One possible issue with radically increased lifespan

If your civilization expands at a cubic rate through the universe, you can have one factor of linear growth for population (each couple of 2 has exactly 2 children when they're 20, then stop reproducing) and one factor of quadratic growth for minds (your mind can go as size N squared with time N). This can continue until the accelerating expansion of the universe places any other galaxies beyond our reach, at which point some unimaginably huge superintelligent minds will, billions of years later, have to face some unpleasant problems, assuming physics-as-we-know-it cannot be dodged, worked around, or exploited.

Meanwhile, PARTY ON THE OTHER SIDE OF THE MILKY WAY! WOO!

Seriously, why is this post being downvoted? It's a legit question and the OP isn't making any huge mistakes or drawing any stupid conclusions. He's just stating some confusion and asking for links.

I actually feel pretty mad about this.

This question shouldn't be being downvoted as much as it is- it is a legitimate question although would probably go better in its own set in the open thread rather than a discussion section.

Yes, this has been discussed a fair bit- the main argument in most transhumanist circles when this comes up is that everyone will get the benefits and that birth rates will go down accordingly (possibly by enforcement). In that regard, there's a fair bit of data that humans birth rates go down naturally as lifespan goes up. There are other responses but this is the most common. It is important to realize that it is unlikely that this issue will need to be seriously addressed for a long way off.

A lot of people seem to be shrugging this question off, saying basically, "Transhuman minds are ineffable, we can't imagine what they would do." If we have some kind of AI god that rapidly takes over the world after a hard takeoff, then I think that logic basically applies. The world after that point will reflect the values implemented into the AI god.

Robin Hanson has described a different scenario, that I take somewhat more seriously than the AI god scenario.

This long competition has not selected a few idle gods using vast powers to indulge arbitrary whims, or solar system-sized Matrioshka Brains. Instead, frontier life is as hard and tough as the lives of most wild plants and animals nowadays, and of most subsistence-level humans through history. These hard-life descendants, whom we will call “colonists,” can still find value, nobility, and happiness in their lives. For them, their tough competitive life is just the “way things are” and have long been.

Hanson is describing a return to the Malthusian condition that has defined life since the beginning. The assumptions seem fairly strong to me:

1. Competition won't cease.
2. The darwinian drive to reproduce will remain (because it is adaptive).
3. Resources are functionally limited, there is only so much usable energy.
4. Life will be hard, there will be lots of people "starving" (e.g. not being able to access enough energy to keep functioning, or not being able to buy replacement parts/server space) at the margins, as it is in the natural environment.

This reminds me. An interesting question is, assuming constant mass/person, how long until the speed of light becomes a limiting factor? I.e. given a fixed growth rate, at what total population would the colonization speed be approaching the speed of light just to keep the # humans per cubic parsec of space constant? It is clear that this will happen at some point, given the assumptions of constant birth rate and constant body mass, because the volume of colonized space only grows as time cubed, while the population grows exponentially.

Here is a back-of-the-envelope stab at it. I have not googled it beforehand, because it's fun to do one's own estimate.

Assume 1 habitable planet (10^10 people) per cubic light year, the total colonized number of planets ~ #years^3 after the onset of interstellar travel at near light speed. (I am not accounting for the relativistic time dilation, though the correction should be small, since only a minority of people are in-flight at any given time.) I'm ignoring the factors of the order of 1, such as 4 pi/3 for the volume of a sphere.

Assume 0.1%/year growth rate. This is about 1/20 of the current birth rate. Total number of occupied planets = 1.001^(#years).

The two numbers become comparable after about 30,000 years. This is less than one third of the size of the Milky Way galaxy (in light years). After that, the population growth will be limited by the known physical laws, long before other galaxies are explored.

The fertility rate is far more important than mortality. You can calculate for yourself that even if humans were immortal, an average fertility below 1 child per parent does not lead to exponential population growth, while average fertility above 1 child per parent means exponential growth even if people keep dying at seventy.

What makes you think we have meaningful opinions to share on the options available to beings that are pushing the carrying capacity of the galaxy?

I think It's a biggish problem to solve.

The first thing that makes it easier is that I see no reason we ought to increase the number of people very much. I think N billion is enough of a party already. Once we all know each other, maybe we can talk about making more. (for the people who are still alive)

Of course that doesn't make the problem go away. If we want to grow as people continuously, we will eventually hit limits. Especially since we might decide that exponential growth is the only acceptable thing.

We might have to accept that there is a non-infinite amount of utility in the universe. That's no reason to give up tho. We should still make sure we at least hit the maximum possible.

See the fun theory sequence specifically this one for exploration of these issues.

It is unlikely that society will ever neatly divide into "haves" and "have nots"- be suspicious of sharp divisions. There should be lots of boundary cases, and probably a smooth gradient.

The primary question for answering these sorts of questions, I think, is whether modification to existing agents is more or less effective than modification to new agents. It seems more likely to me that genetic engineering can radically increase human lifespans than interventions in already developed humans- and if that's the case, then there won't really be immortal elites because the younger generation will always have rosier prospects than the older generation (unless a cap is reached, of course). Currently, we would expect a 200 year old programmer to run circles around a 20 year old programmer, because experience is really valuable. But if the 20 year old has 10 generations of intelligence boosts that the 200 year old can't get, then the 20 year old is probably going to win- especially if one of those boosts is easier experience transfer!

My essay on this (go to the original article to see the hyperclicks to some of the references, as I'm too lazy to copy them here)

One of the most common objections against the prospect of radical life extension (RLE) is that of overpopulation. Suppose everyone got to enjoy from an eternal physical youth, free from age-related decay. No doubt people would want to have children regardless. With far more births than deaths, wouldn't the Earth quickly become overpopulated?

There are at least two possible ways of avoiding this fate. The first is simply having children later. Even if nobody died of aging, there would still be diseases, accidents and murders. People who've looked at the statistics estimate that with no age-related death, people would on average live to be a thousand before meeting their fate in some way. Theoretically, if everyone just waited to be a thousand before having any kids, then population growth would remain on the same level as it is today.

Of course, this is completely unrealistic. Most people aren't going to wait until they are a thousand to have kids. But they might still have them considerably later than they do now. The average age for having your first child has already gone up as lifespans have grown. If you're going to live for a thousand years, why rush with having kids as soon as possible?

Currently there is (at least for women) an effective maximum cap on how high the age for first childbirth can grow, since once a mother's age grows beyond 35 or so, the probability for birth defects goes up radically. However, current reproductive technology has already made pregnancies over the age of 50 a real possibility. At the moment, this frequently requires egg donation, but a rudimentary ability to produce eggs from stem cells may not be that far away, certainly a lot closer than RLE. By the point that we have RLE, we'll likely also have the ability to produce new sperm and eggs from a person's own cells. Combined with an overall better condition of the body brought about by RLE, this seems like it could increase the maximum age for pregnancy indefinitely. With that, the average age for a first birth going up at least a couple of decades doesn't seem all that unrealistic.

Besides the average age for having kids going up, there's the possibility of larger family groups. Must we necessarily have a norm for children being the kids of exactly two adults? As a personal example, my best friend has a daughter who's two years old right now. I've been over there helping take care of the girl a lot, enough to make me feel like she's part of my family as well. Even if I never had children of my own, I already feel something resembling the feelings related to having a child of your own. In addition to growing attached to the children of your close friends, polyamory is also gradually becoming more common and accepted. With romantic relationships involving more than two people we also get children with more than two parent-like figures. Many have a strong desire to pass on their genes, something which can be helped with e.g. the recent creation of 3-parent human embryos.

So with both the prospect of having kids later and a child having more than two parents, I really don't think that the population problem is as hard to solve as some people make it out to be. It should also be noted that it's not like scientists are going to develop RLE one day, and then the next, blam, everyone lives forever. Rather, the technology will be developed in stages. In the early stages, there are going to be a lot of people who have grown far too frail to be helped, and it might take a long time before we hit acturial escape velocity, so there might simply be an e.g. 10-year bump on people's lifespan and then 20 years could pass before the next major breakthrough.

The treatments may also not be affordable for everyone at first, though it needs to be noted that governments will have a huge incentive to subsidize the treatements for everyone to reduce the healthcare costs of the elderly and to push back the age for retirement. A 2006 article in The Scientist argues that simply slowing aging by seven years would produce large enough of an economic benefit to justify the US investing three billion dollars annually to this research. The commonly heard "but only the rich could live forever" argument against RLE does not, I feel, take into account the actual economic realities (amusingly enough, as its supporters no doubt think they're the economically realistic ones).

So we're going to get a slowly and gradually lengthening average lifespan, which at first probably won't do much more than reverse the population decline that will hit a lot of Western countries soon. The replenishment rate required to keep a population stable is about 2.1 children per woman. The average fertility rate in a lot of industrialized countries is well below this - for instance, 1.58 in Canada, 1.42 in Germany, 1.32 in Italy, 1.20 in Japan and 1.04 in Hong Kong. The EU average is 1.51. Yes, in a lot of poor countries the figures are considerably higher - Niger tops the chart with 7.68 children per woman - but even then the overall world population growth is projected to start declining around 2050 or so.

To give a sense of proportion: suppose that tomorrow, we developed literal immortality and made it instantly available for everyone, so that the death rate would drop to zero in a day, with no adjustment to the birth rate. Even if this completely unrealistic scenario were to take place, the overall US population growth would still only be about half of what it was during the height of the 1950s baby boom! Even in such a completely, utterly unrealistic scenario, it would still take around 53 years for the US population to double - assuming no compensating drop in birth rates in that whole time.

We've adapted to increasing lifespans before. Between 1950 and 1990, the percentage of population over 65 almost doubled in Sweden, going from 10.3 to 18.1. (In the United Kingdom it went up from 10.7 to 15.2, in the US from 8.1 to 12.6, and in the more-developed countries overall it went from 7.6 to 12.1.) The beauty of economics is that like all resource consumption, having children is a self-regulating mechanism: if a growing population really does exert a heavy strain on resources, then it will become more expensive to have children, and people will have less of them. The exception is in the less industrialized countries where children are still a net economic benefit for their parents and not a cost, but most of the world is industrializing quickly. Over the last fifty years, the gaps between the rich and poor have gotten smaller and smaller, to the point where people are calling the whole concept of a first world/third world divide a myth. I see no reason to presume that radical life extension and indefinite youths would pose us any problems that we couldn't handle, at least not on the overpopulation front.

Of course, this presumes that we'll remain as basically biological entities. If we develop uploading and the ability to copy minds at will, well... that's a different kettle of fish, with the various evolutionary dynamics involved in that being a much larger potential problem. And of course, if we get uploading, we're probably close to AI and a full-scale intelligence explosion, with all the issues that that involves.

I decided a while back that the next time there's a LW census, I'm going to suggest adding a question like this: "Ceteris NOT being paribus, if you could make all the people in the world invulnerable to diseases, cellular degeneration and similar aging-related problems by pushing a button, would you push it?" I would be very interested in those results.

How would this be achieved? Somehow limiting lifespan, or children, assuming it's available to a majority? Or would this lead to a genespliced, technologically augmented and essentially immortal elite that the poor, unaugmented ones would have no chance of measuring up to?

Limiting lifespan is a time-buying measure at best, and an ineffective one at that; we already have severely limited lifespans, and that hasn't worked out all that shiny from the sustainability standpoint.

The technological elite scenario seems very likely unless there are other radical advances; having the tech to produce biological immortality isn't the same as being able to provide that service to everyone. As things stand, large swaths of the world still can't even get their hands on simple vaccines, and shipping those across the world is a hell of a lot simpler than genesplicing people. And even if it was as simple as shipping X cans of immortality/enhancement pills to all corners of the world, you'd still have on your hands all the luddites raised to believe that genetic engineering and eternal life are sins against whatever.

The novels Red Mars, Green Mars and Blue Mars by Kim Stanley Robinson bring up this question and proposes an answer, offered here in a simple rot13.com cypher for those who haven't read the books yet.

Gubfr jub erprvir gur ybatrivgl gerngzrag ner fgrevyvmrq ng gur fnzr gvzr.

To me, the real turning point is if and when we learn how to precisely control our personalities - in short, reengineering human nature itself. Of course there's the nature vs nurture matter in this, not to mention all the potential factors than even go into a personality, let alone alter it. But I'm 100% against uncontrolled transhumanism, or even mere unregulated genetic modification or augmentation.

Though, let's suppose there was a way to correct obviously harmful behaviorial defects with at least a partial genetic basis, particularly behavior every society would see as egregiously harmful, and especially criminal (supposedly anti-social personality disorder- such as psychopathy - is one of these). Would the prospect of even reducing that behavior be worth it?