Immortality, a false good idea

Immortality is trendy. According to some so-called "transhumanists", it is the promise of artificial intelligence at short or medium term, at the very least before the end of the 21st century. Considering the current advances in this field, we are bound to see amazing achievements which will shake our very notions of identity (what I am) and humanity (what we are). If I can transfer, one piece after another, neuron after neuron, organ after organ, each and every element which makes my identity into a human or machine clone of myself, supposing this is sound in theory and doable in practice, will this duplicate of myself still be myself? The same one? Another one? And if I make several clones, which one will be the "true" one? Do such questions make any sense at all? All this looks really like just another, high-tech, version of the Ship of Theseus, and our transhumanists provide no more no less than the ancient philosophers answers to the difficult questions about permanence and identity this old story has been setting, more than two thousand years ago.
None of those dreamers seem to provide a clear idea of how this immortality is supposed to be lived in practice, if ever we achieve it. A neverending old age? Not really a happy prospect! No, to be sure, immortality is only worth it if it goes with eternal youth! And even so, being alone in this condition, and seeing everyone else growing old and die, friends, family, my children and their children, does not that amount to buying an eternity of sorrow? Not sure how long one could stand that. But wait, don't worry, our transhumanists will claim, this is no problem because just everybody will be immortal! Everybody? You mean every single one of the 10 billion people expected to be living by 2100? Or only a very small minority of wealthy happy few? But let's assume the (highly unlikely) prospect of generalized immortality by 2050. In that case it will not be 10 but 15 billion immortal people at the end of the century if natality does not abate.That's clearly not sustainable. But maybe when everyone is immortal, there will be no need to have children anymore, and maybe even at some point it will be forbidden due to shrinking resources. Instead of seeing your children die like in the first scenario, you will not see children anymore. Not sure which one is the worst prospect!
Either way, alone or all together, immortality is definitely not a good idea. And if it were, life would have certainly invented and adopted it long ago. But since billions of years, evolution and resilience of life on this planet despite all kinds of cataclysms (the latest being humanity itself) is based on a completely different strategy. For a species to survive and evolve, individual beings have to die and be replaced by fresh ones, and for the life itself to continue, species have to evolve and eventually disappear, replaced by ones more fit to changing conditions.
So let's forget about actual immortality. We have many technical means to record and keep alive for as long as possible the memory of those who are gone, if they deserved it. To our transhumanists I would suggest to simply make their lives something worth remembering. It's a proven recipe for the only kind of immortality which is worth it, the one living in our memories.

[This post is available in French here]