Hacker News Reader

Comment by rusanu | Hacker News Reader

Oxygen[0] by Nick Lane makes a pretty compelling argument why this will not happen. With perfect health you can at best achieve ~120 years age. I think this paper A unifying view of ageing and disease:the double-agent theory[2] covers some of the arguments in the book.

To give a simplified view, the big obstacles are a) a technology capable of repairing damaged mythocondrial material in a living organism and b) a technology capable of repairing neural cells w/o replacing them (that is if you want to preserver 'you', not just your body). That is assuming that our current understanding of senescence[1] is even mildly accurate.

[0] http://www.amazon.com/Oxygen-Molecule-World-Popular-Science/... [1] https://en.wikipedia.org/wiki/Senescence [2] http://www.nick-lane.net/double-agent%20theory.pdf

View on HN

What do you define as "perfect health" when you are made up of cells that keep being regenerated?

Some animals have biological immortality as far as we know. Most however enter senescence after reproduction, probably because evolution optimized for that.

I think that if we sampled people's DNA at 15, and then used a retrovirus every few years to refresh the DNA in the cells, we would solve the biggest issue of random mutations piling up. But this is a long way away. Of course, there may be other processes that build up but a youthful immune system should be able to fight them relatively effectively.

Even so, the chance of death would only be reduced from exponential-exponential to exponential, since the chances of someone living A to B and B to C are independent and therefore multiply.

I'm pretty sure that you can replace a significant number of my neurons without changing "me".

That’s a great question that’s been pondered by philosophers for a while: https://en.wikipedia.org/wiki/Ship_of_Theseus

Here’s a fun video talking about the same thing: https://www.youtube.com/watch?v=nQHBAdShgYI

To the contrary, "you" are constantly changing as your existing neurons reconfigure themselves. Replacing them would have at least the same effect.

What makes you sure? Central nervous system neurons are incapable of regeneration[0], so is anybody's guess what would happen if they did get replaced. And, long term, "significant" has to be "all".

[0] https://en.wikipedia.org/wiki/Neuroregeneration

People can have rather serious strokes that kill large number of neurons without losing their sense of self. Sometimes we remove half the brain

https://en.wikipedia.org/wiki/Hemispherectomy

That gives me confidence that replacing neurons at a rate that counters natural aging does not significantly alter me.

From a Biblical perspective (if you believe that) it isn't possible. Genesis 6:3

Reply on news.ycombinator.com