I call bullshit! And it's not because of the teleological implication you're making - it's because you're overfitting a pattern - limited existence - where you have no data to observe the correctness of your conclusions!

You think you see reasons why an overly long-lived human would encounter difficulties because of limitations you perceive that they'll encounter, but your observation set is so limited that your conjectures must be treated as conjectures, not as solid understanding!

The limitations on learning we observe in older human could easily be due to a huge number of factors, almost all of which are extremely solvable. The one mentioned here, that crystalized intelligence, which is an advantage in some ways becomes a liability in this case - that one is not immediately solvable in my view -

But when I discuss radically increased lifespans for humans, and I discuss it often because I want to see it happen and am already participating in a startup whose success I believe will hasten that effort, I often hear people giving reasons much like yours are reasons why my efforts are not worthwhile. Honestly, seriously, people are using justifications like yours to avoid investing in efforts like mine, and it's maddening to hear such an unsure, ephemeral hypothesis - and I honestly regard the conjectures you've made above to be among the most uncertain hypotheses in history of humankind - to be used as a reason to deprive concrete efforts of concrete investment.

Absolutely maddening, especially because I don't even necessarily disagree, but if the actual pattern for humans is that after, say, 1,000 or 100,000 years, we've got too much cruft as a part of us to continue, we'll never know unless we investigate it, and we can't investigate it if everyone just blindly trusts in silly design pattern hypotheses!!!

Hold on a sec, I'm not at all in the group you think I am in. I've also put the word "design" in between double quotes for a reason; please be a kind reader and re-interpret it the way it was meant to be perceived. Online discussions have a way of erasing subtle nuances, let's try and resist that trend, shall we?

I am 100% for research into radical life extension. I am 100% pissed off by those who oppose (or are indifferent to) this research for whatever reason. I totally hear ya.

But I am also a realist. We have been optimized by evolution for spreading the more successful genetic sequences, nothing more. Once the machine has served that purpose, its subsequent fate is inconsequential. That's been the high level trajectory of the blind optimization process so far, for billions of years.

The human brain is absolutely optimized to peak early and struggle mightily at the game of Spread Your Genes. It's chock-full of subroutines that kick in and help it play the game and hopefully win. Once that's been statistically achieved (by the end of your 20s, according to our default genetic programming), the same subroutines sort of don't care about it anymore and slowly begin to fade out.

That's not to say this is acceptable, or we should just lay down and take it. I've very little doubt that a solution could be engineered to stop and eventually reverse the aging process. But we're unlikely to succeed if we don't acknowledge the challenges that litter the path to this goal.

Assuming you are running on well-maintained hardware (your brain), I don't think there's any set limitation to how well your intellect will function after a long period of time.

We forget. A lot. As a normal course of thinking. And that's OK.

Old habits (good and bad) do die, with a bit of effort, if they aren't being constantly reinforced. If you make it a point to continually refine and improve how you think (trying to disabuse yourself of invalid ideas), then you are setting yourself up for a better future.

To fend off the hysterics which the word 'design' might cause, I'd maybe phrase this as "evolution hasn't optimised us to last longer than ~80-90 years."

I agree that, in keeping with all efficient system structures, we seem to be built so that all of our systems fall in a heap at roughly the same time.