5 ms·

I hope they don't. It would be a very bad indicator for our future in the cosmos, making it far more likely that whatever great filter is out there, is in fron

I hope they don't. It would be a very bad indicator for our future in the cosmos, making it far more likely that whatever great filter is out there, is in front of us still.

sudofail 5y ago
Not necessarily. Before the great filter, there's the jump to multi-cellular life. As far as we know, the symbioses with mitochondria bacteria only happened once, and is the progenesis of all multi-cellular life on earth. So single-celled life may not be terribly uncommon throughout the cosmos.
- csee 5y ago
  > Before the great filter, there's the jump to multi-cellular life. Well, the filter may exist prior to the jump to multi-cellular life. Finding early life on Mars would necessarily be bad because we would now be able to mostly eliminate that possibility, which means that the probability that the filter is ahead of us increases.
  - s1artibartfast 5y ago
    I disagree. While finding dead life on other planets decreases the probability of some filters, it also increases the probability of other filters. For example, if we go to every planet in the solar system and see evidence of extinct multi-cellular life, but no sapient life, this would suggest that the filter is indeed behind us, and not in front of us.
    - bpodgursky 5y ago
      I don't think this is right. It moves the filter forward from "no life" to "no intelligent life" (If we have a TON of examples – remember, we are also a data point. so even if we find 200 planets with dead multicellular life, we still have 1/200 making it to spacefaring — that's a huge % when extrapolated out to a galactic scale! It's a large enough % that I don't even find this to be a meaningful prior adjustment). It also adds no information as to which, if any, filters are in front of us. How would "lot of dead fish" help us understand "do civilizations destroy themselves with nuclear weapons"?
      - s1artibartfast 5y ago
        I agree with the first part, but not the second. Agreed it would rule out some early filters. But for the second part, the ratio doesn't go to 1 in 200. That's not how the anthropic principle works. You're already assuming that the Earth is extraordinary oh, so you can't just put it in the data set. Instead you would look at 199 out of 199 planets where sapient life capable of making an observation failed to develop. Agreed that it provides no data on future filters ahead of us
        csee 5y ago
        > Agreed that it provides no data on future filters ahead of us This was my instinct, too, after reading both of your posts, but on reflection I think that it's unlikely to be no information. If we instead found 199 examples of extinct complex life (say, fossilized rodent-like creatures), instead of extinct simple life, we all probably agree that this would increase the odds of the filter being in front of us. Now, imagine gradually changing the example from extinct complex life (rodent-type creatures) and going down to extinct simple life. At what point in this thought experiment does it become "no data"?
        s1artibartfast 5y ago
        I guess I agree that discovering extinct life is information about probabilistic filters in earths future. I But, it does have to be weighed against the newly observed data supporting filters humans have already past. To take your example, as we keep finding rodent fossils, we become more confident that a filter exists between rat and rocket-men. As we go from 0 planets with rodent fossils to 1 trillion planets, the probability that this is the filter keeps going up. That is to say, we are not only decreasing the chance of pre-rat filters, but simultaneously increasing the chance that the filter is in the rat stage.
shawnz 5y ago
Isn't that backwards? The great filter is meant to explain why we don't see extraterrestrial life, so finding it would be counterevidence for a great filter
- deleted 5y ago
  [deleted]
- csee 5y ago
  It's correct. There is still a filter somewhere that explains the Fermi Paradox. So finding evidence of primordial life on Mars would just mean that the filter exists somewhere between that primordial life and somewhere ahead of us. That is bad, because it increases the probability that the filter is ahead of us by eliminating the possibility that the filter was behind that primordial life.
  - shawnz 5y ago
    If we assume that the great filter is ahead of us, then we were already a better lower bound. If it's behind us, then who cares?
    - csee 5y ago
      If it's at all possible that it's behind us (which I believe it is), then this finding would be bad, because it necessarily shifts probability density into our future. Probability density must sum to 1. So eliminating one large chunk of possibility will necessarily increase the odds that the filter is in our future.
      - bpodgursky 5y ago
        Yes, thank you for fleshing out what I meant.
      - ALittleLight 5y ago
        Unless, for example, we were to find Mars had and has single cellular life. That might increase the likelihood that the filter is at the single to multicellular phase by enough to offset the bad news that the filter is not the abiogenesis step.
fnord77 5y ago
I don't think there's just one great filter. I imagine there are various filters depending on the particular environment and circumstances. Several are behind us already. Several are ahead.
- cout 5y ago
  The filter might also not be one in which a civilization goes extinct but one in which the civilization goes dark to any outside observers. What if the ultimate fate of any sufficiently sophisticated species is to harness their sun's energy to create and enter a pocket universe where the stars are still close enough together to travel between them at light speed?
booleandilemma 5y ago
This isn’t an original opinion, it’s taken from this paper: https://www.nickbostrom.com/extraterrestrial.pdf https://www.nickbostrom.com/extraterrestrial.pdf
- bpodgursky 5y ago
  I hadn't seen this post, but I'm glad he agrees. It's not a hard opinion to reach independently when you work through the math.
- exdsq 5y ago
  And I believe Bostrom was just summarizing the Fermi Paradox https://en.m.wikipedia.org/wiki/Fermi_paradox https://en.m.wikipedia.org/wiki/Fermi_paradox

I hope they don't. It would be a very bad indicator for our future in the cosmos, making it far more likely that whatever great filter is out there, is in front of us still.

sudofail 5y ago

Not necessarily. Before the great filter, there's the jump to multi-cellular life. As far as we know, the symbioses with mitochondria bacteria only happened once, and is the progenesis of all multi-cellular life on earth. So single-celled life may not be terribly uncommon throughout the cosmos.

csee 5y ago
> Before the great filter, there's the jump to multi-cellular life. Well, the filter may exist prior to the jump to multi-cellular life. Finding early life on Mars would necessarily be bad because we would now be able to mostly eliminate that possibility, which means that the probability that the filter is ahead of us increases.
- s1artibartfast 5y ago
  I disagree. While finding dead life on other planets decreases the probability of some filters, it also increases the probability of other filters. For example, if we go to every planet in the solar system and see evidence of extinct multi-cellular life, but no sapient life, this would suggest that the filter is indeed behind us, and not in front of us.
  - bpodgursky 5y ago
    I don't think this is right. It moves the filter forward from "no life" to "no intelligent life" (If we have a TON of examples – remember, we are also a data point. so even if we find 200 planets with dead multicellular life, we still have 1/200 making it to spacefaring — that's a huge % when extrapolated out to a galactic scale! It's a large enough % that I don't even find this to be a meaningful prior adjustment). It also adds no information as to which, if any, filters are in front of us. How would "lot of dead fish" help us understand "do civilizations destroy themselves with nuclear weapons"?
    - s1artibartfast 5y ago
      I agree with the first part, but not the second. Agreed it would rule out some early filters. But for the second part, the ratio doesn't go to 1 in 200. That's not how the anthropic principle works. You're already assuming that the Earth is extraordinary oh, so you can't just put it in the data set. Instead you would look at 199 out of 199 planets where sapient life capable of making an observation failed to develop. Agreed that it provides no data on future filters ahead of us
      - csee 5y ago
        > Agreed that it provides no data on future filters ahead of us This was my instinct, too, after reading both of your posts, but on reflection I think that it's unlikely to be no information. If we instead found 199 examples of extinct complex life (say, fossilized rodent-like creatures), instead of extinct simple life, we all probably agree that this would increase the odds of the filter being in front of us. Now, imagine gradually changing the example from extinct complex life (rodent-type creatures) and going down to extinct simple life. At what point in this thought experiment does it become "no data"?
        s1artibartfast 5y ago
        I guess I agree that discovering extinct life is information about probabilistic filters in earths future. I But, it does have to be weighed against the newly observed data supporting filters humans have already past. To take your example, as we keep finding rodent fossils, we become more confident that a filter exists between rat and rocket-men. As we go from 0 planets with rodent fossils to 1 trillion planets, the probability that this is the filter keeps going up. That is to say, we are not only decreasing the chance of pre-rat filters, but simultaneously increasing the chance that the filter is in the rat stage.

shawnz 5y ago

Isn't that backwards? The great filter is meant to explain why we don't see extraterrestrial life, so finding it would be counterevidence for a great filter

deleted 5y ago
[deleted]
csee 5y ago
It's correct. There is still a filter somewhere that explains the Fermi Paradox. So finding evidence of primordial life on Mars would just mean that the filter exists somewhere between that primordial life and somewhere ahead of us. That is bad, because it increases the probability that the filter is ahead of us by eliminating the possibility that the filter was behind that primordial life.
- shawnz 5y ago
  If we assume that the great filter is ahead of us, then we were already a better lower bound. If it's behind us, then who cares?
  - csee 5y ago
    If it's at all possible that it's behind us (which I believe it is), then this finding would be bad, because it necessarily shifts probability density into our future. Probability density must sum to 1. So eliminating one large chunk of possibility will necessarily increase the odds that the filter is in our future.
    - bpodgursky 5y ago
      Yes, thank you for fleshing out what I meant.
    - ALittleLight 5y ago
      Unless, for example, we were to find Mars had and has single cellular life. That might increase the likelihood that the filter is at the single to multicellular phase by enough to offset the bad news that the filter is not the abiogenesis step.

fnord77 5y ago

I don't think there's just one great filter. I imagine there are various filters depending on the particular environment and circumstances. Several are behind us already. Several are ahead.

cout 5y ago
The filter might also not be one in which a civilization goes extinct but one in which the civilization goes dark to any outside observers. What if the ultimate fate of any sufficiently sophisticated species is to harness their sun's energy to create and enter a pocket universe where the stars are still close enough together to travel between them at light speed?

booleandilemma 5y ago

This isn’t an original opinion, it’s taken from this paper: https://www.nickbostrom.com/extraterrestrial.pdf https://www.nickbostrom.com/extraterrestrial.pdf

bpodgursky 5y ago
I hadn't seen this post, but I'm glad he agrees. It's not a hard opinion to reach independently when you work through the math.
exdsq 5y ago
And I believe Bostrom was just summarizing the Fermi Paradox https://en.m.wikipedia.org/wiki/Fermi_paradox https://en.m.wikipedia.org/wiki/Fermi_paradox