[pcrh]

The function of sleep in animals is largely obscure.

One thing we do know for certain is that it is necessary, it is needed in "dumb" animals as well as in you and I. If an animal can't sleep it will eventually die.

I don't think that applies to the activity described in the OP. Does their LLM "die" if it can't perform the function described?

[bayarearefugee]

> Does their LLM "die" if it can't perform the function described?

If you don't periodically clean the context, an LLM effectively goes insane in terms of outputs.

If the LLM were fully controlling a physical system (like a robot body) that contained it the resulting insanity of an ever-growing, never cleaned context would likely result in some sort of death-like event.

[pcrh]

That's probably the closest analogy posted here.

It's still weak, though. An LLM without constant human input is likely more similar to a bicycle that starts to lose its gyroscopic balance as it moves more slowly, a human can however keep a stationary bicycle upright (while riding it).

[adastra22]

There is a lot that is known about sleep. We don't know everything and there are large gaps in our knowledge, but there is also a lot that we do know. And this research explicitly tried to emulate the things we know that sleep does do. Calling it "sleep" is warranted, imho.

[rendx]

"Despite myriad studies, there is still no consensus on why sleep is needed for survival."

https://www.nature.com/articles/d41586-025-00964-w (2025)

[Earw0rm]

Probably because it evolved very early (like before bilateral symmetry, multi layer body cavity, or kidneys early... maybe even before multicellular animals early) and so has been incorporated as an essential pillar into multiple processes layered on top of that fundamental architecture.

[fc417fc802]

You've merely stated observations about the context and the process that led to it. That doesn't in any way answer the question of what it's actually doing that's so essential.

[Earw0rm]

My point is that, in a higher organism, it may be essential to how a lot of their processes function, in that it was infrastructure that already existed at the time those processes were developed, so they were in turn developed to depend upon it.

So "the reason it originally exists" and "what breaks if you take it away" aren't necessarily the same thing.

As with, say, digestion, or an major organ like the liver, it's reasonable to think that it does simple things in simple animals, and more complex things in more complex ones.

Take out an animal's liver, it's not one process that stops working, it's dozens. There's one or two that will kill it quicker, so those are the ones it dies of, but artificial livers are hard to build as they implement so many vital processes.

[fc417fc802]

I don't dispute any of that but it's stating the obvious, it's nothing more than topical conjecture (even if it's almost certainly correct), and (most importantly) it does nothing to answer the question. What essential functions are being performed?

Take your liver example. We can largely answer that same question. I can't off the top of my head but the answer is fairly well established even if incomplete to varying degrees depending on the species.

There is widespread consensus on why a liver is needed for survival whereas there is not for sleep. That's particularly interesting when you consider that sleep is more common across the tree of life than dedicated livers are (at least AFAIK).

[avadodin]

He's saying that it will kill you because some other process has evolved to depend on the same genetic code.

GTAGGA turning into GTACCA may make you sleep 8 fewer hours but also keep you from producing haemoglobin.

It's like leveraging a qsort implementation from your mp3 player to develop your OS scheduling algorithm.

His argument is that there is nothing essential about its apparent function(playing mp3s).

[fc417fc802]

No one here said anything about genetic code.

If he articulated a particular essential process and why it depends on sleep in an incidental manner that might make for a reasonable hypothesis. However it would not refute the earlier (cited) claim that there is no consensus.

As presented without any concrete information about the processes involved it doesn't even qualify as a hypothesis, merely empty handwaving. In context it's even worse, being an entirely baseless contradiction of a claim pulled from a prominent paper.

[jjk166]

It is not necessary to answer the question of what it's doing that is essential to know a subset of what it is doing.

[fc417fc802]

I don't think your response is coherent.

The question was "why is it needed". In context the meaning is clearly to ask what it's doing that's essential and (it follows) why those things are essential.

The subsequent response did not (as you suggest) articulate some subset of nonessential things done during sleep. Rather it rattled off plausible (and widely understood) aspects of the process that could have led to the current situation. Even if it had listed concrete activities that would still not have made for a meaningful answer.

The first clue that something is wrong should be that the linked article is recent and prominent. Thus short a brand new groundbreaking development we can be reasonably certain that a random commenter on the internet will not be sensibly rebutting the claims (and certainly not in the span of ~2 sentences).

[DoctorOetker]

I've always assumed its spontaneous specialization of species: leaving the safety of their nest at those times of day when they are the fittest to occupy a niche.

Once energy conserving "sleep time" exists, the genome can postpone or schedule for activity during these times of day, if it turns out to be more effective somehow.

[crabbone]

I think sleep serves multiple functions. For example, anyone who works out in any-what systematic way knows that sleep is essential for muscle grow. You can't skip on sleep if you want to get fitter. And this probably has very little to do with the more sophisticated functionality of the brain, rather it allows for some process in muscle tissue to happen.

So, whether the LLM "dies" in any sense may or may not be important for what "sleep" is defined to be in this article. It's quite possible that sleep also affects endocrine system in animals or hormones etc... and that's what's causing death, not necessarily anything to do with how brain functions.

[ben_w]

> If an animal can't sleep it will eventually die.

Very few animals fail to eventually die even with as much sleep as they want.

But before death, there is a loss of cognitive function from sleep deprivation, and we observe this too with AI whose context windows get too full.

While we don't know very much about sleep, my understanding is that we do have a long list of things that we do during it, we just don't really understand if sleep is necessary for each of them or simply a convenient opportunity for it.

There's lots of things biology does in response to easy-to-detect proxy signals instead of the real thing they care about: Our sensation of needing to breathe more is based on too much carbonic acid in our blood, not lack of oxygen, which is why in general nobody is allowed in an elevator with a liquid nitrogen dewar; Our natural distaste for incest is based on who we grew up with, not our actual DNA; Get too cold and some people suddenly feel warm and want to (and some do) take all their clothes off even though that would just make them hypothermic even faster.

Being asleep may trigger the things we need to get done, but that doesn't mean sleep is *fundamentally* necessary for the things we need to get done. It could be just that it happens to be the way our biochemistry is wired, and we may find some other way to trigger those things.

The quotation given by djeastm would by my guess for what a dream is, and why we have them. But we don't spend all our time asleep, dreaming. And I'd be the first to say that my guess isn't worth much, as I'm not a brain scientist.

[jyounker]

> Being asleep may trigger the things we need to get done, but that doesn't mean sleep is fundamentally necessary for the things we need to get done. It could be just that it happens to be the way our biochemistry is wired, and we may find some other way to trigger those things.

We now have evidence for REM sleep in spiders(1). Our last common ancestor with spiders predates the development of nervous systems. This strongly suggests that sleep (and specifically REM sleep) serves some function important enough that it has independently evolved in both protostomes and dueterostomes. (And probably multiple times within the protostomes, being present in both cephalopods and jumping spiders.)

There may be some commonality in the origin of the ion channels, but I'll lay money that the requirements for sleep are more of a result of general information processing requirements.

(1)https://www.pnas.org/doi/10.1073/pnas.2204754119

[nextaccountic]

> The function of sleep in animals is largely obscure.

This just obscures the conversation IMO. We know a great deal of functions that sleeping performs. We don't know everything. For some reason this prevents us for using this word in a computing context? What do you think about sleep(1) in Unix?

Also..

> Does their LLM "die" if it can't perform the function described?

what "death" means in the context of a computer program?

[palmotea]

> The function of sleep in animals is largely obscure.

Also, there's different kinds/stages of sleep, which probably perform different functions.

For instance, REM may do something like the GP describes, consolidating memories and processing learning. Deep sleep may do something else (I vaguely recall some stage of sleep is used by neurons to clear certain waste products).

[Windchaser]

I don't think it's necessarily correct to think of sleep in terms of "it is necessary for animals or they will die". It might be more useful to think of it as "it was so useful that animals who slept outcompeted all the animals who didn't".

Meaning: it might just provide a big advantage.

I don't want to overextend and assume that any advantage extends to LLMs. That rest-and-recuperate advantage might also extend to LLM-based AIs. Or maybe not, and the rest-and-recuperate is mainly useful for biology-based organisms. But there is some logic to it.

> The function of sleep in animals is largely obscure.

In my understanding, it's well-understood that sleep is used to consolidate and store long-term memories (amongst other functions, like cell and muscle repair). They've found this memory-consolidation-during-sleep even in relatively simple animals like bees.

[pcrh]

Sleep-like states exist in animals with nervous systems with a complexity above that found in flatworms, even snails sleep. Sleep therefore appears to be an essential characteristic of more complex biological nervous systems, i.e. biological computers, should you care to stretch the analogy. The more complex the nervous system, the greater the requirement for sleep.

What is described in the OP is therefore not a specific characteristic of sleep. It may however be a "useful" rhetorical device.

I do however object to the extensive use of such rhetorical tricks in the conversations that surround LLMs. For example, why does a consumer-grade LLM display "thinking" while it is actually sending data from my computer to some datacentre, processing it, and sending the result back? Equally, why does it output human-emotive phrases such as "sorry" when such computation is revealed to be incorrect?

Such rhetorical tricks, and more, likely underlie to a large degree the popularity of LLMs, despite their actual performance being clearly below what the rhetoric implies.

[palmotea]

> I don't think it's necessarily correct to think of sleep in terms of "it is necessary for animals or they will die". It might be more useful to think of it as "it was so useful that animals who slept outcompeted all the animals who didn't".

You're talking about different things: biological necessity and evolutionary benefit.

You can find out about the former by preventing an animal from sleeping (but otherwise provide all other needed things), and seeing if it will eventually die.

[sillysaurusx]

> You can find out about the former by preventing an animal from sleeping (but otherwise provide all other needed things), and seeing if it will eventually die.

That is actually almost impossible to do. The rat study was as close as we’ve ever come, and it’s still debated whether the rats died due to lack of sleep or some other mechanism, since the autopsy couldn’t confirm a cause of death. (It could have been due to the way the experiment ran, for example, not the lack of sleep.)

[michaelmrose]

What about fatal familial insomnia in humans

[vitamark]

If I remember correctly, fatal insomnia shares most symptoms with other prion diseases (in which there might be no lack of sleep involved), so it's probably the brain damage that causes death, not insomnia itself.

[naasking]

> Does their LLM "die" if it can't perform the function described?

It dies in terms of usefulness if it can't stay up to date with new knowledge. That is, it will no longer be used and thus effectively die off.

[exe34]

LLMs also don't mate, but we can still talk about how they remember or forget things. The meaning of words change. Some of those changes are useful.

[libria]

Is a volcano described as dormant (dormire, literally sleep) also inaccurate and deeply problematic? BTW, it's not anthropomorphized as sleep has existed long before humans.

"Sleep" is just used in their context to describe a non-interactive mode and they didn't lean heavily into zoomorphic - I think you mean - parallels.

You're grinding an axe on a single term. What is your broader hangup with them using the term "sleep"?

> Does their LLM "die" if it can't perform the function described?

We're reaching an age where LMGTFY should now be Let Me LLM That For You. Have you tried asking an LLM this question about the article? I believe it answers it very well.

[sillysaurusx]

> If an animal can't sleep it will eventually die.

That turns out to be un-settled science. No human has ever died from lack of sleep.

People point to “fatal familial insomnia” as a counterexample. But they die to the disease, not the lack of sleep.

In a series of controlled experiments, rats and fruit flies did die from lack of sleep. But no one has yet proven that it holds true for vertebrates except for rats.

In other words, it could be true that “among vertebrates, only rats die of sleep deprivation.”

So “if an animal can’t sleep, it will eventually die” is actually quite hard to prove, and depending on how you look at it, somewhat easy to disprove by the fact that rats and fruit flies were so difficult to kill from sleep depravation alone.

Personally I’m skeptical of the rat study too. Claude amends this:

> What they did not establish: the mechanism. On autopsy, “no anatomical cause of death was identified.” The rats showed weight loss despite eating more, body temperature problems, and skin lesions, but nothing that pointed to a clean cause. So no, they could not say a rat “died from sleep deprivation alone” in the sense of identifying what sleep loss did to the body to kill it. They showed a strong association under tight controls, not a proven causal pathway.

[dijit]

> No human has ever died from lack of sleep.

As far as I understand it, there is a disease that destroys your brain's ability to produce sleep. Once you have it, you suffer total, progressive insomnia and die within roughly 6–18 months. Scientists debate whether it's the underlying brain damage or the sleeplessness itself that causes death, but the two are inseparable in practice, and sleep deprivation is considered the leading candidate.

Separately, the longest anyone has stayed awake under controlled conditions was 11 days, which produced severe cognitive impairment, paranoia, and hallucinations; suggesting the body deteriorates rapidly without sleep.

It's probably not wise to state your original claim as established fact.

[famouswaffles]

Fatal Familial Insomnia is an incredibly rare prion disease that causes widespread neurological destruction. It's not remotely a normal brain that has chosen not to sleep. It's such a highly non-trivial deviation of the brain that we've only identified a few dozen families in the entire planet that suffer from it. At this point, quite a lot of things have already gone wrong in your brain.

There is quite literally no prion disease that isn't fatal.

Sleep does a lot of very important things that we probably wouldn't live long without, but it really is unclear to what extent sleep is necessary for them. If we had enough knowledge, could we trigger all the things sleep does without invoking sleep itself ? Perhaps sleep is just a very convenient mechanism.

[sillysaurusx]

My second paragraph addresses that:

> People point to “fatal familial insomnia” as a counterexample. But they die to the disease, not the lack of sleep.

It’s a prion disease. It’s established fact that they don’t die from the lack of sleep.

[dijit]

Interesting that the scientific debate is settled, because you said so. Researchers who study prion diseases would probably be surprised to hear it.

[sillysaurusx]

Huh? Ask Claude or do some research on the topic if you don’t believe me. A prion disease killing you has nothing whatsoever to do with the lack of sleep. The insomnia is a side effect, not the cause.

Jeez. People here are really stretching to defend their false “we die without sleep” claim.

[chris_wot]

Provide some evidence to back up you assertions. Don't tell someone else to do it for you.

[dijit]

Here's what Claude has to say about our exchange here.. since you asked.

> You're using absence of evidence as evidence of absence — which is a weak foundation when the evidence is genuinely hard to capture. You can't ethically deprive humans of sleep to death in a lab, and FFI affects only a handful of families worldwide.

> On the prion disease specifically: researchers haven't dismissed the role of sleep deprivation they've actively attempted to treat the insomnia in FFI patients on the hypothesis that it contributes to decline. That's not how a field behaves when it considers something a settled, irrelevant symptom.

> More broadly, "no human has ever died from lack of sleep" is an extraordinarily strong claim. To support it you'd need to rule out sleep deprivation as a factor in every candidate case and have a complete understanding of the mechanism. We have neither. The honest position is "we don't know" — not confident assertion in either direction.

[hajile]

They no longer accept world records for not sleeping because the record breakers have universally suffered lifelong cognitive damage.

We know more generally that people who get decreased amount of sleep suffer increased rates of physical and mental health issues.

It is not a very big leap from "causes permanent damage" to "enough permanent damage can cause death" and of course, keeping someone awake until they are hurt or killed is deeply unethical, so even if it could be proven in other species, you'd still be here arguing that 'they aren't humans".

[refulgentis]

It’s a bunch of Claude blather, and I love Claude. Just not worth copying over to HN, because the rush to get to a narrow answer to a narrow question elides the meaningful bits, ex. what does happen during sleep deprivation. Has a “not even wrong” air simply because you’re trying to get to true/false on a narrow question then pushing your research assistant to disavow what you’re quote unquote “skeptical” of.

[sillysaurusx]

This is little more than a fancy way of saying “Nu uh.” Such arguments are hardly convincing.

[refulgentis]

I don't understand this post. I can read it, but I don't understand it.

Why do you think I'm arguing something? Again, smacks of Pauli's not even wrong. You're confusing your headspace with everyone else's and rushed to copy pasta an AI you're browbeating into disavowing things you're skeptical of to...win an argument, I guess? Based on this post? Unclear to me what the argument is, or, if I'm understanding correctly, due to the narrow focus while being self-absorbed.

[burnte]

HIV doesn't kill you, but it creates circumstances where other things will. Sleep is the same. You may not die from lack of sleep, but you die from the things it can cause. Effectively there's no difference.

[sillysaurusx]

I’m shocked by how careless everyone here is about their definitions, and their science. Sleep isn’t the same as HIV. It’s in fact so hard to kill something with a lack of sleep that it’s never once been observed in vertebrates outside of one specific rat study, and that rat study couldn’t conclusively identify sleep as the cause of death.

For something so incredibly difficult to do (die from lack of sleep) it’s frankly crazy that most people here are saying it like it’s fact.

[burnte]

> I’m shocked by how careless everyone here is about their definitions, and their science. Sleep isn’t the same as HIV.

I do not believe this analogy really confused you. No one is saying they're the same and you're well aware of that.

As to the factual nature of the argument, I'll let you argue with Harvard Brain Institute, as I have no interest in this debate. https://brain.harvard.edu/hbi_news/why-severe-sleep-deprivat...

[bulbar]

A knife doesn't kill you, what kills you is the blood you lose after you get stabbed.

Lack of sleep doesn't kill you / does kill you in the same sense.

[nkmnz]

I'd probably kill myself after a couple of days without sleep. Would the lack of sleep be the cause of death or the cause of the cause of death?

[selfsimilar]

Bullets don’t kill you, it’s the bleeding that gets you. Wait, no, it’s not the bleeding since you could just put an IV in, it’s the loss of blood pressure. No wait, it’s not the loss of blood pressure since we can reattach severed limbs that have been at 0/0 for hours. It’s the lack of oxygen to the brain and other vital organs. Bullets definitely don’t kill you /s

[ambicapter]

So? You don't need a proven causal pathway to state that a glass heads towards the ground every time you brush it off a table.

[sillysaurusx]

Scientifically you do, otherwise you can’t claim that lack of sleep was the cause of death. It could be an artifact of how the experiment was run, or any number of other factors.

It’s not a small quibble to point out that the central argument (“animals need sleep or they’ll die”) may be mistaken.