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Even if there are Earth like planets everywhere, we don’t know the probability that life appears spontaneously. Right? How does this change our outlook if one

Even if there are Earth like planets everywhere, we don’t know the probability that life appears spontaneously. Right? How does this change our outlook if one assumes The Great Filter hypothesis? Does this lower or increase that such a filter would be behind us or before us?

deleted 7y ago
[deleted]
rantwasp 7y ago
technically it's not spontaneous. There are some thoughts out there that organic compounds can emerge from non-organic ones and, given enough time, "life" will emerge. One of my favorite books on this is "Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves" by George Church. I have also seen arguments for this in "The Blind Watchmaker" by Dawkins that was published in 1986.
- sanxiyn 7y ago
  The Blind Watchmaker is mostly a book about evolution. Evolution does not explain origin of life, so it is not relevant here.
  - rantwasp 7y ago
    you are right that it’s mostly about evolution, but also touches on what may have given birth to life.
anon1m0us 7y ago
We do know the probability life appears is non-zero though, because it has happened. I don't know why all 9 steps to colonization can't be considered improbable, and therefore the filter be behind us and in front of us. We don't even know all the steps between "Step 8: Where we are" and "Step 9: Colonization." Maybe a moon is required for it. Maybe materials not found on this earth are required for it. I think we as a species have decided that colonizing Mars is possible. It might not be probable, but we can do it. We know how, we just haven't yet. Humans just might be the first intelligent life. If the Milky Way was already colonized, some civilization made the first leap to another planet. It's manifest destiny. We have to colonize the universe. It's our moral duty as an intelligent species to maintain awareness of the universe.
- PeterisP 7y ago
  "Humans just might be the first intelligent life." is incompatible with the notion that life is common (which may or may not be true) - our planet is a bit older than the average (e.g. the examples in the article are suns/planets which have already gone through all the lifecycle that Earth will have eventually), so it's probable that we're the first intelligent life in the galaxy if and only if it's likely that we're the only intelligent life that the galaxy will ever spawn. If there's no great filter before our current stage, then it's extremely unlikely that we're the first intelligent life in galaxy, and either there's a great filter after that or many civilizations have risen already (and have had more than enough time to colonize the whole galaxy a thousand times over at a relaxed, leisurely slow pace, if any of these civilizations wanted to) but we just don't see them for some reason.
  - blackflame 7y ago
    Just because something is unlikely doesn't mean it can't happen. Furthermore, there could be something very special about Earth's position that makes it far more likely than we initially calculate. It doesn't make sense to dismiss theories as 'unlikely' when our degree of understanding of that probability is absurdly primitive.
    - PeterisP 7y ago
      "something very special about Earth's position that makes it far more likely than we initially calculate" - makes what far more likely ? Spawning life? If so, then that special factor, whatever it is, would simply be an example of a great filter behind us. I'm not saying that we can't be the first ones, I'm just noting that us being the first implies that we're alone in the galaxy. To make that point perhaps more clearly, let's say that before and including us, our galaxy has had X planets like Earth. Whatever that X is (1 or 1000 or billions), the total number of such planets that our galaxy will ever have is less than 2X. That doesn't rely on any poorly understood theories, that doesn't rely on any aspects of how life or intelligence might form - the lifecycle of stars is well understood, the age of universe is well understood, and the future has less new stars and planets than the past; we're currently past the midpoint of star/planet forming and that's that, most of the planets that will ever exist in our galaxy either exist right now (most of them for longer than Earth) or are gone already. So whatever the "dice" of a suitable planet existing and creating intelligent life are - if we're the first ones (and I'm not making a point whether we are or aren't, whether that's likely or not, that "if" is an assumption), if X rolls of dice resulted in just a single success - then the remaining less than X rolls simply won't suddenly roll a hundred more successes; if the total number of spawned civilizations until us is 1, then that means that the total number of spawned civilizations until end of the universe would be 1 or 2 - and if it's 2, then it would be a hit-by-a-lightning-while-typing-this level of coincidence is that second one happened to arise at the same insignificantly tiny moment in time that constitutes the existence of homo sapiens until now, just some tiny 100 000 years after us instead of some 10 000 000 or much more years after us. OR, possibly, there are and will be much more civilizations than that - but then some of them have been long before us.
the8472 7y ago
We don't know. The confidence intervals on individual probability distributions are already wide and long-tailed but convolving them only makes the problem worse. https://arxiv.org/pdf/1806.02404.pdf https://arxiv.org/pdf/1806.02404.pdf
Iv 7y ago
The last years have given us two estimates of previously unknown factors in the Drake equation, that's why everybody is excited. Yes, life could be very improbable to appear, but there is a counterargument to this hypothesis: on our planet, life appeared almost immediately once the crust solidified and oceans appeared. If there had been a 3 billion years period, there may have been an argument that maybe we got very lucky it appeared at all, but we have fossils that are just 100 mil years younger than the apparition of oceans. And we keep finding older ones. If life was a really rare occurrence that would mean we would have been lucky twice: that it appeared at all and that it appeared that early. > Does this lower or increase that such a filter would be behind us or before us? When so many things are unknown, it makes little sense to talk about probabilities. It removes a possibility for a filter behind us. I still have doubts that evolution necessary leads to intelligent life. When I started getting interested into evolution, my main surprise was that there is no "optimal" unicellular life-form. Why isn't the earth covered by a green pellicule of photosynthesis-able cells that would be a Kardashev I organism without ever reaching intelligence? I still don't understand why it did not happen. Evolution favored competition to optimality and the reasons are unclear. I would not be surprised that evolution in other ecosystems would result in one organism "winning" over all the others. My personal opinion is that we will find a lot of life on other planets, but many will be unicellular and many will show an evolutionary process that is stuck in a dead-end. I expect intelligent life to be rare, and that the "great filter" is that we will find things much more worthy of our time and energy than colonizing the universe or doing mega-engineering projects. Maybe we'll colonize a few star, build a Dyson star or two, but then we will discover that everyone prefers to spend time in another dimension, or in infinite pocket-universes. Maybe the real party is inside the black holes or the neutron stars and all the advanced civilizations are waiting for us to figure it out. The idea that an intelligent species would colonize the universe assumes that it does not manage to handle its demography or views its growth as a good thing. I doubt that this is a rational conclusion once you reached the state of full automation.
- xornox 7y ago
  Green unicellular life-form is perfect food and energy source same way as energy of sun is. Evolution does not stop if there are easy energy sources available everywhere. Nature does not care if energy of sun is used optimally or not. It just cares if offsprings live or not.
lend000 7y ago
The Great Filter hypothesis assumes that a society that has the capability to expand and colonize would do so without exception and make its presence known to more primitive civilizations. That's a pretty big assumption. Just look at how ridiculous most futurism of the early 20th century already seems (both culturally and technologically), and then consider trying to relate to the continuation of human civilization after ten million years. When we try to envision the future, it is still rooted in the familiar. I suspect ten million years from now (if our society continues on that long in some capacity), just about everything will be so fundamentally unrecognizable (including the continuation of humans, if there is still a biological form at all) as to make relating to their intentions or even trying to identify whether they exist from afar with primitive technology futile. There's more hard evidence of "pseudo-magical objects that don't seem to wish to be seen up close" here on our Earthly radar systems than there is of the actual conditions on planets in neighboring habitable zones to confirm or deny life and start establishing probabilities.
- PhasmaFelis 7y ago
  > The Great Filter hypothesis assumes that a society that has the capability to expand and colonize would do so without exception It doesn't assume that. (Explicitly doesn't; that's step 9 of 9, with modern humanity at step 8.) It just observes that we have no evidence of extraterrestrial life spreading out from their home system and colonizing the universe, and discusses some possible reasons for that.

deleted 7y ago

[deleted]

rantwasp 7y ago

technically it's not spontaneous. There are some thoughts out there that organic compounds can emerge from non-organic ones and, given enough time, "life" will emerge. One of my favorite books on this is "Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves" by George Church. I have also seen arguments for this in "The Blind Watchmaker" by Dawkins that was published in 1986.

sanxiyn 7y ago
The Blind Watchmaker is mostly a book about evolution. Evolution does not explain origin of life, so it is not relevant here.
- rantwasp 7y ago
  you are right that it’s mostly about evolution, but also touches on what may have given birth to life.

anon1m0us 7y ago

We do know the probability life appears is non-zero though, because it has happened. I don't know why all 9 steps to colonization can't be considered improbable, and therefore the filter be behind us and in front of us. We don't even know all the steps between "Step 8: Where we are" and "Step 9: Colonization." Maybe a moon is required for it. Maybe materials not found on this earth are required for it. I think we as a species have decided that colonizing Mars is possible. It might not be probable, but we can do it. We know how, we just haven't yet. Humans just might be the first intelligent life. If the Milky Way was already colonized, some civilization made the first leap to another planet. It's manifest destiny. We have to colonize the universe. It's our moral duty as an intelligent species to maintain awareness of the universe.

PeterisP 7y ago
"Humans just might be the first intelligent life." is incompatible with the notion that life is common (which may or may not be true) - our planet is a bit older than the average (e.g. the examples in the article are suns/planets which have already gone through all the lifecycle that Earth will have eventually), so it's probable that we're the first intelligent life in the galaxy if and only if it's likely that we're the only intelligent life that the galaxy will ever spawn. If there's no great filter before our current stage, then it's extremely unlikely that we're the first intelligent life in galaxy, and either there's a great filter after that or many civilizations have risen already (and have had more than enough time to colonize the whole galaxy a thousand times over at a relaxed, leisurely slow pace, if any of these civilizations wanted to) but we just don't see them for some reason.
- blackflame 7y ago
  Just because something is unlikely doesn't mean it can't happen. Furthermore, there could be something very special about Earth's position that makes it far more likely than we initially calculate. It doesn't make sense to dismiss theories as 'unlikely' when our degree of understanding of that probability is absurdly primitive.
  - PeterisP 7y ago
    "something very special about Earth's position that makes it far more likely than we initially calculate" - makes what far more likely ? Spawning life? If so, then that special factor, whatever it is, would simply be an example of a great filter behind us. I'm not saying that we can't be the first ones, I'm just noting that us being the first implies that we're alone in the galaxy. To make that point perhaps more clearly, let's say that before and including us, our galaxy has had X planets like Earth. Whatever that X is (1 or 1000 or billions), the total number of such planets that our galaxy will ever have is less than 2X. That doesn't rely on any poorly understood theories, that doesn't rely on any aspects of how life or intelligence might form - the lifecycle of stars is well understood, the age of universe is well understood, and the future has less new stars and planets than the past; we're currently past the midpoint of star/planet forming and that's that, most of the planets that will ever exist in our galaxy either exist right now (most of them for longer than Earth) or are gone already. So whatever the "dice" of a suitable planet existing and creating intelligent life are - if we're the first ones (and I'm not making a point whether we are or aren't, whether that's likely or not, that "if" is an assumption), if X rolls of dice resulted in just a single success - then the remaining less than X rolls simply won't suddenly roll a hundred more successes; if the total number of spawned civilizations until us is 1, then that means that the total number of spawned civilizations until end of the universe would be 1 or 2 - and if it's 2, then it would be a hit-by-a-lightning-while-typing-this level of coincidence is that second one happened to arise at the same insignificantly tiny moment in time that constitutes the existence of homo sapiens until now, just some tiny 100 000 years after us instead of some 10 000 000 or much more years after us. OR, possibly, there are and will be much more civilizations than that - but then some of them have been long before us.

the8472 7y ago

We don't know. The confidence intervals on individual probability distributions are already wide and long-tailed but convolving them only makes the problem worse. https://arxiv.org/pdf/1806.02404.pdf https://arxiv.org/pdf/1806.02404.pdf

Iv 7y ago

The last years have given us two estimates of previously unknown factors in the Drake equation, that's why everybody is excited. Yes, life could be very improbable to appear, but there is a counterargument to this hypothesis: on our planet, life appeared almost immediately once the crust solidified and oceans appeared. If there had been a 3 billion years period, there may have been an argument that maybe we got very lucky it appeared at all, but we have fossils that are just 100 mil years younger than the apparition of oceans. And we keep finding older ones. If life was a really rare occurrence that would mean we would have been lucky twice: that it appeared at all and that it appeared that early. > Does this lower or increase that such a filter would be behind us or before us? When so many things are unknown, it makes little sense to talk about probabilities. It removes a possibility for a filter behind us. I still have doubts that evolution necessary leads to intelligent life. When I started getting interested into evolution, my main surprise was that there is no "optimal" unicellular life-form. Why isn't the earth covered by a green pellicule of photosynthesis-able cells that would be a Kardashev I organism without ever reaching intelligence? I still don't understand why it did not happen. Evolution favored competition to optimality and the reasons are unclear. I would not be surprised that evolution in other ecosystems would result in one organism "winning" over all the others. My personal opinion is that we will find a lot of life on other planets, but many will be unicellular and many will show an evolutionary process that is stuck in a dead-end. I expect intelligent life to be rare, and that the "great filter" is that we will find things much more worthy of our time and energy than colonizing the universe or doing mega-engineering projects. Maybe we'll colonize a few star, build a Dyson star or two, but then we will discover that everyone prefers to spend time in another dimension, or in infinite pocket-universes. Maybe the real party is inside the black holes or the neutron stars and all the advanced civilizations are waiting for us to figure it out. The idea that an intelligent species would colonize the universe assumes that it does not manage to handle its demography or views its growth as a good thing. I doubt that this is a rational conclusion once you reached the state of full automation.

xornox 7y ago
Green unicellular life-form is perfect food and energy source same way as energy of sun is. Evolution does not stop if there are easy energy sources available everywhere. Nature does not care if energy of sun is used optimally or not. It just cares if offsprings live or not.

lend000 7y ago

The Great Filter hypothesis assumes that a society that has the capability to expand and colonize would do so without exception and make its presence known to more primitive civilizations. That's a pretty big assumption. Just look at how ridiculous most futurism of the early 20th century already seems (both culturally and technologically), and then consider trying to relate to the continuation of human civilization after ten million years. When we try to envision the future, it is still rooted in the familiar. I suspect ten million years from now (if our society continues on that long in some capacity), just about everything will be so fundamentally unrecognizable (including the continuation of humans, if there is still a biological form at all) as to make relating to their intentions or even trying to identify whether they exist from afar with primitive technology futile. There's more hard evidence of "pseudo-magical objects that don't seem to wish to be seen up close" here on our Earthly radar systems than there is of the actual conditions on planets in neighboring habitable zones to confirm or deny life and start establishing probabilities.

PhasmaFelis 7y ago
> The Great Filter hypothesis assumes that a society that has the capability to expand and colonize would do so without exception It doesn't assume that. (Explicitly doesn't; that's step 9 of 9, with modern humanity at step 8.) It just observes that we have no evidence of extraterrestrial life spreading out from their home system and colonizing the universe, and discusses some possible reasons for that.