6 ms·

If true, and complex life evolved more than once on the same planet, then it is much less likely as a strong candidate for the great filter [1]. So, very rough

If true, and complex life evolved more than once on the same planet, then it is much less likely as a strong candidate for the great filter [1]. So, very roughly, either life is hard to get started at all (but life started about as soon as possible on earth), intelligence is hard to evolve (although we see many species with intelligent behaviour, if not at human level), or it's in our future (that intelligent life tends to destroy itself). [1] https://en.m.wikipedia.org/wiki/Great_Filter https://en.m.wikipedia.org/wiki/Great_Filter

bostonwalker 2y ago
The evolutionary transition from single-celled to multicellular life has actually been repeatedly accomplished in vitro [1]. So highly unlikely to be a Great Filter. [1] https://archive.ph/1yCVn https://archive.ph/1yCVn
- sigmoid10 2y ago
  The study in the article suggests that these early multicellular organisms failed to take hold. So there was probably something needed that was missing. And it still took billions of years for complex live to emerge, whereas single celled life appeared almost immediately once the earth cooled down enough to have liquid water. Whether it took two billion years or 3.5 doesn't matter so much when you think of it as a potential filter.
api 2y ago
There are so many more possibilities. The entire topic of the Fermi paradox is a massive tower of assumptions and hidden variables for which we have no information. We don’t even know the paradox is real since we haven’t explored our own solar system enough to rule out aliens or artifacts of their visits in our back yard, nor can we rule out advanced observers intentionally not revealing themselves for any number of rational reasons. There could be an abandoned underground alien base on the Moon and we’d have no clue. We have barely gone anywhere. If we hit, say, the level of development in The Expanse and still find nothing (no protomolecule haha) then maybe we can say there is definitely a paradox. There’s also the assumption that there is a single discrete big and dramatic great filter. That’s the Hollywood version. In reality there could just be a continuous probability of failure due to any number of events whether endogenous or external spread across billions of years that amounts to a great filter. The probability per day of “biosphere failure” or some other condition that dooms a potential spacefaring intelligence doesn’t need to be high to amount to a probability near 1.0 over geological time scales. Let’s say given we are sending our probes and capsules we are probably at least 50% of the way there. If the cumulative great filter were near 1.0 probability of failure this would imply a 50/50 probability of our success. Those are of course made up round numbers just to illustrate how that would work. We have no way to know what the actual numbers are because we have a sample size of one. The whole thing is just speculation until we have more actual data.
- MattPalmer1086 2y ago
  Well, the Fermi Paradox is misnamed because it isn't a paradox at all. It's just the observation that we don't see evidence of other life out there, and wondering why not - for which there are lots of possible explanations. As you say, we don't have enough data to know one way or another, but even when we do, there will still be no paradox.
  - layer8 2y ago
    The sheer number of stars in the galaxy and the absence of evidence of other life are in apparent contradiction — hence a paradox. A paradox doesn’t necessarily mean a hard logical contradiction.
    - mr_mitm 2y ago
      But this is not even a soft contradiction, or even an apparent contradiction. It's a problem with too many possible solutions so we don't know which one to pick. A paradox appears to have no solutions (until it's solved).
      - layer8 2y ago
        Given the number of stars, you would expect evidence of other life if life isn’t exceedingly rare. But we have no particular explanation why it would be exceedingly rare, and given the abundance of life on Earth one wouldn’t expect it. So the fact that we see no evidence runs against our expectations. Nonintuitive observations, where the observation doesn’t provide any explanation, already counts as a paradox.
        odyssey7 2y ago
        Well, it’s not a paradox if you assume you’re special. What else would you expect from the species that named itself “sapiens?”
    - api 2y ago
forgot-im-old 2y ago
It's popular to suggest we don't hear aliens because they all destroyed themselves. But a basic RF link budget calculation shows that even an Arecibo sized antenna pointed perfectly at another Arecibo telescope on an alien planet, and listening/transmitting at the exact right times, could only barely contact one or two of the nearest stars. This fact is buried in all the Fermi Paradox discussions because Fermi's point was the implications of his work on nuclear weapons when he brought up alien contact. It has since been used to make the case for Reagan's Strategic Defense Initiative. Which apparently Elon Musk is now continuing... https://ioc.exchange/@muskfiles https://ioc.exchange/@muskfiles
- throw9474 2y ago
  The most interesting discussion on Elon's nuclear weapons interception plans was xAI's, https://www.reddit.com/r/ChatGPT/comments/1dgyujd/comment/l8tgf79/ https://www.reddit.com/r/ChatGPT/comments/1dgyujd/comment/l8...
- nimish 2y ago
  I think people, for both good and bad faith reasons, vastly underestimate how unlikely it would be for any sort of artificial signal to reach us. It would need to be so powerful and so precisely aimed at us that firing randomly into the void would be pointless. We can barely detect the most energetic events in the universe like quasars and gamma ray bursts as it is. And that assumes we could even decode it -- advanced coding uses scrambling techniques that deliberately make the signal look like noise to the uninformed receiver...
  - exe34 2y ago
    presumably nowadays we would only aim at stars with a planet with an atmosphere we might at least suspect to be influenced by biology (i.e. contains some gas that couldn't be formed and maintained by known geological processes). so maybe aliens would see oxygen in our atmosphere and aim at us - but you'd still have to get the timing right: we might have been burning witches the last time one message came by and next time we might be in the midst of some other social disturbance.
- 2y ago
dmix 2y ago
Scalable interstellar space travel being infeasible for lifeforms and even robots in a way that could actually be useful (given distances, odds, 2 way communication, short time windows between extinctions etc) seems way more likely explanation than intelligent life being impossibly rare.
hansvm 2y ago
Are you using "the great filter" as a shorthand for any resolution to the Fermi paradox?
- MattPalmer1086 2y ago
  No, the argument here is specifically about the great filter. I know there are other possible resolutions to the Fermi paradox, although I haven't found most of them very convincing.
  - Enginerrrd 2y ago
    I mean the most obvious solution to the fermi paradox is just that aliens are hard to see. If we put an equivalent human civilization even on one of the explanets we've identified, we'd never know it. Our signals are simply too weak and disorganized, and the switch to digital has made them even harder to identify from the background. Planets are located right next to huge sources of radio noise: stars. Until we can reliably detect a species like ourselves on another planet, it seems very silly to assume they aren't there. The assumptions on detection all kind of assume that aliens that are much more advanced will have much more obvious signals of emery usage or other detectable signals, but I've never been convinced by these assumptions. Energy usage is likely a logistic curve rather than an ever expanding exponential. There so much room at the bottom for greater efficiency. It also seems quite sensible that a species either eventually copes with equilibrium or dies out due to issues with unchecked growth. There's SO MUCH energy available here on the earth that we could go for millenia of computational/energy growth while pursuing more efficient systems. The assumptions that lead to conclusions about megastructures are pretty dubious. I could go on at length about that, but I will just leave it at that.
    - marcosdumay 2y ago
      We can find life like our own hundreds of ligh-years away. And there are plenty of plans for improving this. Anyway, the Fermi paradox isn't about finding life on other planets.
    - 2y ago
Qem 2y ago
> If true, and complex life evolved more than once on the same planet, then it is much less likely as a strong candidate for the great filter [1]. The hard step was not complexification of life. It was long-term atmospheric oxygenation. It took two attempts, the first one short-lived, and between 3-4 billion years to finally succeed for good.
- marcosdumay 2y ago
  I vote on abiogenesis. But yeah, oxygenation is a good candidate. Anyway we don't have that much of certainty about how it happened exactly.
  - Qem 2y ago
    It's not necessary to assume a single hard step to explain the rarity of intelligent life. Considerations about the late appearance of a technological civilization on Earth point to between five and six hard steps from origin of life to us. Abiogenesis can account for one, oxygenation for another, and we still need to find another three or four more. See https://arxiv.org/pdf/0711.1985 https://arxiv.org/pdf/0711.1985
    - marcosdumay 2y ago
      That that paper is one (very good) explanation for the early and sudden appearance of life on Earth, despite it being presumed a rare phenomenon. But there are other possible explanations. About the Great Filter, in principle we can expect the probability of those things to vary by several orders of magnitude, so only one would qualify. All of them being equally unlikely is actually harder to explain than the alternative.
- com 2y ago
  It’s too early to say whether it is “for good”, unless you’re talking about atmospheric oxygenisation - that one almost certainly has an end date!
- MattPalmer1086 2y ago
njtransit 2y ago
Or the great filter is a misconception based on an extremely myopic view on the universe.
- exe34 2y ago
  possibly, but absence of evidence isn't evidence of presence.
- MattPalmer1086 2y ago
  Well true, the great filter may not be the entire explanation for the Fermi paradox. It seems uncontroversial though that the probability of each of the steps to get from lifeless to intelligent life will be a factor.
  - A_D_E_P_T 2y ago
    Possibly, but there's almost no way to meaningfully weigh any of the factors -- we still can't say to any degree of certainty whether the emergence of unicellular life in the cosmos is common or exceptionally rare -- so it's useless as a predictive tool, and highly constraining as a thought experiment.
    - MattPalmer1086 2y ago
      You say there's no way to weigh any of the factors, but the point of my original post was that the emergence of complex life more than once means that step is not as hard as it could have been. We also now know that the creation of organic molecules is commonplace in the cosmos. True, we don't get any predictive power from this. We're just exploring the space of possibilities, and there's still a lot of unknowns. I still see value in a thought framework like this to guide that exploration, but maybe there's a better approach?

bostonwalker 2y ago

The evolutionary transition from single-celled to multicellular life has actually been repeatedly accomplished in vitro [1]. So highly unlikely to be a Great Filter. [1] https://archive.ph/1yCVn https://archive.ph/1yCVn

sigmoid10 2y ago
The study in the article suggests that these early multicellular organisms failed to take hold. So there was probably something needed that was missing. And it still took billions of years for complex live to emerge, whereas single celled life appeared almost immediately once the earth cooled down enough to have liquid water. Whether it took two billion years or 3.5 doesn't matter so much when you think of it as a potential filter.

api 2y ago

There are so many more possibilities. The entire topic of the Fermi paradox is a massive tower of assumptions and hidden variables for which we have no information. We don’t even know the paradox is real since we haven’t explored our own solar system enough to rule out aliens or artifacts of their visits in our back yard, nor can we rule out advanced observers intentionally not revealing themselves for any number of rational reasons. There could be an abandoned underground alien base on the Moon and we’d have no clue. We have barely gone anywhere. If we hit, say, the level of development in The Expanse and still find nothing (no protomolecule haha) then maybe we can say there is definitely a paradox. There’s also the assumption that there is a single discrete big and dramatic great filter. That’s the Hollywood version. In reality there could just be a continuous probability of failure due to any number of events whether endogenous or external spread across billions of years that amounts to a great filter. The probability per day of “biosphere failure” or some other condition that dooms a potential spacefaring intelligence doesn’t need to be high to amount to a probability near 1.0 over geological time scales. Let’s say given we are sending our probes and capsules we are probably at least 50% of the way there. If the cumulative great filter were near 1.0 probability of failure this would imply a 50/50 probability of our success. Those are of course made up round numbers just to illustrate how that would work. We have no way to know what the actual numbers are because we have a sample size of one. The whole thing is just speculation until we have more actual data.

MattPalmer1086 2y ago
Well, the Fermi Paradox is misnamed because it isn't a paradox at all. It's just the observation that we don't see evidence of other life out there, and wondering why not - for which there are lots of possible explanations. As you say, we don't have enough data to know one way or another, but even when we do, there will still be no paradox.
- layer8 2y ago
  The sheer number of stars in the galaxy and the absence of evidence of other life are in apparent contradiction — hence a paradox. A paradox doesn’t necessarily mean a hard logical contradiction.
  - mr_mitm 2y ago
    But this is not even a soft contradiction, or even an apparent contradiction. It's a problem with too many possible solutions so we don't know which one to pick. A paradox appears to have no solutions (until it's solved).
    - layer8 2y ago
      Given the number of stars, you would expect evidence of other life if life isn’t exceedingly rare. But we have no particular explanation why it would be exceedingly rare, and given the abundance of life on Earth one wouldn’t expect it. So the fact that we see no evidence runs against our expectations. Nonintuitive observations, where the observation doesn’t provide any explanation, already counts as a paradox.
      - odyssey7 2y ago
        Well, it’s not a paradox if you assume you’re special. What else would you expect from the species that named itself “sapiens?”
  - api 2y ago

forgot-im-old 2y ago

It's popular to suggest we don't hear aliens because they all destroyed themselves. But a basic RF link budget calculation shows that even an Arecibo sized antenna pointed perfectly at another Arecibo telescope on an alien planet, and listening/transmitting at the exact right times, could only barely contact one or two of the nearest stars. This fact is buried in all the Fermi Paradox discussions because Fermi's point was the implications of his work on nuclear weapons when he brought up alien contact. It has since been used to make the case for Reagan's Strategic Defense Initiative. Which apparently Elon Musk is now continuing... https://ioc.exchange/@muskfiles https://ioc.exchange/@muskfiles

throw9474 2y ago
The most interesting discussion on Elon's nuclear weapons interception plans was xAI's, https://www.reddit.com/r/ChatGPT/comments/1dgyujd/comment/l8tgf79/ https://www.reddit.com/r/ChatGPT/comments/1dgyujd/comment/l8...
nimish 2y ago
I think people, for both good and bad faith reasons, vastly underestimate how unlikely it would be for any sort of artificial signal to reach us. It would need to be so powerful and so precisely aimed at us that firing randomly into the void would be pointless. We can barely detect the most energetic events in the universe like quasars and gamma ray bursts as it is. And that assumes we could even decode it -- advanced coding uses scrambling techniques that deliberately make the signal look like noise to the uninformed receiver...
- exe34 2y ago
  presumably nowadays we would only aim at stars with a planet with an atmosphere we might at least suspect to be influenced by biology (i.e. contains some gas that couldn't be formed and maintained by known geological processes). so maybe aliens would see oxygen in our atmosphere and aim at us - but you'd still have to get the timing right: we might have been burning witches the last time one message came by and next time we might be in the midst of some other social disturbance.
2y ago

dmix 2y ago

Scalable interstellar space travel being infeasible for lifeforms and even robots in a way that could actually be useful (given distances, odds, 2 way communication, short time windows between extinctions etc) seems way more likely explanation than intelligent life being impossibly rare.

hansvm 2y ago

Are you using "the great filter" as a shorthand for any resolution to the Fermi paradox?

MattPalmer1086 2y ago
No, the argument here is specifically about the great filter. I know there are other possible resolutions to the Fermi paradox, although I haven't found most of them very convincing.
- Enginerrrd 2y ago
  I mean the most obvious solution to the fermi paradox is just that aliens are hard to see. If we put an equivalent human civilization even on one of the explanets we've identified, we'd never know it. Our signals are simply too weak and disorganized, and the switch to digital has made them even harder to identify from the background. Planets are located right next to huge sources of radio noise: stars. Until we can reliably detect a species like ourselves on another planet, it seems very silly to assume they aren't there. The assumptions on detection all kind of assume that aliens that are much more advanced will have much more obvious signals of emery usage or other detectable signals, but I've never been convinced by these assumptions. Energy usage is likely a logistic curve rather than an ever expanding exponential. There so much room at the bottom for greater efficiency. It also seems quite sensible that a species either eventually copes with equilibrium or dies out due to issues with unchecked growth. There's SO MUCH energy available here on the earth that we could go for millenia of computational/energy growth while pursuing more efficient systems. The assumptions that lead to conclusions about megastructures are pretty dubious. I could go on at length about that, but I will just leave it at that.
  - marcosdumay 2y ago
    We can find life like our own hundreds of ligh-years away. And there are plenty of plans for improving this. Anyway, the Fermi paradox isn't about finding life on other planets.
  - 2y ago

Qem 2y ago

> If true, and complex life evolved more than once on the same planet, then it is much less likely as a strong candidate for the great filter [1]. The hard step was not complexification of life. It was long-term atmospheric oxygenation. It took two attempts, the first one short-lived, and between 3-4 billion years to finally succeed for good.

marcosdumay 2y ago
I vote on abiogenesis. But yeah, oxygenation is a good candidate. Anyway we don't have that much of certainty about how it happened exactly.
- Qem 2y ago
  It's not necessary to assume a single hard step to explain the rarity of intelligent life. Considerations about the late appearance of a technological civilization on Earth point to between five and six hard steps from origin of life to us. Abiogenesis can account for one, oxygenation for another, and we still need to find another three or four more. See https://arxiv.org/pdf/0711.1985 https://arxiv.org/pdf/0711.1985
  - marcosdumay 2y ago
    That that paper is one (very good) explanation for the early and sudden appearance of life on Earth, despite it being presumed a rare phenomenon. But there are other possible explanations. About the Great Filter, in principle we can expect the probability of those things to vary by several orders of magnitude, so only one would qualify. All of them being equally unlikely is actually harder to explain than the alternative.
com 2y ago
It’s too early to say whether it is “for good”, unless you’re talking about atmospheric oxygenisation - that one almost certainly has an end date!
MattPalmer1086 2y ago

njtransit 2y ago

Or the great filter is a misconception based on an extremely myopic view on the universe.

exe34 2y ago
possibly, but absence of evidence isn't evidence of presence.
MattPalmer1086 2y ago
Well true, the great filter may not be the entire explanation for the Fermi paradox. It seems uncontroversial though that the probability of each of the steps to get from lifeless to intelligent life will be a factor.
- A_D_E_P_T 2y ago
  Possibly, but there's almost no way to meaningfully weigh any of the factors -- we still can't say to any degree of certainty whether the emergence of unicellular life in the cosmos is common or exceptionally rare -- so it's useless as a predictive tool, and highly constraining as a thought experiment.
  - MattPalmer1086 2y ago
    You say there's no way to weigh any of the factors, but the point of my original post was that the emergence of complex life more than once means that step is not as hard as it could have been. We also now know that the creation of organic molecules is commonplace in the cosmos. True, we don't get any predictive power from this. We're just exploring the space of possibilities, and there's still a lot of unknowns. I still see value in a thought framework like this to guide that exploration, but maybe there's a better approach?