Minimum lifespan for a sapient race

And to clarify I’m not counting something like a Meeseeks. How long an individual lifespan would probably be necessary for a species to develop a civilization?

Edited by ecss on Aug 18th 2023 at 12:37:48 PM

I am not sure that there is a physical reason to expect a correlation. One or two decades, maybe?

How fast does that species learn? A species that can absorb decades of research in an afternoon of reading could theoretically make progress with only a year of life.

Further, if they can quickly and easily spread information around—e.g. via a hive-mind, or even just a "shared memory"—then an individual needn't even survive a given endeavour in order for their work to contribute to the overall technological advancement of the species.

Imagine a species for whom a given project may take a hundred generations—but for whom that doesn't slow things down overmuch, because when one researcher dies, another can take over pretty much immediately, with all of the requisite knowledge.

I think a hivemind is a bit of a cheat because in a hivemind, the "lifespan" is effectively infinite. Sure individuals die but the super-organism of the hivemind does not. No time is lost on developing individual ties or establishing a social order.

The main question of what the minimum lifespan you need to build a civilization depends a bit on what you consider "civilization" though. Establishing farming? Industrial revolution? Space age? Social structures have been immensely helpful in making humans the dominant species, but it doesn't require a lot to consider it a civilization. It also depends a bit on how long it takes for the species to fully develop. We do spend almost 20 years becoming an adult, so for a human-like species the lower limit might be something like 30-40 years. But if you have a species that grows to maturity much faster for some reason, that limit may be lower.

I see what you're saying, but it seems like a valid solution to the question, to my mind.

But, even if we do disqualify hiveminds, the suggestion of merely a "shared memory" still stands, I feel: individuals would have their own personalities and thoughts, but access to knowledge from across the species.

A bit like the knowledge-downloads from The Matrix.

... But hopefully less uncomfortable. :P

Edited by ArsThaumaturgis on Aug 19th 2023 at 11:51:18 AM

That, or the ones holding the memories are mechanical in nature and the species' of flesh and blood's purpose is to maintain, repair, and ensure that the memory-holders remains functioning, tutoring their next generations to continue the work until the "Legion Lexicon" brings them an ultimate salvation.

Less to keep in mind, more focus to life life as well without having to read up on all the records every single time.

Oh it is. I meant more that since the hivemind is effectively immortal, the real answer in that case is that the lifespan is infinite, rather than effectively zero (or irrelevant) for it's constituents.

Ah, I see—I misread you then, and my apologies! In that case I do concur! ^_^

Edited by ArsThaumaturgis on Aug 19th 2023 at 7:47:08 PM

Physical maturation and mental capabilities to learn and retain and pass on knowledge are already mentioned.

Another requirement that may be necessary to think about is length of year/day, the ability to survive other climates without evolutionary advantages such as thick fur for cold climates or tolerating dehydration in the desert.

Why? Many inventions of human civilization were to adapt the environment to our needs or to survive. Concepts such as structural insulation developed to survive cold climates, water pumps and irrigation and wells to survive desert and dry land climates.

Without at least some of those, civilization as we know it today would be impossible for wide swathes of the world.

Edit:

How this relates to how long is the consideration of time. If length of day is gigantic and the species is too slow at developing water resources (even if in terms of basic construction) in a dry environment, then civilization will never emerge in a quick way if at all.

Edited by MajorTom on Aug 19th 2023 at 11:35:06 AM

I think it kind of depends on what your cutoff for civilization is. Human lifespan has increased with time, both in the sense that more people live to an old age and that that old age is much older. A species with a relatively short lifespan would, through better food security, sanitation and healthcare, develop a longer lifespan. In fact, i would argue that species will run into issues where the more advanced they are, the harder it will be to develop more. For relatively low-hanging fruit like we have today it's not that bad (although i would note we spend ~20 years of our lives to develop), but the bigger and more interconnected various fields become the more and more time and effort you would have to put into pushing the boundaries further.

For a sapient species without "cheats" like genetic memory, what you need, fundamentally, is an apprenticeship cycle. The species must live long enough to:

• Learn from a master (Apprentice)

• Be independent for a time learning new things (Journeyman)

• Take on an apprentice to teach those things (Master)

I can't give a true minimum number based on anything more than a haunch, but I feel that 15 years is probably the limit. In fact, 20 years might be a better limit:

• Five years to mature enough to meaningfully learn.

• Five years to learn

• Five years to discover

• Five years to teach

Even this implies a species that matures faster than humans do, and their technological growth would probably be significantly stunted by their short lifespans.

Edited by Protagonist506 on Aug 20th 2023 at 12:06:18 PM

TBH i'm still somewhat stuck on the idea of what we consider civilization here. Developing something like farming implies that you could be around long enough to see seeds be sown, and also harvested. It would, after all, be nigh-impossible to understand the utility of farming if you had to be told by your great-great-great-grandfather that they once sowed seeds last year. If we consider the development of farming as the start of civilization, then that would probably put the minimum at something like a year after adulthood -whatever that year is in real length-. It's more tricky if you deal with extremely long days or tidally locked planets since any sense of time would be vastly different.

But if you consider civilization to be something like kingdoms, empires or nations (and not merely poorly centralized tribes of people) that would require the ability to establish traditions and laws and precedents. It would be exceptionally hard to do if everyone died rapidly, though i also don't see a hard cut-off. Like imagine a tribe trying to organize farming. If crops take a cycle of a year, how could you properly organize the tribe to prepare for the next year if they all died before that. Adults who never saw the seeding process would have to sow and adults that never saw the reaping process would have to reap. You would need a lifespan of years before you could develop farming enough to have enough excess for cities and enough cities for kingdoms.

Though this also brings me back to the previous element: isn't it true that a species with increasingly shorter lifespan would have more difficulty establishing a civilization, but at the same time there's no true hard limit on it? Even if these people acted more or less by chance, eventually you would get a chain of events leading to sufficient organization to guard the achieved knowledge, which in turn would require the next chain of events to lead to greater organization etc. It would be difficult, but farming in our world evolved many times. Civilization could form and regress perhaps thousands or millions of times. All that matters is that for some time, it exists, even if for a short-lived species that's unlikely.

You could probably shave that down to a total of "a bit over a year" by virtue of having the young grow up on the farms.

They'd thus watch and have impressed upon them the importance of the sowing in their youth, grow up to harvest, and in their old age sow in turn as the next generation watches...

(I say "a bit over" primarily on the assumption that—as with humans—this species would have a period at the start of their lives at which they're not yet ready to observe and take on significant activities.)

Well that's the other element i'm kind of stuck on, but the post was long enough. What's the minimum development time of a sapient species? Humans kind of suck because our heads are too big and so we spend a lot of time outside the body before we're truly fully grown. We then spend over 10 years developing the body and brain. But if we had a species that could live birth without issues, would that go away? if pregnancies didn't have these issues, would we grow up faster?

Because i suspect there would be very good reasons why it takes so long and i strongly doubt we could just fix that otherwise. Like, a smaller species would still need a substantial brain, and the relative size would still make live births difficult. A bigger species might have more ease with births and development but the greater size may demand longer development. I don't really see where the optimum lies.

Would an egg-laying species, for example, be vastly superior? I kind of doubt it, i would expect egg-laying species to be incredibly more dominant then.

I suspect that it's a mixture of factors, and it's hard to tell just what solutions might potentially exist.

For example, (relatively-intelligent) species on our planet tend to rely on brains, and primarily on singular brains—but perhaps species on other planets might develop different arrangements. Maybe they use some other structure, or have their equivalent structures distributed more broadly around their bodies.

But even if one bypasses the "head-size at birth" issue, there's still the question of how quickly they might develop thereafter. We... don't really have much to go on there—and again, the answer may depend in part on aspects that might be different in a species from a completely different lineage.

Not necessarily: it may be that some local -minimum or -maximum of selection pressure resulted in live-birth being favoured on our planet.

It may be that, under a different set of pressures, egg-birth might find an opportunity to be applied to intelligent life that it hasn't had here.

I'd say 20-30 years would be a good minimum, mainly due to corvids. It's estimated that crows and possibly ravens have intelligence comparable to a seven year old child yet they usually only have a lifespan around 20 years. I'd argue that a longer lifespan may be more beneficial overall for a sapient species due to better accumulation of knowledge but one could argue that a shorter lived species may have better memory retention and faster learning ability.

Well human lifespans have increased over time with better medicine, farming, sanitation. If a corvid species with an average lifespan of 20 developed modern infrastructure it wouldn't necessarily be weird to see them grow to 50 or 60.

So the main concern is simply crossing that gap in the first place.

I'm not sure that lifespan correlates that strongly with intelligence. Thus I'm not sure of how one might take the example of corvids to establish a minimum lifespan for a sentient species...

Could you expand on your logic there, please?

With intelligence and lifespan, the big thing is that you need to be able to live long enough to actually learn things, otherwise there's not too much of a point.

However, I will note that there are some extremely intelligent species that are quite short-lived. Cephalopods, for example, are brilliant but only live for 3 years or so.

This does, however, really diminish their potential for the above reason.

Intelligence and Knowledge are two different things.

Indeed.

If I recall correctly, even humans of only a handful of years can be remarkably intelligent—finding novel and creative solutions to problems, for example—but of course have very little knowledge as of yet.

It's why i find intelligence to be such a fuzzy and useless concept. Seems like every year there's some sort of "X is smarter than we assumed" article or "creature we thought was dumb and dead inside has rich social life". Not to mention that there are plenty of people who get called brilliant and visionary who turn out to be lying frauds.

It seems to me that, as a whole, our grasp on what exactly intelligence is supposed to be sucks. The hardest, most unaltered conclusion we seem to be able to draw (and do so consistently) is that some are better at specific types of puzzles/actions/tests than others.

Oh, very much so I do believe! As far as I can tell, "intelligence" is a greatly multifarious thing.

Indeed, even looking at a single species (humanity), one person can be absolutely brilliant at one thing but poor at something else, while another person can be absolutely brilliant at that something else, middling at the first thing, and poor at a third!

The shortest lifespan for a sapient race I can think of is the Rustbloods of Homestuck (technically a subgroup of a larger race, but still), who live for a minimum lifespan of roughly a dozen sweeps. Here on Earth, that's around 26 years.

I'm going to agree with other posters here and say that the minimum lifespan of a sapient race is somewhere in the twenties. The average human lifespan was around 30 a few hundred years ago.

Edited by HunterGr33n on Sep 24th 2023 at 10:24:40 AM