Almost all of our sun’s radiation, which supports all life on Earth because it can get converted into lipids, carbohydrates and proteins, goes unused every single second. It is sufficient to provide enough energy to power the life of billions of planets like Earths simultaneously. This renders any fear about overpopulation absurd. Regardless, whether we succeed in giving our lives permanent meanings by reversing all adverse aspects of aging, the birth rate keeps exceeding its supposedly counterbalancing death rate by several percent. This will inevitably cause our mother-planet to become too small for sustaining all instances of life, which deserve every imaginable support to stay alive as long as they feel not to be the same as their surroundings because this allows them to perceive and respond. Killing them would be the same as taking away an irreplaceable uniquely responding option, which deserves its own opportunity to adapt to its experiences by actively striving to find the best subjectively best situation on its own. Every form of consciousness, which can distinguish itself as not being the same as its surroundings is like an imperatively visible element (IVE), which would be demoted to an IHE, if killed. It would lose out on opportunities to improve its self-perception. It would lose its irreplaceable unique self-identity and perception; hence, causing its memories to become inevitably lost forever. It may take long until people start defining the value of life based on the same criteria by which we distinguish between IHEs and IVEs. As long as any form of life is forced to go backwards from an IVE to an IHE, it is losing its most valuable feature, i.e. irreplaceable self-identity and self-perception. Humans may never know which animals would be deprived of their most valuable features as soon as they are getting prevented from making a difference between themselves and their surroundings.
But this is all just intellectual theory because as soon as we start reaching for eternal life, we must define what it is to minimize the risk that it will be taken away from anyone, who deserves to keep it. That is why I applied the same criteria I use to distinguish between IHE and IVE. The new rule of thumb for deserving to live is: any critter, who subjectively perceives itself as not exactly the same as its surrounding background noise, i.e. who possesses at least one feature by which it differs from its surroundings, should be allowed to keep living in its environment, because it has passed the critical threshold, above which a uniquely irreplaceable instance of constantly adapting self-identity and self-perception must be assumed. Depriving any critter from its opportunities and benefits to remain active within its environment would be morally wrong because if we did this to humans, it would be considered murder. But then, any animals navigating in similar levels of consciousness would lose the same as their aging human counterparts and would suffer the same kind of loss, which humans would feel when gradually losing their ability to subjectively perceive themselves as something other than their surroundings. All this hypothetical writing above, which may never reach any practical significance because homo Sapiens tends to care less for other species, is only necessary because of the huge overlap between the declining self-perception and self-identity capabilities of dying humans, especially when dying of Alzheimer, dementia or any other age-related disease interfering with memory formation and retrieval, without which no unique self-identity and self-perception can be maintained any longer. Once lost, it can never be restored again. This is the sad about humans gradually losing the very feature, which has given them the inherently innate features of an IVE all their lives. Unfortunately, after having lost their subjective perception of their most defining IVE feature, i.e. to perceive themselves as something other than their surrounding background living environment, they can no longer maintain any form of self-identity and self-perception, not even a completely static one, because it imperatively depends on memory formation, retrieval, responses and adaptations. This demotes their mental and cognitive status from an IVE to and IHE; hence, causing them to disappear from their own subjective perception. This implies that their subjective perception can no longer be brought back to what it was between birth and loss of the capabilities associated with any IVE.
Note that no living IVE (i.e. visible subject) will ever stay the same as time goes on. It is in constant flax of gradually transitioning with every new impression and every change it notices. No IVE resembling critter can ever return to exactly any of its It past self-perception and self-identity. This makes it imperatively irreproducible and thus, guarantees its indefinitely high value, which cannot be compensated for in any way by any currency.
Seriously considering immortality requires us to break away from many of our long overdue obsolete concepts. Although we are not even close to accomplishing immortality yet by rejuvenating and then remain forever young, healthy, energetic, curious, adventurous, flexible, adaptive, ambitious, innovative, creative, passionate and full of love for all aspects of life, we would benefit a lot from replacing our old mortal with immortal concepts of life because this is a precondition for succeeding in transitioning faster from mortal to immortal beings. For our generation, this will make the difference between life and death.