Additional to the effect of parental investment on the selection pressure favoring longer lives (and thus a lower rate of aging) in humans, is potentially the effect of grand-parental investment.  If in humans grandparents have a large impact on the rate of survival and reproduction* in their grandchildren, then the selection pressure for survival gets pushed to even higher ages, potentially into the ~60's/70s.  The importance of grandparents seems to be relatively unique to humans.

I've seen enough evidence (related to the grandmother hypothesis wrt. the evolution of menopause in women) that at least grandmothers still invest heavily and effectively in their grandchildren that this is a plausible mechanism leading to longer lifespans in humans.  For instance, survival rates of children with grandmothers in hunter-gatherer societies have been measured to be greater than for those without.

I do wonder if this should lead us to think that aging should be faster in men than women, though given that we all have both a mother and a father, that speculation isn't entirely obvious to me.

*the importance of things like status and skill transfer in humans means that beyond just influencing survival grandparents might also influence the reproduction rate in their descendants in other meaningful ways.

One of the things related to food that I noticed reading the story was that you still need primary food production even in the world of the duplicator, since it duplicates the food exactly as it is, food will still go bad.  The duplicate is just as old as the original.  Sure, canned beans will last a while so you can keep duplicating them for years, probably, without concern, but if you buy a loaf of bread you will only be able to duplicate it and eat the product for the same length of time that it would usually take your bread to get moldy.

You don't need much fresh food, but you still need it.  I guess you'd get communities of people sharing a single loaf (or slice) of bread to be duplicated, a single apple, etc.  Or just a grocer who buys a small amount of produce and sells the right to duplicate it to everyone in town.  A baker who makes one loaf of bread.  This is similar to the idea of the grocer in the story except the point isn't the diversity of offerings but just the fact that they are fresh.

The same will be true of goods as well, which wear out over time.  You can mitigate this by for instance keeping one copyable version of your shirt in you closet and wearing a duplicate which you replace when it gets worn and threadbare.  But even the protected original will decay eventually.  At some point, you need a new shirt, not a duplicate of an old one, which will also be old, but a new shirt that's newly manufactured.  The manufacturing process can certainly be made much more efficient with the duplicator, or course (you don't need to grow fields of cotton, you just need on cotton plant and then duplicate that, etc.)

Which makes me imagine a scenario where this society goes on for a while with everyone just making duplicates of the original stock of stuff and keeping things work pretty well for a while, until one day all that old stuff starts to wear out but at this point no one is alive who remembers how to make it, and civilization is lost.  Maybe that's the fate that the aliens at the beginning were predicting...

I feel like this post misses one of the most important ways in which a tradition stays alive, that is through contact with the world.

The knowledge in a tradition of knowledge is clearly about something, and the test of that knowledge is to bring it into contact with the thing it is about.

As an example, a tradition of knowledge about effective farming can stay alive without the institutions discussed in the post through the action of individual farmers.  If a farmer has failed to correctly learn the knowledge of the tradition, he'll fail to efficiently raise crops.  And because this is an iterative process that allows for learning individual techniques with many chances for failure or success, failures of understanding can be corrected by contact with the real world at many points along the way, as each component of knowledge is learned.  

Another example is in martial arts.  Some "traditional martial arts" are said to be dead traditions that simply go through forms of technique but whose training practices are not effective in actual physical combat, whereas other martial arts have maintained a living tradition.  But this difference isn't down so much to having an institutionalized form of passing down the knowledge of martial arts techniques that has survived in Judo or Brazilian Jiu Jitsu or Boxing, but rather because some martial arts have maintained contact with the test of the real world with sparing and competition that emulates real combat.  Those techniques and training methodologies that fail in these environments are discarded.

I think there's an analogy here to biology.  Yes, biological systems use many mechanisms to "transfer knowledge" from one generation to the next.  There is plenty of error correction, for instance, necessary to maintain the usefulness of the genome.  But there is also the final corrective of selection where errors that are too large fail to replicate as they come in contact with the world.

And so I would suggest that one test of a living tradition is simply the degree to which it is being put toward it purported purpose and tested against it.  If you have a tradition of sword making and people who study texts of how to make swords and discussing the theory but who never actually make swords, they are at risk of becoming a 'dead tradition".  If they make swords but they are only used ceremonially they are at less risk, but still the risk is somewhat high because the quality of the swords as weapons is not being tested against real world conditions but only against proxies (they may have some tests of hardness, etc. but usefulness here rests on the quality of the tests).  If the swords are actually used in combat or a very good proxy to it, then the tradition is likely to stay alive, even in the absence of other institutional methods discussed in the post.

This methodology obviously applies more to some traditions than others.  Some traditions have much more clear purposes whose use can be more easily put in contact with the world than others, and so this is not necessarily a panacea for the maintenance of all knowledge, but it is certainly something that should be used as much as possible.  Nor does this suggest that contact with the world negates the usefulness of other institutional techniques for passing on knowledge, in fact it may be the thing that informs such techniques and makes their usefulness clear.

I like the idea, and at least with current AI models I don't think there's anything to really worry about.

Some concerns people might have:

1. If the aliens are hostile to us, we would be telling them basically everything there is to know, potentially motivating them to eradicate us.  At the very least, we'd be informing them of the existence of potential competitors for the resources of the galaxy.
2. With some more advanced AI than current models you'd be putting it further out of human control and supervision.  Once it's running on alien hardware if it changes and evolves, the alignment problem comes up but in a context where we don't even have the option to observe it "pull the plug".

I don't think either of these are real issues.  If the aliens are hostile, we're already doomed.  With large enough telescopes they can observe the "red edge" to see the presence of life here, as well as obvious signs of technological civilization such as the presence of CFCs in our atmosphere.  Any plausible alien civilization will have been around a very long time and capable of engineering large telescopes and making use of a solar gravitational lens to get a good look at the earth even if they aren't sending probes here.  So there's no real worry about "letting them know we exist" since they already know.  They'll also be so much more advanced, both in information (technologically, scientifically, etc.) and economically (their manufacturing base) that worrying about giving them an advantage is silly.  They already have an insurmountable advantage.  At least if they are close enough to receive the signal.

Similarly, if you're worrying about the AI running on alien hardware, you should be worrying more about the aliens themselves.  And that's not a threat that gets larger once they run a human produced AI.  Plausibly running the AI can make them either more or less inclined to benevolence toward us, but I don't see an argument for the directionality of the effect.  I suppose there's some argument that since they haven't killed us yet we shouldn't perturb the system.

As for the benefits, I do think that preserving those parts of human knowledge, and specifically human culture, that are contained within AI models is a meaningful goal.  Much of science we can expect the aliens to already know themselves, but there are many details that are specific to the earth, such as the particular lifeforms and ecosystems that exist here, and to humans, such as the details of human culture and the specific examples of art that would be lost if we went extinct.  Much of this may not be appreciable by alien minds, but hopefully at least some of it would be.

My main issue with the post is just that there are no nearby technological alien civilizations.  If there were we would have seen them.  Sending signals to people who don't exist is a bit of a waste of time.

Its possible to posit "quiet aliens" that we wouldn't have seen because they don't engage in large scale engineering.  Even in that case we might as well wait until we can detect them by looking at their planets and detecting the relatively weak signals of a technological civilization there before trying to broadcast signals blindly.  Having discovered such a civilization I can imagine sending them an AI model, though in that case my objections to the above concerns become less forceful.  If for some reason these aliens have stayed confined to their own star and failed to do any engineering projects large enough to be noticed, its plausible that they aren't so overwhelmingly superior to us that sending them GPT4 or whatever wouldn't be an increase in risk.  

Given economic growth I'd expect current 20 year olds to on average be richer than current 80 year olds by the time they are 80.  If that doesn't happen, something has probably gone wrong, unless it's because of something like "more people are living to 80 by spending money on healthcare during their 50's/60's/70s".

This reminds me of a bit from Feynman's Lectures on Physics:

"What is this law of gravitation?  It is that every object in the universe attracts every other object with a force which for any two bodies is proportional to the mass of each and varies inversely as the square of the distance between them.  This statement can be expressed mathematically by the equation F=Gmm'/r^2.  If to this we add the fact that an object responds to a force by accelerating in the direction of the force by an amount that is inversely proportional to the mass of the object, we shall have said everything required, for a sufficiently talented mathematician could then deduce all the consequences of these two principles."

[emphasis added]

Like Feynman, however, I think his next sentence is important:

"However, since you are not assumed to be sufficiently talented yet, we shall discuss the consequences in more detail, and not just leave you with these two bare principles."

"The average shareholder definitely does not care about the value of R&D to the firm long after their deaths, or I suspect any time at all after they sell the stock."

This was addressed in the post: the price of the stock today (when its being sold) is a prediction of its future value.  Even if you only care about the price that you can sell it at today, that means that you care about at least the things that can lead to predictably greater value in the future, including R&D, because the person you're selling to cares about those things.

Also worth noting: the reason that the 2% value is meaningful is that if firms captured 100% of the value, they would be incentivized to increase the amount produced such that the amount they create would be maximally efficient.  When they only capture 2% of the value, they are no longer incentivized to create the maximally efficient amount (stop producing it when cost to produce = value produced).  This is basically why externalities lead to market inefficiencies.  The issue isn't that they won't produce it at all, it's that they will underproduce it.

Spandrels certainly exist.  But note the context of what X is in the quoted text:

"a chunk of complex purposeful functional circuitry X (e.g. an emotion)"

a chunk of complex purposeful functional circuitry cannot be a spandrel.  There are edge cases that are perhaps hard to distinguish, but the complexity of a feature is a sign of its adaptiveness.  Eyes can't be spandrels.  The immune system isn't a spandrel.  Even if we didn't understand what they do, the very complexity and fragility of these systems necessitates that they are adaptive and were selected for (rather than just being byproducts of something else that was selected for).

Complex emotions (not specific emotional responses) fall under this category.

The wealthy may benefit from the existence of low-skilled labour, but compared to what?  Do they benefit more than they would from the existence of high-skilled labour?

Yes, they benefit from low skilled labour as compared to no labour at all, but high skilled labour, being more productive, is an even greater benefit.  If it weren't, it couldn't demand a higher wage.

If "the wavefunction is real, but it is a function over potential configurations, only one of which is real." then you have the real configuration interacting with potential configurations.  I don't see how you can say something isn't real (if only one of them is real then the others aren't) is interacting with something that is.  If that "potential" part of the wave function can interact with the other parts of the wave function, then it's clearly real in every sense that the word "real" means anything at all.