May the Force be with you Princess
Source: a Reddit comment [1]
[1] https://www.reddit.com/r/movies/comments/5kkzmo/comment/dbon...
source: the comments in that thread.
... and the new Rogue One movie. If you haven't seen it -- it is worth watching.
Death is not 'a part of life', but a nuisance. Not all species 'die' (e.g. jellyfish, hydra, possibly lobsters, flatworms).
And 'the Force' is fictional and does not apply to Carrie Fisher.
As long as we have our species, it is enevitable we will be achieving immortality.
My point being - every death is a tragedy.
The two notions are orthogonal. Nuisances of every kind are regular parts of life.
Our triumph over death will be met with a similar awe as our successful invention of the hedonovat, a device that suspends a living creature in goo while supplying everything it needs to live forever and supplying sensory inputs of nothing but pleasure and happiness.
The idea that "residual potential lives on in others" is irrelevant - there should be no need to die to inspire someone else. Moreover, even if inspired by Einstein, no-one will not produce exactly the same work as Einstein would have, had he lived. So that notion is refuted, and would become ever more definitively so over the accumulated years and contributions of an indefinite lifespan.
Solving the problem of death includes removing the overwhelming preference for death in cases where it is the only relief from a terrible quality of life, so your chronic pain example gets swept aside.
The is no such thing as a "hedonovat" and your depiction of it sounds frankly ridiculous. Hoping to enable an indefinite human lifespan with a high quality of life is not ridiculous.
Death is only loss and pain.
Why would you want to live forever? The human condition is predicated on birth and death. As an academic exercise, I think birth without death would be a bit like moving from a northern climate to a southern climate, where work ethic goes out the window because there is no season in which work cannot be done (winter).
If we live forever, at what point do we taste the urgency of living?
If it's a procedure and not inherited, either it goes along with technology supplying humanity with cheap nigh-unlimited energy and thus space travel, uploading of minds or it's a two-caste world in which the same immortal persons hold the mortal masses at bay with any means necessary. If it's immortality for all (say through a virus that spreads naturally), it's a world where people have to be naturally sterile and only the priviledged get to have children, you get to wait thousands of years before you can procreate due to a place being free because of accidental deaths or no one gets to have children (but a governing body through technical means, arifical wombs).
Also, I can imagine relative immortality would render global nuclear war an inconvenience, with proper protection you could maybe wait out the aftermath and start again?
[0] "history doesn't repeat itself, it rhymes"
Its a metaphor for spirituality, and its pretty obvious that the strict deterministic materialist worldview is far from proven and that many people have spiritual beliefs that they feel 100% justified as having.
Not everything is horrible because we don't have immortality. If anything, we'll hit our extinction event well before then, assuming its even possible for complex mammals to have. No, we're not flatworms and can't have the aging solutions of flatworms.
I think its okay to feel comforted by death. When my dad died, it hurt, but I was happy his suffering has ended. I was happy he had a long life and raised three boys who loved him. You absolutely can accept and even welcome death in some ways. Life isn't all roses and chocolates. Death is currently the only solution we have to terminal suffering, for example.
People have spiritual beliefs when they try to explain things that they can not understand. Other people abuse this by telling them that they have special knowledge and that they can explain those phenomena, or even more subtle, that there is somebody out there who can explain it to them, at some point, in some manner. All this without providing the slightest chance of falsification, meaning basically they can assert whatever they like.
So in my eyes, no, people are not really justified in having those beliefs: they could just as well accept that certain things are (now, and possibly forever) unknowable.
That said, relativity has nothing intrinsically non-deterministic about it [1], and whether quantum mechanics is deterministic or not is open to debate [2].
[1]: https://en.wikipedia.org/wiki/Indeterminism#Classical_and_re...
[2]: https://en.wikipedia.org/wiki/Interpretations_of_quantum_mec...