4 ms·

At the numbers we’re looking at, even if only 1% of civilizations (maybe even 1 in 1000) would be exponentially expansionary, they would still make themselves f

At the numbers we’re looking at, even if only 1% of civilizations (maybe even 1 in 1000) would be exponentially expansionary, they would still make themselves fairly obvious and outcompete all the others. The Fermi paradox doesn’t assume that all extraterrestrial intelligence behaves this way, but this rebuttal has to assume that no ETI would behave this way. And that seems improbable, if only because aggressive, exponential expansion is a fairly valid Darwinian strategy.

acqq 6y ago
> aggressive, exponential expansion is a fairly valid Darwinian strategy. Earth exists for around 4.5 billion years, life on Earth for 3.5 billion years, the whole known Universe just less than 14 billion years (and we can send some small probes to the limits of our own Solar system only during the last decades). So the Universe is not "old" and the distances between the areas suitable for the life to "expand" are immense and real barriers. Knowing the distances involved, I believe that had we discovered that we are in much later age of the Universe, not seeing "others" would mean more than it means now. For now, knowing the distances, whatever could be somewhere far could simply be too far from us, nothing more. Edit: Re: "The galaxy is only 100,000 light years across" note that that are the light years -- the distance that the light has to travel that much. We know that the whole islands on Earth were unreachable for many otherwise common species for millions of years. But these distances are nothing compared with problems of maintaining complex life over the cosmic distances and in the cosmically hostile environment. Also "10-50 million years ahead of us" doesn't have to mean what we think it could mean. For a context, the dinosaurs were, historically, 60 million years "ahead of us". Nobody can "just assume" the we will cross the limits that are ours limits now. Biologically, we did multiply "exponentially" as soon as we were able to use the natural resources to do so (1). But apart from that (the certainty of life using available resources for biological growth), the growth in technical capability for interstellar travel is not guaranteed. Not to mention that the resources are by definition limited. So nobody should ask "why aren't others here" when we can't even claim that we reached somewhere else. What we surely can ask is "why don't we get some signals" because, for example, we are able to send a radio message, but I personally wouldn't assume that the other civilizations make such kind of intentional signalling that we must necessarily be able to detect, being where we are now. It's not "just connect the headset to the wire and a crystal and listen." It's something that has to concentrate immense amounts of energy to reach exactly us. At the moment it's not "is there anybody anywhere" but "is there anybody in the conveniently close neighborhood who's capable to send exactly what we expect to receive, and, most probably, to target exactly in this direction." It's immensely hard to even "see" the planets by the closest stars, that how far everything is. I think that probability for that "targeted messaging" is too low, not to mention that I don't think that the "intelligence" in our sense is inevitably happening on every planet -- we know that from the 3.5 billion years of life on Earth, not even plants existed for 3 billion years. Life can indeed be relatively common but the development that the Earth up to now had could still simply be uncommon enough. 1) https://ourworldindata.org/grapher/world-population-since-10000-bce-ourworldindata-series https://ourworldindata.org/grapher/world-population-since-10...
- philwelch 6y ago
  Given the scale of the galaxy, “we’re early” doesn’t seem all that likely. The galaxy is only 100,000 light years across so even a few million years is likely enough for some signs of expansion to appear. You really think in the entire galaxy, nobody would be 10-50 million years ahead of us? That’s a pretty small margin.
- philwelch 6y ago
  If you’re going to reply to me, please reply to me instead of editing.
  - acqq 6y ago
    > please reply to me instead of editing. Unfortunately, my account has some very, very low limits on the number of replies I can make per day, which I can't influence. Not all users have necessarily the same possibilities, and the privileges one may have aren't universal. My belief is, the limits are there to prevent the discussion progressing too fast and if somebody misses some edit and that even helps the thread remaining slower, maybe the measure still achieved a goal. But I admit it can be confusing. Of course, I'd personally prefer to have at least a bit higher "quota."
Emma_Goldman 6y ago
I'm highly skeptical of a Darwinian argument for galactic conquest. Intelligent societies would, by definition, be determined by non-genetic learning transmitted via culture. Humans are not naturally aggressive anymore than they're naturally peaceful. They have dispositions capable of moving in both directions, the relative strength of which depend cultural socialisation, which is historically variable. I'm not at all sure that, even assuming your estimate, ETI would be 'fairly obvious'. Take some speculative figures. The total area of the milky way is about 30 trillion light years. Let's speculate that intelligent life occurs in one in a million planets. There are something like 100 billion planets in the milky way, so that would be 100,00 planets bearing ETI. If one in a thousand intelligent civilizations are super-expansionary, that comes down to just 100. If we divide the area of the milky way - 30 trillion - by a hundred, we get one super-expansionary civilization per three hundred billion square light years. Would that be obvious? Even if we assume that ETI occurs on average on one in 10,000 planets, that would still be one super-expansionary civilization per three billion square light years.
- philwelch 6y ago
  > Intelligent societies would, by definition, be determined by non-genetic learning transmitted via culture. This is inherently Darwinian as well. In fact, cultural evolution is usually smarter than we are; indigenous pre-industrial cultures typically have an excellent practical understanding of how to thrive in their immediate environment even without having anything close to a theoretical scientific understanding of why their own cultural practices work in the first place. More to the point, cultures that expand and grow, do so at the expense of cultures that don’t. So through natural selection, we would expect to see more expansionary cultures than non-expansionary cultures. And, even setting aside the argument, you still have the much tougher task of explaining the notion that no extraterrestrial cultures are expansionary, which is what your side of this argument would require. > I'm not at all sure that, even assuming your estimate, ETI would be 'fairly obvious'. It would be eventually if it were growing exponentially. On the timescale of the galaxy and by all probability, eventually has already happened unless humanity is an extreme, extreme, extreme outlier early bloomer.
  - 6y ago

acqq 6y ago

> aggressive, exponential expansion is a fairly valid Darwinian strategy. Earth exists for around 4.5 billion years, life on Earth for 3.5 billion years, the whole known Universe just less than 14 billion years (and we can send some small probes to the limits of our own Solar system only during the last decades). So the Universe is not "old" and the distances between the areas suitable for the life to "expand" are immense and real barriers. Knowing the distances involved, I believe that had we discovered that we are in much later age of the Universe, not seeing "others" would mean more than it means now. For now, knowing the distances, whatever could be somewhere far could simply be too far from us, nothing more. Edit: Re: "The galaxy is only 100,000 light years across" note that that are the light years -- the distance that the light has to travel that much. We know that the whole islands on Earth were unreachable for many otherwise common species for millions of years. But these distances are nothing compared with problems of maintaining complex life over the cosmic distances and in the cosmically hostile environment. Also "10-50 million years ahead of us" doesn't have to mean what we think it could mean. For a context, the dinosaurs were, historically, 60 million years "ahead of us". Nobody can "just assume" the we will cross the limits that are ours limits now. Biologically, we did multiply "exponentially" as soon as we were able to use the natural resources to do so (1). But apart from that (the certainty of life using available resources for biological growth), the growth in technical capability for interstellar travel is not guaranteed. Not to mention that the resources are by definition limited. So nobody should ask "why aren't others here" when we can't even claim that we reached somewhere else. What we surely can ask is "why don't we get some signals" because, for example, we are able to send a radio message, but I personally wouldn't assume that the other civilizations make such kind of intentional signalling that we must necessarily be able to detect, being where we are now. It's not "just connect the headset to the wire and a crystal and listen." It's something that has to concentrate immense amounts of energy to reach exactly us. At the moment it's not "is there anybody anywhere" but "is there anybody in the conveniently close neighborhood who's capable to send exactly what we expect to receive, and, most probably, to target exactly in this direction." It's immensely hard to even "see" the planets by the closest stars, that how far everything is. I think that probability for that "targeted messaging" is too low, not to mention that I don't think that the "intelligence" in our sense is inevitably happening on every planet -- we know that from the 3.5 billion years of life on Earth, not even plants existed for 3 billion years. Life can indeed be relatively common but the development that the Earth up to now had could still simply be uncommon enough. 1) https://ourworldindata.org/grapher/world-population-since-10000-bce-ourworldindata-series https://ourworldindata.org/grapher/world-population-since-10...

philwelch 6y ago
Given the scale of the galaxy, “we’re early” doesn’t seem all that likely. The galaxy is only 100,000 light years across so even a few million years is likely enough for some signs of expansion to appear. You really think in the entire galaxy, nobody would be 10-50 million years ahead of us? That’s a pretty small margin.
philwelch 6y ago
If you’re going to reply to me, please reply to me instead of editing.
- acqq 6y ago
  > please reply to me instead of editing. Unfortunately, my account has some very, very low limits on the number of replies I can make per day, which I can't influence. Not all users have necessarily the same possibilities, and the privileges one may have aren't universal. My belief is, the limits are there to prevent the discussion progressing too fast and if somebody misses some edit and that even helps the thread remaining slower, maybe the measure still achieved a goal. But I admit it can be confusing. Of course, I'd personally prefer to have at least a bit higher "quota."

Emma_Goldman 6y ago

I'm highly skeptical of a Darwinian argument for galactic conquest. Intelligent societies would, by definition, be determined by non-genetic learning transmitted via culture. Humans are not naturally aggressive anymore than they're naturally peaceful. They have dispositions capable of moving in both directions, the relative strength of which depend cultural socialisation, which is historically variable. I'm not at all sure that, even assuming your estimate, ETI would be 'fairly obvious'. Take some speculative figures. The total area of the milky way is about 30 trillion light years. Let's speculate that intelligent life occurs in one in a million planets. There are something like 100 billion planets in the milky way, so that would be 100,00 planets bearing ETI. If one in a thousand intelligent civilizations are super-expansionary, that comes down to just 100. If we divide the area of the milky way - 30 trillion - by a hundred, we get one super-expansionary civilization per three hundred billion square light years. Would that be obvious? Even if we assume that ETI occurs on average on one in 10,000 planets, that would still be one super-expansionary civilization per three billion square light years.

philwelch 6y ago
> Intelligent societies would, by definition, be determined by non-genetic learning transmitted via culture. This is inherently Darwinian as well. In fact, cultural evolution is usually smarter than we are; indigenous pre-industrial cultures typically have an excellent practical understanding of how to thrive in their immediate environment even without having anything close to a theoretical scientific understanding of why their own cultural practices work in the first place. More to the point, cultures that expand and grow, do so at the expense of cultures that don’t. So through natural selection, we would expect to see more expansionary cultures than non-expansionary cultures. And, even setting aside the argument, you still have the much tougher task of explaining the notion that no extraterrestrial cultures are expansionary, which is what your side of this argument would require. > I'm not at all sure that, even assuming your estimate, ETI would be 'fairly obvious'. It would be eventually if it were growing exponentially. On the timescale of the galaxy and by all probability, eventually has already happened unless humanity is an extreme, extreme, extreme outlier early bloomer.
- 6y ago