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The universe we find ourselves in isn't very compatible with a species like our surviving for an extended period. If humans exist for millions of years we're go

The universe we find ourselves in isn't very compatible with a species like our surviving for an extended period. If humans exist for millions of years we're going to either spread out to fill the galaxy or our machines will. The fact earth was free to develop us means that no other species like us existed long enough to beat us to it. We ought to hope that's because species find some other priority besides expansion and power, because otherwise the reason we're free to exist is because species like us always wipe themselves out before they spread.

marcosdumay 4y ago
> because otherwise the reason we're free to exist is because species like us always wipe themselves out before they spread That's a complete non-sequitur. There can be plenty of reasons for a species like us never appearing on the first place, and they are way more reasonable than postulating that life like us always destroy itself.
- cortic 4y ago
  We are actually running out of places in our history to fit a great filter. Most of the events in our evolution seem probable, even inevitable. In fact the only place IMO that's really left is the emergence of the first self replicating RNA molecule. But even that seems too probable to be a great filter. And if its not behind us, it has to be in-front of us or we are under a great misapprehension about the nature of the universe.
  - kiba 4y ago
    Probably, inevitable based on what sample size?
    - bena 4y ago
      Techno-optimism. We didn't have planes, now we have planes. We rode horses and now we go to the moon. Therefore, anything you can possibly imagine is inevitable because "technology". We will circumvent every possible logistical and physical barrier because of nebulous reasons. It's a lot like that scene in Silicon Valley when Big Head is pitching a neuralink-esque device for a phone to the CEO and the CEO asks how long it will take and Big Head says "Soon, we just got to figure out how". Like, no shit, the "how" isn't just the important part, it's the only part.
  - btilly 4y ago
    BS. Filter 1. If we had no large moon, roughly every 30 million years or so our axial tilt would become too extreme for life. We do not have another example of a planet with a moon to rival ours in relative size. Filter 2. Without Jupiter acting as a cosmic vacuum cleaner, we'd predictably be hit by enough asteroids and comets that we'd never have evolved. In thousands of solar systems that we've found, we've found lots with rocky planets, and lots with gas giants. Ours is the only system with BOTH rocky planets AND gas giants. Filter 3. Supernovas are dangerous. For example we are currently in the Local Bubble. Which is the result of a supernova about 4 million years ago which would have wiped us out if we were this close when it happened. Luckily for us we have a weird orbit where we only pass through the galactic plane every 30 million years or so, and spend most of our time well away from potential supernovas. Filter 4. Planets need to be in the habitable zone, around a star where that zone remains habitable for a very long period. Most solar systems have no suitable planet. Putting these together on a back of the envelope, it is likely that we're the only solar system in our galaxy which is likely to remain habitable and stable for long enough that complex intelligent life could evolve.
    - JumpCrisscross 4y ago
      My big one is multicellular life. Mitochondria are sooo weird.
      - btilly 4y ago
        Multicellular happened over and over again. Mitochondria are weird, but we don't know that such organelles are necessary for life to become intelligent. And we don't know how weird that capture was. It is easy to make an argument for improbability. And it is easy to make it too extreme, like the absurd arguments that Creationists use against evolution.
    - worldsayshi 4y ago
      Mentioned elsewhere in the thread: Filter N: Even if life is complex it might not be likely to become intelligent enough to send signals and venture into space. It took quite a long time before we showed up.
  - antonvs 4y ago
    > We are actually running out of places in our history to fit a great filter. Other than the obvious, which is the utter physical, technological, economic, political, biological, and statistical impracticality of interstellar colonization.
- Izkata 4y ago
  > There can be plenty of reasons for a species like us never appearing on the first place We already have an example of it, too: Look how long the dinosaurs were around compared to humans.
  - worldsayshi 4y ago
    Yes I wonder if there was some particular condition that prevented higher intelligence to occur before recently. Or if it's just sort of "pure chance".
    - marcosdumay 4y ago
      Abiogenesis seems so absurdly unlikely that it's enough to explain the Fermi paradox a couple of times and still get some extra margin all by itself.
AlanSE 4y ago
That argument seems to violate the basic rules of exponentials. If an advanced species did settle on an stasis, then that will only last until some subset of the population decides to go beyond the stasis. Particularly for a space-faring civilization, the time scales and resources are so fast, that any multiplication factor beyond unity will eventually go bananas. Any individuals with the prerogative to multiply will swamp those who lack it, same with Earth evolution. The selfish gene will prevail unless there is centralized control. I don't have any problem with this reading - advanced space-fairing beings have never existed in our light cone. SETI won't find anything because there's nothing there. We have a good chance of making it ourselves, but it's 50/50 because we have no priors, our decisions actually matter.
- AnimalMuppet 4y ago
  But in real life, it never actually is an exponential. There always is some limiting resource or saturation point or something, that turns it from an exponential into an S curve. An argument based on "the basic rules of exponentials" typically ignores second-order effects (there seem to always be some, even if we may not be able to see them in advance). > that will only last until some subset of the population decides to go beyond the stasis. You are assuming that they can go beyond the stasis. I'm not sure that's a valid assumption.
  - Nevermark 4y ago
    Well yes, after the distance to the our solar system’s other resources, the next pauses in exponential expansion would be crossing to the next star system, then the spaces to other galaxies, and then to other galaxy clusters. There are not a lot of opportunities to saturate & stall once we sustainably develop resources beyond Earth And stalls or extinctions due to conflict become very unlikely after we colonize a few systems
  - btilly 4y ago
    It never is truly an exponential in the limit, but exponential growth for surprisingly long times is very common.
- 4y ago
Scarblac 4y ago
I am not convinced that self replicating machines spreading out between stars is possible. There's rather a lot that the machine has to be able to do on a destination planet to set up mines and factories etc before the first extra machine can be made,and it has to survive landing.

marcosdumay 4y ago

> because otherwise the reason we're free to exist is because species like us always wipe themselves out before they spread That's a complete non-sequitur. There can be plenty of reasons for a species like us never appearing on the first place, and they are way more reasonable than postulating that life like us always destroy itself.

cortic 4y ago
We are actually running out of places in our history to fit a great filter. Most of the events in our evolution seem probable, even inevitable. In fact the only place IMO that's really left is the emergence of the first self replicating RNA molecule. But even that seems too probable to be a great filter. And if its not behind us, it has to be in-front of us or we are under a great misapprehension about the nature of the universe.
- kiba 4y ago
  Probably, inevitable based on what sample size?
  - bena 4y ago
    Techno-optimism. We didn't have planes, now we have planes. We rode horses and now we go to the moon. Therefore, anything you can possibly imagine is inevitable because "technology". We will circumvent every possible logistical and physical barrier because of nebulous reasons. It's a lot like that scene in Silicon Valley when Big Head is pitching a neuralink-esque device for a phone to the CEO and the CEO asks how long it will take and Big Head says "Soon, we just got to figure out how". Like, no shit, the "how" isn't just the important part, it's the only part.
- btilly 4y ago
  BS. Filter 1. If we had no large moon, roughly every 30 million years or so our axial tilt would become too extreme for life. We do not have another example of a planet with a moon to rival ours in relative size. Filter 2. Without Jupiter acting as a cosmic vacuum cleaner, we'd predictably be hit by enough asteroids and comets that we'd never have evolved. In thousands of solar systems that we've found, we've found lots with rocky planets, and lots with gas giants. Ours is the only system with BOTH rocky planets AND gas giants. Filter 3. Supernovas are dangerous. For example we are currently in the Local Bubble. Which is the result of a supernova about 4 million years ago which would have wiped us out if we were this close when it happened. Luckily for us we have a weird orbit where we only pass through the galactic plane every 30 million years or so, and spend most of our time well away from potential supernovas. Filter 4. Planets need to be in the habitable zone, around a star where that zone remains habitable for a very long period. Most solar systems have no suitable planet. Putting these together on a back of the envelope, it is likely that we're the only solar system in our galaxy which is likely to remain habitable and stable for long enough that complex intelligent life could evolve.
  - JumpCrisscross 4y ago
    My big one is multicellular life. Mitochondria are sooo weird.
    - btilly 4y ago
      Multicellular happened over and over again. Mitochondria are weird, but we don't know that such organelles are necessary for life to become intelligent. And we don't know how weird that capture was. It is easy to make an argument for improbability. And it is easy to make it too extreme, like the absurd arguments that Creationists use against evolution.
  - worldsayshi 4y ago
    Mentioned elsewhere in the thread: Filter N: Even if life is complex it might not be likely to become intelligent enough to send signals and venture into space. It took quite a long time before we showed up.
- antonvs 4y ago
  > We are actually running out of places in our history to fit a great filter. Other than the obvious, which is the utter physical, technological, economic, political, biological, and statistical impracticality of interstellar colonization.
Izkata 4y ago
> There can be plenty of reasons for a species like us never appearing on the first place We already have an example of it, too: Look how long the dinosaurs were around compared to humans.
- worldsayshi 4y ago
  Yes I wonder if there was some particular condition that prevented higher intelligence to occur before recently. Or if it's just sort of "pure chance".
  - marcosdumay 4y ago
    Abiogenesis seems so absurdly unlikely that it's enough to explain the Fermi paradox a couple of times and still get some extra margin all by itself.

AlanSE 4y ago

That argument seems to violate the basic rules of exponentials. If an advanced species did settle on an stasis, then that will only last until some subset of the population decides to go beyond the stasis. Particularly for a space-faring civilization, the time scales and resources are so fast, that any multiplication factor beyond unity will eventually go bananas. Any individuals with the prerogative to multiply will swamp those who lack it, same with Earth evolution. The selfish gene will prevail unless there is centralized control. I don't have any problem with this reading - advanced space-fairing beings have never existed in our light cone. SETI won't find anything because there's nothing there. We have a good chance of making it ourselves, but it's 50/50 because we have no priors, our decisions actually matter.

AnimalMuppet 4y ago
But in real life, it never actually is an exponential. There always is some limiting resource or saturation point or something, that turns it from an exponential into an S curve. An argument based on "the basic rules of exponentials" typically ignores second-order effects (there seem to always be some, even if we may not be able to see them in advance). > that will only last until some subset of the population decides to go beyond the stasis. You are assuming that they can go beyond the stasis. I'm not sure that's a valid assumption.
- Nevermark 4y ago
  Well yes, after the distance to the our solar system’s other resources, the next pauses in exponential expansion would be crossing to the next star system, then the spaces to other galaxies, and then to other galaxy clusters. There are not a lot of opportunities to saturate & stall once we sustainably develop resources beyond Earth And stalls or extinctions due to conflict become very unlikely after we colonize a few systems
- btilly 4y ago
  It never is truly an exponential in the limit, but exponential growth for surprisingly long times is very common.
4y ago

Scarblac 4y ago

I am not convinced that self replicating machines spreading out between stars is possible. There's rather a lot that the machine has to be able to do on a destination planet to set up mines and factories etc before the first extra machine can be made,and it has to survive landing.