one of many ways. The processes involved are not well understood by modosophont level society, but by studying the results some idea of what is involved can be obtained. In some cases the transapient/archai might modify the modosophont during the absorption process, perhaps causing the citizen to ascend or transcend in the process; or the transapient might merge the citizen with other citizens already in the transapient/archai's databanks. One form of merger involves the deconstruction of the mind of the citizen, which is reduced to a mass of data, adding to a communal database made up of all the characteristics of all absorbed citizens combined. Often all the memories of the citizens concerned are similarly combined, making up a communal memory with multiple points-of-view which could presumably only be fully understood by a transapient of suitable toposophic form. The individual citizen would be completely subsumed in this case, although presumably with their consent.
8:Storage. The citizen could be stored unchanged, ready to be activated when deemed necessary by the transapient/archai (perhaps as a consultant of some sort), or awoken at a time chosen by eirself.
9:Accidental death or murder with total (or substantial) data loss. Some unwilling victims may have failed to back-up their minds, or the procedure may have failed; others might accept life-extension procedures but reject uploading technology, and so on.
10:Death from old age. A number of citizens reject life extension technology (or in the case of vecs, replacement parts) for religious or philosophical reasons, or may live for an arbitrary period then have the technology reversed or removed, allowing their life to end naturally. Mortalists of various kinds often end their lives in this way. Many mortalists believe in a religious afterlife of some sort or another, or in the persistence of the influence of a human life in the collective memory.
11:More than one of the above. With copying and backups any particular citizen could be stored, merged, deconstructed, commit suicide and also live forever, if circumstances permit.
An unknown but large fraction of transapients and archai cease to be active after a certain period. Neither the processes involved nor the final results are truly understood at the modosophont level. Some are equivalent to the options mentioned above and others may have not equivalent. At least some of these vanished gods and godlings are thought to have left the Local Brane altogether and may now continue to exist in other locations which are no longer accessible from this universe. A considerable fraction of those vanished transapients were once modosophonts themselves, or contain within themselves the merged remnants of former modosophont citizens.
Immortality - Text by M. Alan Kazlev While literal physical immortality remains a contentious point in a universe that, although vast, is still finite, the wonders of modern medical nano mean that all citizens of the Civilized Galaxy, to say nothing of the higher toposophic ai, are potentially immortal; at least on angelnetted worlds. See also life-extension, afterlife.