The larger point is that the American Colonies didnt end up staying with the philosophy and structure of the European government. They evolved and had their own justice system, Had a president versus a King, many differences. We did our own thing and rejected the soverenity of the British Crown. Sure we have similar societies, because we were in relatively constant contact with them, and the cultures were close enough in time and space for them to influence each other. We don't have to wait 100 years between communications or travel time in order to have diplomatic relations or compare dress fashions. Thats a huge difference. If we did, how long do you think our cultures would remain similar?

Isaac seems to think (if Interstellar Travel is possible) that the most logical explanation is that there must be a galaxy spanning civilization where all the colonies will systematically control all other civilizations and somehow suppress them from making contact or leaving evidence of their existance, all without a central government or command telling them what to do. WHile its possible, I am arguing that this is implausible and makes too many assumptions. For instance, central control of hundreds of civilizations by one culture would be next to impossible given the huge separation in time and space of the different star systems. I have given examples of Earth cultures, which despite living on the same world and being the same species, we cannot even have that level of control on one planet. Isaac maintains that even in the absence of a civilization dominating the galaxy without having central control (And I dont get how thats possible), this is still the most logical explanation to FP.

They did, and vice versa.

The American Colonies started with the British style of democracy and kept the British style of democracy.
Umm...our legal systems evolved directly from the European systems they came from. For example, in my own home state of Louisiana, our legal system is based on the French system (as opposed to the British system for most of the rest of the USA). It turns out to have the same basics as the one used in Iraq, and as such a lot of Louisiana lawyers have gone to Iraq for their legal experience.
We had a president versus a prime minister, Congress instead of Parlaiment, oooh! Big huge differences!

The bottom line is that we still did the things Europeans did, and for the same reasons. We went with democracy? So did the Europeans! Maybe not at exactly the same time, but we all got there in the end.

We all had the same capitalist ways of doing things, the same mercantile style of imperialism. The same wars of territory and influence.

And it's not just because of common descent. Famously, the Japanese emulated western technology and western styles of government, imperialism, education, economy, and behavior--even down to dress. THAT is what I mean by cultural assimilation.

Now, let's look at what this means for the lack of other civilizations contacting us. According to you, the reason we haven't been sending signals out thousands of light years is because we don't yet have evidence of technological life on any planets out there.

Guess what? It works both ways. Anyone thousands of light years away would not have evidence of technological life here on Earth because we haven't been sending any signals except in the last few decades. All they could see, thousands of light years away, is evidence of a life bearing world (oxygen atmosphere perhaps being a giveaway). Earth would have looked much as it did for billions of years--ever since the oxygen event.

Would we constantly beam signals at an oxygen atmosphere planet thousands of light years away for billions of years, on the off chance that someday it might develop technological life capable of receiving the signal? Or would we just wait for signs of technological life first?

See, if all alien civilizations in the galaxy are more or less like our own human civilization, it's entirely plausible that they wouldn't. Beam signals for billions of years, like that?

Now, if there are thousands or millions of independently evolved civilizations, that have no common mentality and no common descent...then sure. They won't all be human-like and surely at least one of them will just really really really want to signal their existence to the rest of the galaxy, for billions of years, to everyone who MIGHT be out there.

But if there's just one galactic civilization? With common technology, common culture, common ways of doing things, and perhaps even common descent? It would be quite plausible for them to be hard-nosed capitalists like ourselves and use their communications bandwidth for more profitable things like internet porn or reality TV.

King George III was a democracy? Really?
King George III Was a Prime minister? Really?


Yes, but its because they can communicate on a daily basis!!! They can exchange ideas on government, science and fashion daily!!! OF COurse there is some cross cultural influences! we live on the same world.

But, and I want you to address this directly : How alike do you think Japanese and British would dress if they could exchange ideas once every 100 years? NOT AT ALL! Unless now your theory assumes FTL Travel and communication, which makes it even more far fetched than it was.

If two cultures start from the same world, and then colonize 100 LY out, unless there is constant contact, they will become vastly different in a matter of a few generations. ANd my argument is constant contact isnt possible (unless you assume FTL Communications AND travel). ANd without constant contact, there is no ability to centrally control and manage a galactic empire.

OK, Let me further make my point with an analogy. Yes, there are similarities between Nations on Earth, as well as differences. They do live on the same planet, can communicate easily and efficiently, and share some common interests in food morality, and fashion. Why? because there is efficient cultural exchange that can happen very quickly. Japan westernized because they were able to keep up with changes in fashion, laws, governments constantly. Ideas could be exchanged efficiently. So yes, we should see some similiarites. And we do.

However lets apply the same events, but instead of On Earth, Lets assume Great Britian is the home world, and they sent colonists 100 LY to another Planet (US) that their probes said would support them.

The colonists arrive at their new planet after a multi-generation voyage, and they have evolved somewhat because they have adapted to shipboard life and customs. Culture is different because the environment is different. Because of their travel speed, they have had little or no contact with GB. They have lost some of their cultural practices and replaced them with new ones. Some old rituals were no longer possible on board ship, and they were lost , forgotten or evolved to meet their new environment and needs. New holidays and milestones were recognized. A GB Victorian approach to sex did not allow them to ensure that they had enough babies for the next generation, so different views on sex and marriage were adopted. Modesty wasn't possible, so views on personal space and intimacy drastically changed. Work models and ideals of elitism had to be addressed because of the confined nature of the vessel, and the need for everyone to have several professions to run the ship. Ideas on education and emphasis on social connectedness changed to meet the needs of the ship board society as well to adapt to planetary life. Already, a very different culture, and many people are born on the ship who have no rememberance or conscious ties to GB, other than their parents teachings and remnants of GB Culture on the ship. Many GB-ers die enroute.

Then they get to their planet, which isn't the same as GB, it has much more gravity, a different environment, climate is not the same, days are longer, years are longer, seasons all different. No Trees, plant life is a different color. They have struggles to to support their colony that they never had to deal with. back on GB They have to deal with new predators, figure out how to survive. They have to live off the land, eat new foods, create new medicines. They have to deal with a whole world of alien species.

At some point the last true GB citizen dies. They now have ABSOLUTELY NOTHING in common with the environment of their homeworld, and with a 200+ year delay in sending a message and getting a response, NO efficient or reasonable cross cultural exchanges or influences can be had.

Now Issac, please tell me how, in such radically different environments how these colonists, who are over 100 years removed from the original home, and who NO have reasonable ability to communicate efficiently with GB, incuding NO cultural exchanges, and with completely different planetary environments are going to keep their Identity (no cultural evolution) as GB'ers over the next few generations? I'd suspect that within 2 generations you wouldnt be able to tell they were from the same home planet, except for they were the same species. Within 5 generations, their physical attributes would be very different, due to differences in climate and gravity, solar radiation, any number of environmental pressures that are different. Standards of beauty, morality and society would be unrecognizeable from one culture to the other.

Oh, Unless they only settle planets that are EXACTLY like GB, and have FTL technology, which is another set of assumptions that makes your "easy" answer all the more far fetched.

Yes. But we have been sending out radar signals since the 40's, and TV signals from the 1920's - about just recently.

Spectroscopy could reveal drastic changes indicating a technological civilization for the past 150 years. FOr one example. Its not just radio signals that could reveal us.

that's not the only method by which we could be detected, especially once we leave the solar system. You are talking about a galaxy wide civilization which is controlling many others. they'd leave much more evidence than we.
We havent left much evidence other than a few signals and spectroscopy.

again, beaming signals is not the only way to leave evidence. And I have said before, evidence donest have to mean they are purposefully sending signals. Advanced galaxy spanning civilizations will leave traces whether they want to or not.

yes, but you say that One will be dominating all of them, and controlling them so they wont give away their presence. Not all of them will be human like, there is no reason to think so.

If there is Earth, and One other, it stands to reason there are at least a thousand. 1 civilization I could accept. 2 I cant. If there are two, then Advanced life isnt special, and would arise more frequently. Impossible? No. Highly unlikely. 1 is an anomaly. 2 is a pattern.

At the time of the American Revolution, Britain was a democracy. This was well after the British Civil Wars and the English Bill of Rights.
They would still wear clothes, because they're still humans, and I'd bet that these clothes would cover up the genitalia. Because they're still humans with human sensibilities and hangups.

Again, you fail to consider that the similarities between humans far outweigh the differences.
Which would be quite invisible to any civilization thousands of light years away. This information would only be relevant to civilizations within 75 light years from us. (75 years for the information to reach that civilization; another 75 years for their signals to reach us.)

But why would they send a signal just because there was evidence of, large scale burning of carbon compounds? That's really not very good evidence of technology, and even if it is evidence of relatively primitive technology it's not evidence of the sort of radio technology required to receive a radio signal.

Suppose a civilization 75 light years away detects evidence of large scale coal burning on Earth. They guess that this might mean there is primitive technological life on Earth. So what? They don't know how long it will be before Earthlings develop radio technology. Maybe another hundred years...maybe another thousand years...maybe another million years. Why start sending signals until there's evidence of radio technology?

BTW, the sort of radio signals we've been sending out so far would be hard to detect even four light years away, much less 75 light years away.
It is just radio signals that would reveal that we're worth beaming radio signals to. Assuming the aliens have cost/benefit economic sensibilities vaguely similar to human sensibilities.

you are completely failing to address my points.

You contend that the most logical conclusion to FP (if Interstellar travel is possible) is that One civilization has become dominant over all others, and they are actively surpressing all other civilizations so that we can have no evidence of them.

They do this through Genocide, resource depletion, cutural dominance, and threats of war.

They do this even though the worlds are separated by hundreds or thousands of light years, and no central government or formal control is in place. Communication delays are measured in hundreds of years, or thousands.

they do this despite contending with differenting races, planetary environmnets, languages, philosophys, and all the other differences that are possible between alien species.

Colonies from this dominant civilization all act according to their original philosophy and systematically destroy or control all civilizations they come into contact with, despite not being able to communicate or coordinate their efforts with their homeworld. Its ingrained into their very being to prevent these other civilizations from making contact, and to supress them at all costs.

ANd, Dominant Civilization Colonies undergo no social evoloution or progress independantly despite no contact with thier homeworld. Therefore they dont change from their home culture and hence always carry out the goals of the home world by ensuring no other civilizations will makie their presence known to us in any number of ways. WHich is very convenient.

Oh, and now, after going through all this trouble with building this dominant civilization, you change tactices and start arguing that all those civilizations arent interested in contact us anyway, or they cant?


are you sure this is the position you want to defend, or has it changed again?

No. I list many possibilities. Among them is the possibility of active suppression, but it's not the only one.
No. Those are a list of many possibilities. As I have always noted, there are many possibilities.

You are confused because you are conflating them all into one, even though that makes no logical sense. Many of those possibilities are mutually exclusive! If the dominant civilization simply exterminates everyone else, does it make sense for them to also be making demands on them? No--either they are implacably genocidal or they aren't.

You Said:

(my emphasis)

your argument from then on was that this was the most likely scenario, given Interstellar travel.

Here you forward that this one dominant civilization MUST have wiped out all others, which assumes they had a giant head start, and got to every other star system in the galaxy, and not one other one was able to rise up. This a a gigantic assumption, I dont see how you can defend it with a straight face.

(by the way, why havent they wiped us out yet?)

Then when I brought up that there would likely be many civilizations, that it would be impossible to wipe them all out and ensure no others were around, you argued this Dominant Civilization Suppressed them so they couldnt Make contact. Youl listed many means by which they could do this.

When I argued that these civilizations would be spread out over thousands of light years, and live in many different environments, you then said this dominant race Only targeted planets very like their own, ignoring anything different. Which contradicts your dominant civilization supressing all others, and it excludes space faring civilizations from arising on any home worlds that differe significantly from their own.

When I argued that colonies (thousands of them) of this dominant race would evolve on their own and given hundreds of years delay between communications, they would be so different than their original race that they'd likely to have different motivations and drives, and would therefore be unlikely to carry out this goal of supressing all other civilizations, you counter that they wouldnt evolve or the prime directive was so ingrained in them they didnt need contact or central control.

Then you argue that we couldn't detect them anyway, despite there being thousands.

Then you argue there is only one race, and there is no reason for them to contact us.

Then you argue that your dominant civilization was only one of many possibilities, in direct contradiction to your original post on this matter.


You only address those items you can defend, which aren't central to your argument.

DO you still agree with your original assertion, or not? Why is it the easy answer? I think its an answer with one heck of a lot of assumptions.

It looks as though this is becoming iquestor's paradox, no?

The debate in itself is quite interesting, but it's starting to get a bit repetitive.

I think both of your points of view are pretty clear by now,
no need to continue nitpicking about what the other said 15 posts ago or not

LOL ! Agreed.

I collect answers to the Fermi Paradox; this is a new one (I think), and perhaps we can sum it up to make it a bit clearer.

Let's see; there is no evidence of extraterrestrial civilisation because a single, ancient civilisation has established itself and suppresses all others, but is itself undetectable because it occupies an (unspecified) environment which we have not yet examined in detail.

Is that it?

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Thats my take on Isaac's stance. Personally, I think it relies on too many assumptions.


I like the following answers:

1. No viable FTL + Rarity and sparse distribution of space civilizations + lack of coincidence in civilizations existing at required levels of tech at the same time in the same vicinity.

2. all the old civilizations are now machine intelligences and we aren't interesting to them or beneath notice; Any new organics civilizations aren't advanced enough and lack ability of interstellar travel / contact in order for us to detect them.

This assumes older machine intelligences aren't constructing type 2 or 3 projects (Dyson Spheres, etc), which presumable would be detectable by us.

No, it's too complex.

My solution, basically, boils down to this:

They simply haven't contacted us yet.

This solution fails if there are millions of independently evolved civilizations out there with no shared technology or knowledge or sensibilities. If there are millions of independently evolved civilizations, then surely at least one of them is crazy enough to beam signals at Earth for billions of years despite the lack of any evidence of radio technology.

But if there's just one dominant civilization, with shared technology and knowledge and sensibilities, then it's entirely plausible that none of them will bother beaming signals at Earth until after they see evidence of radio technology.

As for US detecting THEM? We haven't detected them yet but that's entirely unsurprising given our limited efforts so far. We haven't examined ANY other star systems sufficiently well to detect life, much less technological life.

There's no plausible way for us to have detected them across interstellar distances, except via signals specifically beamed at us. Interstellar propulsion systems, as powerful as they would be, would be hard to detect more than a few light years away. The only plausible way for us to have incidentally detected them would be if they used Dyson spheres, but there are any number of plausible reasons why they wouldn't make Dyson spheres.

Isaac, considering your argument that a civilization probably wont engage in CETI for lack of a good compelling reason ( I also agree with this) -
AND we'd only pick up signals that were directly beamed at us due to the need for a hi energy but tightly focused beam, Then Why do we earthlings spend so much time on SETI (and so little on CETI)?

WHat is the rationale? DO our SETI Scientists feel differently about the above scenarios, or do they disagree?

Do they think its likely we could evesdrop on ET if they werent targeting us for a communications target?

DO they think ET will think we are a likely target? I don't think so. As it has been pointed out, there has really only been a period where we are sending out signals that could be considered intelligent from 1940 to present, and much of this is going away as TV is digital and military rader systems are higher frequency, more directed, and more efficient, thus less noisy to space.

or is it just that we can listen on a billion channels and cover a wide area, so we are looking for the odd signal in a haystack?

(question of course open to everyone. )

SETI asks a scientific question, and we wouldn't know the answer to this question without at least looking.

Rather than merely speculate about whether aliens are trying to signal us, SETI asks the scientific question--ARE they trying to signal us? It's a legitimate scientific question which deserves a scientific answer. And we do science by making observations.

Now, you have to remember that when SETI was started, we knew a LOT less about the universe around us. We didn't even know whether other star systems had planets, much less what they were like. At the time, the only possible way to look for evidence of ET life was to look for ETI signals beamed at us. Based on what we knew at the time, SETI was simply the only conceivable shot we had at detecting alien life. It was perhaps a longshot, but we wouldn't know until we tried.

In the decades since, we have begun detecting exoplanets and even started characterizing the atmospheric properties of some of them. We have a lot of other scientific options to try and detect alien life. That doesn't mean the SETI experiment has to cease, though. We've only been looking for a signal for a few decades. What if the aliens are beaming the signal to different star systems in turn, and we'll have to wait a hundred years before the next time they get around to us? SETI is still asking a legitimate scientific question, and it's still worth at least looking.

CETI is harder to justify on scientific grounds. The problem is time. Even if CETI is successful, it will be many years before we get the scientific payoff from it. Depending on how far away the target system is, it could be many decades or millenia.

Also, CETI is somewhat controversial on political grounds. There's a human worry that successful CETI would alert potentially hostile aliens to our presence. Whether this fear is justified or not, it is a fear which is natural for us humans to have. SETI will not affect whether or not hostile aliens detect us; while CETI might.

And then there are practical grounds. CETI costs more, per signal. Receiving a signal costs little compared to sending a signal strong enough to be received across interstellar distances. A handheld radio costs less than a radio transmission tower.

Well, if there is an ancient, non-communicative civilisation out there it should be able to detect our biosphere, and will have been able to detect our biosphere for the last half a billion years at least. That is why it might either want to contact us or suppress us. It will have known about us for half a gigayear.

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Sure, but they might have "contacted" us during the time of the dinosaurs. They might even have popped by, studied the dinosaurs, said hi to the velociraptors...and then left after a few million years when they had enough of our biosphere for the time being.

My point being--even if they had detected "us" billions of years ago, would they have remained interested in "us" for billions of years? Maybe, maybe not.

There are so many different possibilities. Maybe they are already familiar with many biospheres like our own. Maybe they don't care--maybe they aren't even looking for biospheres. Maybe they are interested in our biosphere and are observing us even now, but for whatever reasons they don't interfere with us. Maybe the ARE interfering with us, but they'd rather secretly influence us. Maybe not.

Another maybe...

Maybe they're only about 100 years ahead of us. They have detected our life-capable atmosphere by spectroscopy and have dedicated radio telescopes aimed right at us. We're just not transmitting anything convincing.

They could even be transmitting themselves, but not in a way that's managed to catch our attention yet.

Yep; and Cirkovic (and G.David Brin before him) have managed to list quite a few of them.

I like this one; the 'we are nothing special' possibility. The universe might be so jam-packed full of biospheres that ours is easy to overlook.

Something tells me that it is not correct, however. Perhaps the fact that all the other planets in our solar system are so inhospitable suggests that the vast majority of other worlds and systems are lifeless. But that may be too pessimistic an conclusion.

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That makes me think of another possibility:
if planets with biospheres were relatively common, there would probably also be quite a few systems with several biospheres.

So why would anybody pay special attention to a system like ours, where there is only one biosphere to study?
(and not yet any detectable sign of civilization - unless you happen to be in the immediate vicinity)

This makes sense if biospheres are relatively common. What if they're somewhat rare? Would it not make sense in that case to point your instruments at every biosphere you find "just in case" one starts to show signs of life?

If in the future we manage to find, say, 5 planets with atmospheres capable of supporting life as we know it, I'd predict that each of those planets would have its own dedicated array of instruments pointed at it continuously.

Here's an interesting piece on Fermi's look into space-time...

http://www.nasa.gov/mission_pages/GL...irst_year.html

iquestor knows all of this! No more postulation necessary.

Fermi's paradox is more like Fermi's simple question. Many simple answers have been given. A combination of them looks like a reasonable explanation: Distance (both in space and time), lifespan of civilizations, etc.

It's ironic that the same vastness of our galaxy that gives good odds for intelligence occurring more than once also gives poor odds for proving it. Depressing, but true.

No need to stop trying though. I like the direction we are going in of identifying Earth-like planets, then identifying those which have suggestive atmospheres, then specifically listening to and signaling those. Still, seems like slim odds of success.

Is there a smell of sock in the air?

Anyhow, there indeed most likely isn't a single solution to FP but instead a number of factors conspiring against us finding actual company, or even just not-of-this-Earth-mouldy rocks.

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OTOH, when I started to develop an interest in astronomy (in the late 70s/early 80s),
I never thought I would witness the confirmation of exoplanets.

And now we are already beginning to analyze the composition of their atmospheres!

A good illustration of one of the answers to Fermi's question.

I think some of the points that we need to consider is how the vision of other civilisations, SETI contact design, Kardashev scale are based in XX century thinking and reflection of views and ideologies of human civilisation at the time.

The idea that civilisations must go into a phase of building megaprojects doesn't seem to be valid, it's completely imaginable that they could be viewed as too costly, require too much organisation and essentially seen as castle in sky ideas that nobody would be willing to pursue or realise. To me they resemble the spirit of engineering Earth so common among scientists of XX century who proposed diverting rivers, creating artificial harbours from nuclear blasts, making farmland out of deserts. Those ideas were possibly extrapolated into a vision of what the future would bring.

However we already see that it is also for a civilisation to pursue a conservative path, puting more focus on keeping the natural habitat unspoiled and in untouched state(I would like to remark that it is not my belief)-so it could be that due to those views some civilisations never bothered with mega projects at all and kept a more exploration type of activity during their existance rather then interventionalist.


If such a civilization would visit Earth in the past, it is no surprise it left no signs at all-it would be more concerned in letting our world develop itself in normal pace without any interference.



As to contact with us-similar action is pursued by our own civilisation right now in cases of isolated native tribes-we came to a point where it is believed its better not to contact them as their way of life would be highly disturbed. If any civilisation exists and is in contact with us(which I doubt) then such a course of action is completely plausible.


The problem is that dogma coming from XX century demands all civilisations to be very expansionistic, engaged in mega-engineering, and manipulation of the galaxy. We already see that our own civilisation develops trends for conservation, non-interference-it could be that any civilisations that existed simply traveled as explorers or focused inward. And as intelligence is unique in our habitat then we can assume those civilisations were few.



Why only those two options ? It might very well simply observe us. It would a wise path, since contact with much more advanced cultures leads to destruction of the less developed ones quite often. And we are talking about culture possibly developed in milions of years. Heck, I guess if we would discover developed Stone Age civilisation in Alpha Centauri after travelling there, there would be serious voices NOT to contact them.



My personal view-they were very few civilisations in our galaxy, perhaps you could count them on fingers of your hands. All of them eventually focused inward and passed away or are in virtual-like state. From those only a couple discovered remains or traces of another, the distances involved usually meant they never discovered each other's existance, and contact with any relic of said civilisation would be destructive to lesser culture. We are in effect alone in Galaxy, in time we may discover some traces of a couple of unfinished mega projects but this it. If we are lucky perhaps some ruins or derelicts that will mess with our heads and culture. We will discover life but most of it primitive bilions of years behind us, with a rare occasion of one or two having chances of evolving into intelligence, which we will leave alone.

The problem with "soft solutions" to the FP tends to be that they usually, like in your example, assume a fairly uniform mindset over all the existant civilizations. Depending on how far off we would actually be able to detect higher Kardashev scale macroprojects, it would take only one single civilization who happened to be seriously affected with delusions of grandeur to "blow the whistle" for example. The more aliens one assumes there are, the more likely it would become there's such a fluke among them. So assuming five might work, assuming fifty not so well.

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