1. If an advanced alien civ discovers a nearby advanced civ, the probability there's another nearby advanced civ increases dramatically. — RogueAI

I don't see why this is necessarily so.

2. It follows from (1) that the probability of there being a more powerful nearby alien civ also increases.

Again - I don't see why this is so.

3. Advanced alien civs are likely to be keeping an eye on things in their local neighborhood.

Maybe, but it's based on a couple of assumptions I don't necessarily think are valid.

4. Therefore, advanced alien civs that come in contact with each other have to assume it's very possible a more advanced civ is observing how the interaction plays out. They have to think it's entirely possible they're playing to an unseen audience.

Again, this is based on assumptions I don't necessarily think are valid.

5. Planets are sitting ducks, and it would be trivially easy for a powerful advanced alien civ to accelerate an asteroid/comet/swarm of projectiles to, say, 10% the speed of light, and hit your planet with it. Powerful advanced alien civs, therefore, are potential existential threats.

Ok.

6. Existential threats are to be avoided at all costs.

Yes.

7. Acting aggressively increases the probability that an unseen powerful alien civ would respond negatively to such aggression.

Maybe

8. Non-aggression, therefore, is the best strategy, if continued survival is a high priority.

I think it's true, but I don't see that it follows from the chain of logic.

I don't see why this is necessarily so.

If there are only two advanced alien civs in the entire galaxy, it would be extremely improbable they would find themselves near each other. The same is true if there were only three, or four, or five...therefore, if you run into an alien civ, you can conclude there are probably quite a few in the galaxy, which leads to the conclusion that, if you've stumbled across one nearby civ, there's a good chance there's at least one more in the local neighborhood.

There might not be, of course, but if you don't know that, and if you haven't done a real exhaustive search, you have to assume there might be someone observing you.

Again - I don't see why this is so.

If probability "alien life exists" increases, then probability "alien life more advanced than me exists" also increases. Unless you have a priori reasons for discounting the possibility of more advanced alien life existing.

Maybe, but it's based on a couple of assumptions I don't necessarily think are valid.

They are safe assumptions, though. An advanced alien civ is going to be concerned with self-preservation, and will have the technology and means of sending probes to investigate nearby interesting planets and keep tabs on any of the life forms on them. I don't think the "art of war" will be any different for aliens than they are for us, and one of the first principles is "know your enemy".

I posted a long reply, went to edit it, and the whole thing disappeared.

"I don't see why this is necessarily so."

The probability the only two advanced species in the galaxy are near each other is very low. Therefore, it's probable there are more than two advanced species in the galaxy. If you run into a nearby one, you can conclude there are probably a lot, which raises the possibility of one nearby you.

"Again - I don't see why this is so."

If the probability "advanced alien life exists" increases to essentially 1, then the probability "alien life more advanced than me exists" also increases.

"Maybe, but it's based on a couple of assumptions I don't necessarily think are valid."

They're safe assumptions. An advanced alien civ is going to be concerned with self-preservation and will have the tech and means to send probes out to nearby interesting planets and keep tabs on any lifeforms there. The art of war won't be any different for aliens, and a first principle is "know your enemy".

I posted a long reply, went to edit it, and the whole thing disappeared. — RogueAI

Yeah, I read your first post but didn't respond right away.

The probability the only two advanced species in the galaxy are near each other is very low. Therefore, it's probable there are more than two advanced species in the galaxy. If you run into a nearby one, you can conclude there are probably a lot, which raises the possibility of one nearby you. — RogueAI

This doesn't make any sense to me.

If the probability "advanced alien life exists" increases to essentially 1, then the probability "alien life more advanced than me exists" also increases. — RogueAI

Ok, but I don't get the rest of your inference.

They're safe assumptions. — RogueAI

I don't think so. They seem more like fantasy to me.

An advanced alien civ is going to be concerned with self-preservation and will have the tech and means to send probes out to nearby interesting planets and keep tabs on any lifeforms there. The art of war won't be any different for aliens, and a first principle is "know your enemy". — RogueAI

I don't know that this is incorrect, but I don't have any reason to believe that it's true. I don't think you know either.

I don't know what will happen if we ever come in contact with an intelligent non-human species. My first take is that, since, as far as we can tell, faster than light travel is not possible, we won't have much to offer each other and probably won't have much reason to be a threat to each other. I'm certainly not sure of that, but it seems more likely than the scenario you have laid out.

This doesn't make any sense to me.

When two alien civs discover each other, each will have to deal with the following disjunctive proposition: "Either there are only two advanced races in the galaxy who happen to find themselves right next to each other OR there are more than two advanced races in the galaxy". They can't both be true, and since the probability "two advanced races in the galaxy happen to find themselves right next to each other" is exceedingly unlikely, the disjunct is therefore exceedingly likely: "there are more than two advanced races in the galaxy".

If you postulate there are THREE advanced species in the galaxy, you run into the same problem: it's exceedingly unlikely that two of the three only advanced races are right next to each other. The same is true if you postulate there are FOUR advanced species in the galaxy. What are the odds that two of the four would be right next to each other? And so on...Eventually, you'll conclude there are a lot of advanced species in the galaxy, and you just met your neighbor and it's almost a given there are more neighbors.

It is possible, of course, that the only two advanced species in the galaxy are right next to each other. It's also possible to win the lottery. It's almost certainly not going to happen, though.

I don't think so. They seem more like fantasy to me.

It's fantastical that advanced aliens would be concerned with self preservation, would be curious about what's around them, and would send out probes? You think those are fantastical assumptions? Really? I think they're rock solid. Aliens are going to be under the same evolutionary pressures everyone else is, and if you have clawed your way to the top of the food chain, it was a long hard slog. In their history, they would have had to fend off competitors and predators and they would be well aware of the dangers an unknown alien race poses.

Remember, all this is happening with the background knowledge that biospheres are fragile, planets are sitting ducks, and accelerating course-correcting projectiles to ram into planets at high speeds is not that hard.

The probability the only two advanced species in the galaxy are near each other is very low. Therefore, it's probable there are more than two advanced species in the galaxy. If you run into a nearby one, you can conclude there are probably a lot, which raises the possibility of one nearby you.
@RogueAI

This doesn't make any sense to me. — T Clark

Makes sense to me. Independently evolved advanced species in close proximity supports a prediction that the population of advanced species in the galaxy is relatively large (relative to a scenario where distances between advanced species is great). With a large population and without evidence that our civilization is more advanced than the norm, it is reasonable to expect other advanced civilizations in the vicinity and that the distance to the nearest civilization more advanced than us is relatively short.

Brings to mind a comment on the Great Filter as a solution to the Fermi Paradox.

This is why Oxford University philosopher Nick Bostrom says that “no news is good news.” The discovery of even simple life on Mars would be devastating, because it would cut out a number of potential Great Filters behind us. And if we were to find fossilized complex life on Mars, Bostrom says “it would be by far the worst news ever printed on a newspaper cover,” because it would mean The Great Filter is almost definitely ahead of us—ultimately dooming the species. Bostrom believes that when it comes to The Fermi Paradox, “the silence of the night sky is golden.”

For those who find the Great Filter hypothesis compelling, I expect the greater the distance to the nearest extinct extra terrestrial life the better.

No, I don’t think going by a strictly probability based method is the BEST strategy. Its A strategy, but it will always better to make a data based decision. These aliens would be much better off if they kept looking after finding a nearby habited planet, to make sure they don’t have to worry about bigger badder aliens interfering.
And what other data would be helpful? Whats the first planet like? Worth conquering? Is trade a better option if there is a resource they need?
The wisest approach is never just a probability calculation.

For those who find the Great Filter hypothesis compelling, I expect the greater the distance to the nearest extinct extra terrestrial life the better. — JosephS

Certainly an interesting take on the subject. Though I wonder if that isn't a case of gambler's fallacy.

I don't have any opinion one way or the other, but you might want to check this alternative approach: Dark Forest Theory

I don't have any opinion one way or the other, but you might want to check this alternative approach: Dark Forest Theory

Yeah, that was a great series. It's not very likely, though. If the galaxy was full of hyper-paranoid aliens, they wouldn't need to wait for the coordinates of planets to be broadcast to destroy them. For the past 500+ million years, any nearby aliens with a fairly large telescope would have concluded it's highly probable there's life here, and, if the aliens are paranoid, they would have taken us out early on.

Also, we have the same problem I presented in the OP: if you're going around destroying everything in sight, you're taking a huge chance. Anyone more powerful than you observing that kind of aggressive behavior is going to be extremely concerned about it.

In that series, the best strategy for the humans and Trisolarians was cooperation. ***Spoiler*** The strategy of extreme paranoia that both sides adopted didn't work out well for them in the end.

No, I don’t think going by a strictly probability based method is the BEST strategy. Its A strategy, but it will always better to make a data based decision. These aliens would be much better off if they kept looking after finding a nearby habited planet, to make sure they don’t have to worry about bigger badder aliens interfering.
And what other data would be helpful? Whats the first planet like? Worth conquering? Is trade a better option if there is a resource they need?
The wisest approach is never just a probability calculation.

Everything's a probability calculation. You can never have complete certainty about the external world. That's why poker is so fun.

You do not need complete certainty to consider data. If you think everything is a probability calculation then you do not understand probability.
Depending on how you like to frame things about probability, this example might need tweaking but it should illustrate my point regardless.
Take classic three card monty, a queens and two kings are put face down on the table. The dealer shows you the queen and then rapidly moves the cards around, mixing them up until its not clear which is the queen. You must guess which is the queen.
So, you have a 1 in 3 chance to be right. Over time, you will get roughly 1 out of 3 guesses correct simply by playing the odds. That is indeed one way in which probability can give you a fairly reliable prediction. Is it the best way? No.
Lets think about the dealer. He has the best data set for determining where the queen is, he is the one that put it where it is, he has alot of experience tracking where the queen is, he may have the queen marked somehow etc etc.
Lets just grant you that your probability calculation is 100% reliable. You will ALWAYS get 1 out of 3 when guessing where the queen is.
Who do you think will make more accurate “guesses” about where the queen is via superior method? Obviously the dealer. If you don’t think so, go play some 3 card monty and see how much money you make off the dealer. The same goes for poker btw. If you play the odds over computing data, you will end up losing all your money.
So, data based decisions are superior to probability based decisions, unless of course there is no data to go on.
Is cooperation the BEST strategy, based on probability? No. Probability is not the best as data based is obviously superior. Is data based the best? Maybe...its possible you can present something superior to it...but its not the probability based argument you offered.

I'm not sure of your concern with the gambler's fallacy.

From Bostrom's paper:

What has all this got to do with finding life on Mars? Consider the implications of
discovering that life had evolved independently on Mars (or some other planet in our
solar system). That discovery would suggest that the emergence of life is not a very
improbable event. If it happened independently twice here in our own back yard, it
must surely have happened millions times across the galaxy. This would mean that the
Great Filter is less likely to occur in the early life of planets and is therefore more likely
still to come.
If we discovered some very simple life forms on Mars in its soil or under the ice at the
polar caps, it would show that the Great Filter must exist somewhere after that period in
evolution. This would be disturbing, but we might still hope that the Great Filter was
located in our past. If we discovered a more advanced life‐form, such as some kind of
multi‐cellular organism, that would eliminate a much larger stretch of potential locations
where the Great Filter could be. The effect would be to shift the probability more
strongly to the hypothesis that the Great Filter is ahead of us, not behind us. And if we
discovered the fossils of some very complex life form, such as of some vertebrate‐like
creature, we would have to conclude that the probability is very great that the bulk of the
Great Filter is ahead of us. Such a discovery would be a crushing blow. It would be by
far the worst news ever printed on a newspaper cover.

My contention that the farther away the better derives from Bostrom's concerns around finding independently arisen, extinct life in our backyard. Farther away correlates to a lower rate for life developing in the universe and perhaps a better chance that we are, indeed, the outlier.

So, you have a 1 in 3 chance to be right.

How do I know the dealer's not cheating?

https://plato.stanford.edu/entries/probability-interpret/#SubPro

You dont. Thats part of my point. He could be cheating, and the probability might not kick in at all. Remember I mentioned the marked card? Thats data the dealer has and its more effective by far than probability.
Likewise, the aliens are BEST served by gathering data, finding out more information etc, unless you can offer a better one because as I said, probability is not.

I know yours was probably a rhetorical question but I would, after a sufficient number of iterations, see if the measure of likelihood supported the claim that the dealer was almost certainly cheating me.

https://stats.stackexchange.com/questions/2641/what-is-the-difference-between-likelihood-and-probability

Did I win? :-)

"You dont. Thats part of my point. He could be cheating, and the probability might not kick in at all."

Probability always kicks in, that's why I linked to an article about subjective probability. Before I play any card game, I'm going to assign a subjective probability to the hypothesis: "the dealer isn't cheating".

I don't understand the point you're trying to make.

I skimmed over the post you replied to. I figured your question was around detecting a cheating dealer. I remember doing something akin to this that involved Bayesian likelihood measurement to conclude whether a die was fair or unfair.

I read again the post you replied to.

Personally, I can't make heads or tails of it, but I doubt my post is relevant.

Regardless, I think your contention that everything is a probability calculation holds significant weight, interpreted as a reflection on subjective probability and its relationship to belief.

I do love me some Bayes. Not everyone is a Bayesian, though, so maybe that's where DingoJones is coming from.

My knowledge is tuned to practical application vs having internalized the implications of a Bayesian perspective. Until I came to grips with the nature of subjective probability as reflective of belief (and why a Bayesian probability for the existence of extra-terrestrial intelligence makes sense), I was utterly confused.

Honestly, and I suspect its due to my relatively late learning, using the same term, probability, for both frequentist as well as Bayesian measures, frustrated my learning process. I kept expecting the concepts to meld into a powerful, abstract union. At some point I learned just to pocket them separately in my mind.

Your not listening/addressing what Im saying.
You assign your probability that the dealer is cheating, Ill gather data on how cheating is done, and the possible ways he could be cheating and then correlate that data with what the dealer is doing and how he is doing it. Who will more reliably detect cheating? Me, for the reasons I explained.
Understand? The aliens could go by the likelihood of there being a nearby, more advanced species or they could look and see if there is one. Whether or not there actually is a more advanced alien is not effected whatsoever by what probability dictates.
Data based is superior to probability based. If it helps, I will concede (again) that in situations where no data is available, probability could be the best basis...its just not the case in the scenario you laid out.

Have you met an alien?

Who me?

When two alien civs discover each other, each will have to deal with the following disjunctive proposition: "Either there are only two advanced races in the galaxy who happen to find themselves right next to each other OR there are more than two advanced races in the galaxy". They can't both be true, and since the probability "two advanced races in the galaxy happen to find themselves right next to each other" is exceedingly unlikely, the disjunct is therefore exceedingly likely: "there are more than two advanced races in the galaxy". — RogueAI

Makes sense to me. Independently evolved advanced species in close proximity supports a prediction that the population of advanced species in the galaxy is relatively large (relative to a scenario where distances between advanced species is great). With a large population and without evidence that our civilization is more advanced than the norm, it is reasonable to expect other advanced civilizations in the vicinity and that the distance to the nearest civilization more advanced than us is relatively short. — JosephS

You two talked me into it. I think you're right.

Ah, but suppose there is something unique to our little sector of the galaxy which makes it the only habitable place for advanced life. In that case, two alien civs bumping into each other wouldn't seem so remote. Is this little patch of the Milky Way we're in that special?

Ah, but suppose there is something unique to our little sector of the galaxy which makes it the only habitable place for advanced life. In that case, two alien civs bumping into each other wouldn't seem so remote. Is this little patch of the Milky Way we're in that special? — RogueAI

No, you've misunderstood how things work on the forum. Here's the way it's supposed to work - You tell me I'm wrong, and then I make up lame excuses why I'm right after all.

To be clear, I share your skepticism for what remains of the logical chain from the first post. Maybe non-aggression ends up being the best strategy, but it sounds like the beginning strategy rather than a consistent practice over time.

It sounds particularly foreign in comparison to how human history has played out.

Ah, but suppose there is something unique to our little sector of the galaxy which makes it the only habitable place for advanced life. In that case, two alien civs bumping into each other wouldn't seem so remote. Is this little patch of the Milky Way we're in that special?
— @RogueAI

No, you've misunderstood how things work on the forum. Here's the way it's supposed to work - You tell me I'm wrong, and then I make up lame excuses why I'm right after all. — T Clark

My mom says I'm special. I suggest that makes our little galactic neighborhood special, by implication.

I think the differences between us and an alien civ can be so vast that making predictions like these would be completely meaningless no offence