Comment by reasonattlm | Hacker News Reader

Comment by reasonattlm | Hacker News Reader

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So you fix brain plasticity as well. The point of the exercise is identify and revert changes, and loss of synaptic/neural plasticity with age is well known and well studied already.

As to population growth, even putting aside the point that Malthusian predictions have always been wrong, and that there is more than enough food production to feed everyone in the world going forward for even quite large increases in population:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3192186/

"This study explores different demographic scenarios and population projections, in order to clarify what could be the demographic consequences of a successful biomedical war on aging. A general conclusion of this study is that population changes are surprisingly slow in their response to a dramatic life extension. For example, we applied the cohort-component method of population projections to 2005 Swedish population for several scenarios of life extension and a fertility schedule observed in 2005. Even for very long 100-year projection horizon, with the most radical life extension scenario (assuming no aging at all after age 60), the total population increases by 22% only (from 9.1 to 11.0 million)."

That'd certainly be ideal, but seems like a more difficult problem which would probably take longer to solve. So my concern would be old, healthy bodies hitting the market without plastic minds. The lag time before brain plasticity breakthroughs is still a problem.

And the issue I'm referring to with food production is the order and distribution of the diffusion of the technology. In Europe, the agricultural revolution preceded breakthroughs in medical technology, and it worked out great. However, the rate of diffusion of medical technology to the east was greater than the diffusion of agricultural technology, which is what caused catastrophic results. Yes, they could have produced enough food, but because the rate of diffusion of the technologies was different, they didn't. We should apply this historical lesson.

In Tragedy and Hope, Carroll Quigley argues:

> importation of an element of material culture from one society to another is helpful to the importing society in the long run only if it is a) productive, b) can be made within the society itself, and c) can be fitted into the nonmaterial culture of the importing society without demoralizing it.

For longevity technology, a) is perhaps true but it's not clear that b) and c) would be for most societies. There's a calculus here worth getting right, otherwise longevity technology could end up doing more harm than good.

Until we solve the problem of entropy(doubtful), we'll have to decide between children and old people.

Not in the near future, as long as we also get effective space travel...

Cool, so we just have to crack the light barrier, too, while we're at it. No problem!

Not at all. Generation ships, suspended animation, there are plenty of other, more possible options than superluminal travel.

Immortality + reproduction means population rate expands at a blistering pace. You cannot build generation ships big enough, and you will fill up every habitable scrap of the solar system, including artificial habitats.

If there is no upper limit on population growth, you also need no upper limit on your rate of expansion.

Suspended animation could work, but now you've just admitted that you're putting a limit on reproduction, but even that ends when those people wake up and arrive somewhere.

Even allowing all that, "we'll solve this unsolved problem by solving another unsolved problem!" does not inspire a lot of confidence.

You're running afoul of the pitfalls of static analysis. Humans don't have an immutable reproduction rate of X% every Y years.

Immortality will reduce reproduction rates intrinsically; 500 years ago it was common to be married off and breeding before you were 15, now you're 'having kids young' if you start before 25, how long will people wait when they live 100s of years?.

Improving global standards of education and quality of living also slow down reproduction. Countries scoring highest in both of these metrics are often fairly stable in population, some even depend on immigration to maintain current levels.

Residual growth after these two factors are taken into account is low enough that the odd colonisation attempt or newly built orbital habitat will be ample space. And this is without even considering that we could end up living as uploads in virtual worlds long before these things become possible.

That doesn't solve the problem. All you do is move the problem beyond our star.

Entropy is still increasing.

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