Simulations and the Fermi paradox

If we are living in a simulation, does that resolve the Fermi paradox?  I would think so.  The “aliens” would be here, we just would not “see” them as such.  But in fact we would be looking at nothing but the alien products, namely the creators of the simulation.

Should we expect to find alien civilizations in a simulation?  The priors are not so clear: do the simulation creators want full Bayesian realism?  Is the universe run by an alien version of Daniel Kahneman?  The simulation has not excluded animals, but it has (so far) excluded self-replicating von Neumann probes or the use of supernovae as alien corporate advertisements.  The simulation still might have alien civilizations turn up in ways which do not make Bayesian sense, but which add to the drama.  For the time being, we are still in a “no aliens” do loop.

I thank Jim Olds for a conversation related to this topic.  In any case, the Fermi paradox raises the likelihood that we are living in a simulation.

Addendum: Robin Hanson comments, as does Jim Olds.


If the "aliens" are God, and the "simulation" is the universe, then that is merely the reality that most religious people believe we are in.

Whether the dearth of observed aliens is because God actively smote them or because He turned the dials so that one galaxy out of a hundred -- or one universe out of a hundred -- sees an intelligent species make it through the filters is an open question.

To say that this is what religious people believe in is a bit of a stretch.

For example, there's no evidence that the simulators, should they exist, are interested in people, actively intervening in anything, or "good."

Fair enough. Replace "religious people" with "people who believe in God" or, more generally, "people who believe some external consciousness created the universe".

You pretty much have to remove the word "God," I think, since there's nothing supernatural in this explanation.

If "natural" is "everything in the world," then "something beyond the world which created the world" would pretty much be "supernatural." :)

Philosophical question: if God exists, does He regard Himself as natural or supernatural?

Heh heh. I yield to your quibble.

I was thinking of "explainable by science" as pretty much the opposite of "God."

It only solves the Fermi paradox if we're in single-player mode. If we want to meet other civilizations, we may need to buy the expansion pack.

Sure, there are universal laws, laws that apply in every possible universe. And one of them is that eventually you must pay for the expansion pack.

The Fermi paradox doesn't account for the distances involved in exploring the universe. There's a unstated feeling in science fiction that fast-than-light travel is simply an engineering problem; i.e., once we understand the physics more fully, we'll be able to travel around Star Trek fashion where ever we want, but it may very well be an insurmountable mathematical certitude. In which case the time and energy necessary to explore the universe may make actual physical contact with an alien civilization vanishingly improbable.

We are just on the verge of having telescopes that will be able to detect evidence of biological processes on other planets directly, extraterrestrial life may be discernible, although any potential two-way communication virtually impossible in human timescales.

Interstellar travel doesn't have to be just hard, given the numbers, it has to be essentially impossible. Which most people agree is just implausible - interstellar travel looks reasonably tractable, at least for von Neumann probes. It might be impossible, but it's a much greater intellectual leap than more conventional explanations.

>The Fermi paradox doesn’t account for the distances involved in exploring the universe

In the Drake equation, fc = "the fraction of civilizations that develop a technology that releases detectable signs of their existence into space". Travel is not required.

As a general rule, if you think you've spotted an elementary mistake by someone like Fermi you should reconsider. In this case, you need to compare interstellar distances with the time available (some fraction of the age of the universe).

+1, if you factor in the time scales, then the speed of light is a trivial barrier. i.e 1% of the speed of light is more than enough time to have probed the entire Galaxy 100 times over.

This implies a level of coherency of purpose and effort that I just don't think is maintainable across the time periods involved.

Not when you assume self replicating Von Neumann probes.

Hmmm, maybe after a few billion years a life form evolved that lives in Oort clouds and eats probes. Perhaps, Sol is being bombarded by probes continuously but the never make it past the buffet line.

+1 for JWatts

This is commonly referred to as the "Berserkers" resolution of the paradox, and it's both unpleasant and consistent with the evidence. Not that I'd bet on it, but it's much harder to rule out than a lot of the stuff thrown around.

The only good argument I've ever heard against Berserkers is that, if they stop civilizations at some point in their advance, why don't they do it even earlier?

That is, why are we still here?

Not even necessary. Just the radio waves emanating from an earth-like planet would be /very/ detectable to us, over most of the galaxy, iirc.

Intergalactic travel may be impossibly hard. There is a gap of about a million light years that needs to be covered, and since you can't pick a spot to land on when you start your journey, you need either active guidance (which takes power) or an insane of dumb probes in order to end up someplace where you can start reproducing again.

I'm not going to say it's completely ruled out -- maybe you have something go completely dead in the intergalactic void that uses solar power from the new galaxy to wake up. But it could well be impossible.

"Mere" interstellar travel is not that tough when you have thousands of years. If it takes, say, 2 centuries to reach Bernard's Star, then another 4 centuries to build up civilization to the point where it can launch another interstellar craft, that's fast enough for a civilization at one end of the Milky Way to get all the way to the other end in 10 million years.

Maybe you can do interstellar travel by "island hopping" from our Oort cloud objects into a neighboring star's Oort cloud objects without ever having to do more than interplanetary travel in one go.

But I agree with your general point that slow-boat interstellar travel seems pretty straightforward.

"But I agree with your general point that slow-boat interstellar travel seems pretty straightforward."

Since the Voyager probe is already outside the solar system headed for another star, and it was launched 20 years after we first managed to get a satellite to orbit, It's obvious that unmanned travel is at this point trivial. Sadly, Voyager is not on a course to travel very close to another star.

However, manned interstellar travel is still non-trivial. And will probably remain so for the next 5 years.

It’s obvious that unmanned travel is at this point trivial

Nothing is obvious. Maybe Voyager will crash into a crystal sphere of dark matter.

> Maybe Voyager will crash into a crystal sphere of dark matter.

This is pretty much what has to happen to debunk interstellar travel and resolve the Fermi paradox in that way.

Even if there is no interstellar travel, Fermi's paradox is not resolved. We should be listening to radio emanation from aliens if they are anywhere near earth.

If civilizations cannot spread across stars, it doesn't become all that hard to imagine that there are plenty out there, but we just cannot see them because their signals get lost in the CMBR. There could be dozens out there, just none close enough for us to see.

How is this different from the Dream argument?

Or, for that matter, the Tommy Westphall Hypothesis:

If simulations or whole brain emulations were so easy we should have emulated C Elegans by now
We've had the connectome and enough computing power for decades/

The old arguments come around again; they always will.

Karl Smith is of an apocalyptic temperment, for instance. This is hardly new: Jesus and Paul both preached in this vein.

Now most of us shape our arguments to support our temperment, not the other way round. Karl doesn't want to talk about the Last Trumpet or the Son of Man. He finds other arguments. But he would certainly nod thoughtfully along with Paul as he writes, "the night is nearly over; the day is at hand."

What does it mean, really, to say "the universe" is "a simulation?" How does this differ from the position of Bishop Berkeley that the universe a thought in the mind of God? Well, you say "computers" and "aliens" where Berkeley said "mind" and "God." That's about it. As, today, persons so inclined are liable to encounter aliens where the visionaries of an earlier age conversed with angels.

The "simulation argument," I think, is mostly a way to have theism without God. It's not that I reject the argument. It's not the sort of thing that really can be rejected. But I think I see some of what motivates it: the hunger for a world that has a purpose, that makes sense, the need to believe that there IS a man behind the curtain who has all the answers and is ultimately in charge.

My temperment is to be dubious of such ideas. I don't carry much out of post-modern thought, but I do take this: an allergy to overarching meta-narratives. What could be more overarching than the alien computer that is simulating everything in our world?
Tyler Cohen

I don't have any idea why my comment ends with the words "Tyler Cohen," which isn't even the man's name. I wouldn't say no to an edit capabilty on these things.

The simulation hypothesis has nothing to do with longings for theism, any more than the Big Bang theory reflects wish fulfillment for a creation of the universe à la Genesis. Although if I recall, some astronomers clung to the "steady state" theory long past its sell-by date precisely because of their misguided suspicions along those lines.

Well, I rather think it does. I also think arguing _for_ the simulation hypothesis, as opposed to merely admitting it can't be refuted and saying, "Hey, who knows?" before passing the bong along, is a mark of derangement. I won't acknowledge it any better than a belief in CIA mind-control rays.

Are we sure that supernovae aren't being used as advertisements?

Without using your phone, can you tell me what the next QR code you see says?

It's still possible that the Crab Nebula is saying something like "Try Pan-Galactic Gargle Blaster!" without it being in a form we could comprehend yet. In any case, we aren't the target market. Just like we don't produce advertisements for wild animals on another continent, I wouldn't expect any such communication to have us in mind.

Nor does it seem that any animals are aware of all our communication occuring via the electromagnetic spectrum. But that certain'y doesn't mean we're not this technology And yet the possibility that electromagnetic waves turn out to be a relatively poor means of communication compared to some as-yet-undiscovered-by-humanity mechanism never seems to get much play in discussions of the Fermi Paradox.

Supernova aren't being used for advertisements in a way that is obvious to us but remember modern physics has enormously difficult time accounting for the way the universe looks on the largest scales (see galaxy rotation problem and the expansion of the universe). It may turn out that dark energy and dark matter are better explanations then the mere hand waving they appear to be, or we may develop a whole new understanding of gravity at some point. At the same time we might argue that the apparent discrepancy in the how rules of gravity operate on the scale of our solar system and smaller, and at galactic/visible universe scales might just be the result of the fact we're in a poorly designed simulation (see Ken Macleod's excellent The Restoration Game). However, to me it seems at least as plausible (relative to the simulation argument) that these issues with gravity could be the signature of intelligent life engaged in some serious cosmological engineering. I don't have a clever explanation as to why intelligent life would be engaged in cosmological engineering, and doing the same thing in every direction we look, but it's possible one day we'll look out at the stars and feel very silly there was ever a time after we started looking deep into space and couldn't see the signature of advanced intelligent life.

To the contrary, "they don't use the electromagnetic spectrum" is one of the standard explanations. It's just not a great explanation. It requires our understanding of physics be much more primitive than we think it is, and it requires any hypothetical aliens who actively want to communicate with us not being able to figure out that _we_ use radio.

> not being able to figure out that _we_ use radio.

Which is completely implausible, given how bright in radio spectrum things like early-warning radar and interplanetary mapping radar make us. They are considerably brighter than the sun and obviously artificial. They may have low information content, but they obviously advertise our presence and technology level at interstellar distances.

I would agree that we are clearly emitting signs of our existence in a measurable way across interstellar space. However, the next question becomes whether other entities care. Perhaps we aren't yet interesting enough, or enough of a resource or market to get above the hurdle rate of investing in us. We don't sell to undersea tube worms, nor do we farm them.

If we can't activate another species' fear or greed yet, we're more likely to be left alone.

Although now, that tells us that the investment in regular interstellar communication and travel must be so great that we don't have smaller organizations showing up to farm us or our solar system now.

Notably we have credible amateur attempts at interstellar communication by groups of humans _today_, so that also tells us something about the resources required. If interstellar societies can prevent this from happening, they have pretty tight control over their constituents.

You start getting into social explanations of the Fermi paradox when you go down this path, and I usually find them tough to swallow. They seem to require strong uniformity.

Yes, they have extremely low entropy, but not trivially periodic. They are obviously artificial.

"and it requires any hypothetical aliens who actively want to communicate with us not being able to figure out that _we_ use radio."

Or, a much more likely explanation, is that these very advanced aliens don't give a rats ass about some backward tribe stuck on 1 planet, anymore than the US would care to send smoke signals to jungle islands in the middle of the Pacific ocean. Is the lack of visible smoke signals or drum sounds evidence of no intelligent life beyond the island? Not really.

"anymore than the US would care to send smoke signals to jungle islands in the middle of the Pacific ocean"

But we did, in WWII (and before, with expeditions like Cook's and so on). It should be assumed that creatures technologically advanced enough to be able to contact intelligences located some distance away are curious enough to do so--regardless of the technology. In historical time, the distance between the ability to contact and the act of contacting isolated human communities has been a blink of an eye.

Really? Are you sure that the US individually visited every island? And that we managed to contact someone who would tell the rest of the tribe and be believed? Did we miss any? Any at all?

And keep in mind that there are far, far more stars in this galaxy than there are islands in the Pacific (or all of Earth for that matter).

And regardless, my point was that the US did not communicate in a fashion those natives would comprehend.

There are whole fields of people devoted to the study of those tribes. I was under the impression that the tribespeople can't walk around without tripping over an anthropologist.

Don't forget the "zoo hypothesis": perhaps we are being deliberately shielded from outside contact. In fact, there is one island on Earth whose inhabitants are deliberately isolated from the rest of the human race: North Sentinel Island. This is a policy of the Indian government, and the other governments of the world refrain from infringing.

The zoo hypothesis requires that no emergent intelligence ever disagree with that policy. Either that, or an extraordinarily effective, not-bothered-by-lightspeed-limits, totally invisible police to enforce it. It's vaguely plausible, because with sufficiently advanced technology one could imagine that, but it's a stretch.

Not at all. Other countries might theoretically disagree with India's "prime directive" policy on North Sentinel Island but refrain from violating it because India's sovereignty is recognized under international law.

It's easy to keep visitors out this way, keeping photons out might be a different story. But a sufficiently advanced civilization, with about a million years lead time from watching early hominids, might plausibly have constructed a different kind of "great filter" to keep us from seeing photons we're not supposed to see, using some as yet inconceivable technology.

They refrain from violating it because it would be technically difficult to circumvent India. There are a few isolated tribes, and you occasionally hear of violence done to them by criminals not well controlled by local governments.

In the case of interstellar travel, the technology required to defend against these incursions from a sophisticated foe must be truly magical. I don't rule it out, but I really doubt it.

Our sun is around 2 bilions of years younger than the median age of sunlike starts on the Milk Way. Also, all the evidence points that space travel is somewhat easy. Hell, for all we know, we could do interestelar travel now, it is just that lots of people would die in the way, it would be extremely expensive (but withing global GDP) and require the detonation of nuclear bombs for propulsion.

Fermi paradox is not based on communication. The point is that we shouldn't even be here, the entire galaxy should have been already colonized by aliens by the time we appeared.

Craig raises a good question. Would Tyler--or anyone else who agrees with his final lline--agree with this: "In any case, the Fermi paradox raises the likelihood that __God exists__." And if not, why not?

Quite right! Any argument that purports to be for the universe-as-simulation is only arguing for some kind of Creator. People who laugh themselves silly at arguments claiming to prove the existance of God have no problem with the idea of alien supercomputers. I can't see much to choose between them.

Well, at least with alien supercomputers one doesn't have to explain away the problem of evil....

One only has to explain evil away if one posits an omnipotent and _benevolent_ God, of course...

Does any religion posit otherwise?

All the polytheistic ones?

*Unless* benevolence equates to non-interference.

Does it?

The cleverest theists make this case all the time. To them, Jesus, Buddha, Mohammed, etc were purposeful tweaks of the simulation to see how we'd react.

How about the asteroid that killed off the dinosaurs, or the Black Plague, or the platypus?

If you were one of the alien simulators, wouldn't you want to insert stuff like that to see what happened?

If the mediocrity principle is true AND the many worlds interpretation of quantum mechanics is true AND it's possible to create strongly Godlike AI (i.e. with control over matter and energy) rather than just weakly Godlike AI (i.e. able to out-think humans but with limited control of matter and energy) THEN it's almost a certainty that some instances of the manifold are in fact God-Created universes including but not limited to ones in which the God of the universe is the same God as the one in the "book-of-the-God" and *yet* the "book-of-the-God" is inconsistent.

At the same time of course as the existence of universes with no Gods whatsoever which have just sprung into existence(!)

It is the exact same argument as the simulationist one.

Well, if the simulation was just the implanting of life on planet earth in this solar system, that would make a difference from the Dream argument cited by Rahul and that about God made by Berkeley cited by MikeP and Craig. The problem at that point would be the duration of the simulation/experiment... and this was exactly the problem of the protagonist of the comic tale I was citing in the previous post on Fermi's paradox. He was a scientist who engineered a machine able to find the exact date of any object with exact day precision. But at a certain point he started testing on objects he knew that should have been older then 1st July 1800 (or something like this) and he finds always that date as a kind of "limit" date for the past. Then many things happen and in the end he meets the aliens who disclose to him they were testing historical evolution on a twin earth millions of light years away from the original one in a smaller solar system so that 1 year on the original earth = 2 years on the fake one and the new earth was created on 1st July 1800 (or something like this). The experiment at that point was a failure because they didn't imagine the humans would have been discovering such a machine and they didn't calibrate the fake earth in order to prevent the scientist from discovering the truth...

>>Is the universe run by an alien version of Daniel Kahneman?

Or is he actually just an alien in disguise to start with?

....and if we were indeed rats in Kahneman's simulation what's wrong with jumping through hoops if he's rewarding us with cheese squares or whatever it is that they give rats? i.e. Even if we knew for sure we are in a simulation how should we change our responses?

We should attempt to learn all we can about the simulators, and to communicate with them if possible.

"Don't turn us off!" seems like an important message. They might not even know we exist.

Has communicating with the white-coat ever done a lab-rat much good? I'm skeptical.

What's the worst that can happen? Er, well, never mind.

So why does he charge for his books? To make the illusion seem more real?

The same reason the agents in "The Matrix" didn't offer Neo a few billion dollars to join their side.

But they did make the offer to Cypher...

what is the matter with people. the "fermi paradox", like most "paradoxes", is not a paradox. a paradox is a statement which, if translated into a logic that spits out truth values, breaks. that is it, really, I promise. people like to space out and "whoa man" like this is somehow deep and mysterious, but it's not. ever. it means your implicit set theory or logic isn't as completely specified as you [want to] think. ("this sentence is false" whooaaaaa mannnn.) humans have spent 4500 years masturbating over this.

if we take "paradox" to mean "counterintuitive to my way of thinking" I still say the fermi paradox fails. in fact, let me answer the "fermi paradox" AND the "are we living in a simulation?" questions simultaneously: there is nothing counterintuitive to the fact that ALIENS!!! seem not to be out and about. it turns out the universe is huge and things are really far apart! and traveling distances on that scale may well be physically impossible. "what about communication, though? light is fast!" sure is, but "huge" is really huge, and it takes light a long time to travel astronomical distances. furthermore, plenty of earth animals show no particular social inclination, nevermind gregarious social tendencies. on what basis are we assuming that ALIENS!!! are star-wars-style aliens (ie, humans, ie, higher apes, just, you know, even funnier looking)? maybe 90% of "habitable" (the "by star-wars-style furry humans with tusks" is silent) planets are packed with really smart snakes with sartorial style, an eye for color, and loads of rad inventions -- so rad they have in fact equipped them with interstellar electromagnetic cloaking devices so as not to even potentially be disturbed by gregarious higher apes from primitive lands. how would you know? and on what basis is your prior generated and how will you convince me it is anything but absurdly, comically poorly specified? our physical theories for basic laws we see and deal with every day (which we can't even say with confidence are universal or time-invariant) are still unable to account for the majority of mass/energy in the universe, which, by the way, we did just conclude is expanding, seemingly a detail a bright species would nail down well before it starts confidently throwing around probability distributions on its own likelihood at being alone in the universe.

oh, and yes. we are living in a simulation, and all of you are simulating idiots.

maybe effective deliberation over the likelihood of alien life/simulation/authoritarian sky daddies is sadly beyond a species still scratching its collective head over the form, function, and maintenance of a medium of exchange. (question: what are "precious metals" like on earth-2, and how do they track M4?)

1 - Interestelar travel is viable for a sificiently advanced species.
2 - There is nothing special with Earth, so there are inteligent species born in lots of other planets, and evolve at the same speed we did here on Earth.
3 - Our star is very young by the galatic parameters.

Consequently, there are advanced species spreaded through the entire galaxy. Join that with:
4 - Natural evolution implies that most species won't stop reproducing unless there is some resource limit.

And, as a consequence, there are advanced species literaly through the entire galaxy. That means, there isn't a single place in galaxy without them. Now add:
5 - There aren't any aliens here.
And you get a paradox. That's Fermi's paradox.

so, that part where I pointed out you have no basis to posit a gregarious and social species inclined to exploration (and thus space travel)? that part where I kept pointing out "intelligent" and "advanced" does not equate with "higher ape like" by any logic with which I'm familiar, and seems absurdly arrogant to assume away, at least to this particular higher ape? did you miss all of that?

take my example of planets full of really, really intelligent, brilliant snakes, disinclined to interstellar travel, preferring instead to ponder the mysteries of the universe in undisturbed solitude, alone with their cloaked inventions. that's possible, right? yeah? then it's not a "paradox".

The possibility of imagining a species that doesn't expand or communicate, implausible on its own, doesn't solve the general problem. Why are _all_ species like that? You only need one that isn't, and they should be all over the place, including here, by now.

wait, why is that implausible? because you're not like that, thus it seems peculiar to you, thus it doesn't fit the just-so simplifying narrative you apply to your own evolutionary adaptation, thus it's not possible, thus paradox, QED? show me the train of logic that leads to your baking in these higher-ape-like axioms, or for that matter these earthlike-planet axioms.

and why do I need "all over the place"? do we understand the emergence of life better than I realized? I thought we were still telling "sure, why not, that probably works" level stories, but I'd love to read the account that gives me conditions that, say, we could reproduce via experiment on earth-2, given the opportunity and time. can't intelligent and advanced life be elsewhere but rare?

you don't like my snakes planet. take another, then: is it not possible that the more intelligent and advanced of the creatures would have faced evolutionary pressure to, in fact, _hide_? maybe they even have a religion. maybe they are dwarves, living in mountains, performing metallurgical miracles, and supernatural beliefs as to the nature of what is "out there" on the surface of the planet persist, owing perhaps to the race of movie-dinosaurs of raptor-in-window variety not having been fortuitously wiped out by an extinction event, yet the friendly, mountain-dwelling dwarves, through guile and cunning, managed to evolve in parallel, though in constant danger before retreating to mountain safety? is that not possible?

how many stories do I have to tell?

or is what's really going on here that you've so constrained the probability space of your problem that you've assumed away all counterarguments?

I have no doubt you can invent stories that appear to explain intelligent species that choose to neither expand nor communicate. I find those stories implausible because a species must necessarily be an expander to even exist, otherwise it would be out-competed. I am less convinced by the communication side of things - in fact, it seems pretty smart to stay quiet if you don't know what's out there.

But this is all besides the point. It's not a problem that there could be some weird intelligent species that has managed to turn off evolution. The problem is, why have _all_ intelligent species done it? It makes you think, something is wrong with the assumptions that inclined you to think there were a lot of intelligent species in the first place.

it seems to me like "you" (for all values of "you" inclined to engage in fermi problem pontification) are in effect saying, "yeah, yeah, so there are things we don't understand very well if at all, and we are making massive generalizations about the fundamental nature of a potentially wholly contingent, emergent process which develops through environmental adaptation, and yeah maybe there are unfathomably many environments we've never experienced or thought very hard about in the first place, and yeah maybe our imaginations and biases are artificially constraining our probability space -- but let me assert a fully-justified prior anyway and plug it into bayes theorem and PARADOX!" these arguments seem more hand-wavy and nonsensical to me than positive arguments for the existence of god, and I'm not a theist.


You're not responding to Finch's point. Why is it plausible that, after 12 billion years, NO intelligent species with the desire and means for interstellar travel has emerged in our galaxy?

Also, you need to learn to use upper case characters.


Given that we are still, at present, uncertain as to the facts of the matter with respect to questions such as, "Was there ever bacterial life on the planet Mars? How much liquid water flowed on its surface, and for how long, and what happened?" Not to mention more, shall we say, parochial questions of climate change and projections of future weather circumstances, I bask in continual awe at the certainty with which people are happy to assert that if there were advanced civilizations elsewhere in our galaxy -- our galaxy of 200-400 billion stars, according to the source of all knowledge, and over a hundred thousand light years in diameter -- that had undertaken space flight of any kind, we would know about it.

How, pray tell? Show your work. After you tell me, you may want to inform these astronomers, who as of about a week ago sound like they are unaware of your certain evidence, to say the least:

Furthermore, we are an "advanced intelligence", or like to think so anyway, and I hope that you will agree with me that we have done dramatically less space travel than our maximum technological bound, and by any measure will continue to do so, as our explorations are constrained by domestic political economy concerns (governments shy from manned space travel because it is expensive, of questionable immediate economic benefit to put it mildly, and very dangerous in a way citizens find demoralizing when shuttles explode and kill smiling schoolteachers on national television, and private corporations and citizens are highly restricted by regulatory demands for any number of reasons including the previously mentioned plus no doubt issues such as national security concerns) -- am I asserting that an alien intelligence has "stopped evolution", as was previously asserted by another commenter replying to me, to suggest that maybe just maybe even if there are great-ape-like intelligences out there at a similar or more advanced level of technological intelligence as ours, they may be similarly constrained, or -- gasp! -- maybe even just a little tiny bit moreso such that no space travel had occurred? Is that too completely outside the bounds of reason?

No one is suggesting, let alone expressing "certainty," that we could detect "space flight of any kind." The point, which you keep missing, is that the galaxy is so old and has so many stars that if interstellar exploration/colonization is possible at all, we would expect to see some signs of it. Even at a very slow expansion rate, it would only take on the order millions of years to expand from a single solar system to every star in the galaxy. And yet the galaxy is billions of years old. And has hundreds of billions of stars. But there's still no sign of any aliens.

The point that you keep missing is that I'm arguing that you have absolutely no justification *whatsoever* for asserting so confidently that we would "see the signs". 200-400 billion stars -- note our bound on the number of stars is plus or minus a hundred billion -- and you are saying because there are that many and everything is old that if interstellar space flight were possible we would expect to see the signs. I am pointing out that we have a planet called Mars that we know has frozen water and just recently have concluded with reasonable confidence had surface liquid water in comparable quantities to Earth today, but we have no idea if there was bacterial life, or more developed life, or if there are traces remaining in dried-up riverbeds, or whatever. We simply don't know, and it's a planet right there in our backyard. Note the invalid assertion "The planet has been right there for a long time, we've known about it longer than we've even had the concept of 'galaxies', if life on Mars were possible in any form we would have seen the signs by now."

You think you understand "interstellar space flight and colonization" and all detection thereof on a galactic scale sufficiently well to make assertions about what is or is not possible or out there or even in fact LIKELY to be possible or out there based on what we have seen using the tools we have. I'm saying that you don't come close, nor do the bored graduate students who write down a cellular automaton to "show" how interstellar colonization could work. Your response to that is to assert once again with feeling what you think you know, as if I just totally missed it the first time. I'm not the one missing the point.

200-400 billion stars — note our bound on the number of stars is plus or minus a hundred billion — and you are saying because there are that many and everything is old that if interstellar space flight were possible we would expect to see the signs.

That's right. And you have offered no counterargument. I have no idea why you think the example of Mars somehow undermines this expectation. Mars is one planet in one star system. The galaxy has hundreds of billions of stars, and probably at least as many planets.

Also, we know Mars is not operating starships with about as much confidence as we know America is not operating starships.

In fact, probably slightly better confidence, as we can detect the remnants of industrial civilization in America.

here's what i find so funny about this. i think choncan's points are irrefutable, but obviously others disagree. still, how can fermi's "proof" (it's not a paradox) survive if you can pick holes in the assumptions so easily? we're like fleas assuming to know what goes on in the minds of seahorses or humans. everything the fermi "paradox" assumes is completely baseless. it's a very appealing just so story, but people who think they're thinking rationally should realize there's no reason to make any of the critical assumptions. e.g., a better answer than we're in a simulation is that no one ever leaves home, because once you're sufficiently advanced, you stay on your own planet and live in a simulation (if you can live forever, or close enough, last thing you would do is risk your real body on a journey cross the universe). it's also funny that people assume it's so obvious we can detect the presence of advanced aliens of any sort, or that we can conceive of why they may want to hide, or even wall us off from any evidence of advanced simulations. but please, just ignore these points and assume, as you did with choncan, that i just don't get the point about radio reaching here from elsewhere, etc.

i think choncan’s points are irrefutable

What irrefutable points would those be, choncan? Sorry, I mean superflat. I see none in your -- I mean, choncan's -- rambling and unfocused comments. Please list these "irrefutable points" clearly and concisely.

Wasn't me, Major. (Email our fearless co-bloggers and ask, if you like.) Though I'm beaming with parental pride to see my early capitalization fashion trend catching on.

(...and for the record, my arguments are far from irrefutable. They have not, however, been refuted by you or anyone else, despite my repeated requests that you show your work and back up your sweeping claims. I do apologize for my "rambling and unfocused" commentary, those of us too mentally feeble to make galaxy-wide astronomical discoveries through the process of pure reason have to work within our natural limits. Thank you for your understanding.)

> and for the record, my arguments are far from irrefutable.

Yes, and if I understand them correctly (and I have to admit I'm really struggling here), they come down to:
(1) Intelligent life is really common
(2) Every single example of it ever has a just-so story that explains why it acts differently from every other product of evolution we've ever seen.

Therefore reasoning about the Fermi paradox is useless, and it's not even a paradox.

Wasn’t me, Major.

Suuuuure. It just so happens that "superflat" has the same lower-case quirk as you do and writes in the same rambling style. You know, if you're so insecure about your claims that you feel the need to bolster them with effusive praise under false names ("choncan’s points are irrefutable"), maybe you should take that as a sign that you need to rethink your position.

Finch, +1

@choncan: if you think you have a simple answer to a question which had someone lilke Enrico Fermi puzzled, the default assumption should be that you don't understand it as well as he did.

know who wouldn't have liked that sort of blind appeal to authority? enrico fermi. if you're engaged in a rhetorical style that would've displeased fermi, perhaps you should reconsider your rhetorical style.

note also that I am not making a yea or nay argument, I am making an intellectual modesty argument. I am not presenting a "simple answer" to the question, I am saying the question is poorly specified and the assumed conclusion -- which, by the way, is what I'm attacking -- results from a laundry list of unexamined assumptions.

You're appealing to authority on your rhetorical style. Know who wouldn't have liked that? Fermi.

Wait, I think we have an infinite loop here.

What's with the aversion to capitalization? A subtle point about overthrow of authority?

I am a simulation sent from the future, where we from the land of the repugnant conclusion made flesh live, if it be life, so far below sustenance wages that we can't afford shift keys.

Then what's with the retained capital "I"'s? Hubris?

The Fermi paradox is easily countered by the weak anthropic principle: no matter how unlikely we are, we have to be here to ask how likely intelligent life is. Given an infinite universe, its existence in a given light-cone could be one in a trillion or less.

It's hard to say how unlikely the rise of intelligent, tool-using, trading life is, but it took 1.8B years just to get multicellular life -- humans have been around for an eyeblink by comparison. And even humans as we know them are a very recent phenomenon that emerged through a pretty small genetic bottleneck from ancestors that used nothing but hand-axes as tools for perhaps a million years. And even high-tech humans inhabit a very small timespan of modern human existence.

As we explore more exoplanets, the uniqueness of intelligent life will become better understood.

It is not countered by the weak anthropic principle because you sun is young. If we appeared on one of the first stars with metalic planetary nebulae out there, we could claim that, but we didn't.

That doesn't really tell us much, though. If intelligent life is so unlikely it only appears in 1e+100 light cones at any point between Big Bang and heat death, the age might be largely irrelevant to our observations.

the anthropic principle is not a valid argument. Its perfectly circular.
It boils down to:
"Why is X the way it is, well because it just so happens that it is, now shut up and stop asking questions that make us feel uncomfortable."

The WAP is completely valid, and not at all circular. It simply says that in order for intelligent life to exist, the conditions for intelligent life to arise had to observed locally.

If anything, it's so obviously true it can labelled a truism.

A couple other questions:

Why are humans the first major tool-using, trading life form on this planet? Why wasn't there a genius dinosaur? Or some form of genius aquatic life? What's different about us, now, compared to other times and places, just on Earth?

Can you be absolutely sure there was no "genius dinosaur"?

Today, we have several tool-using and tool-making species: not just primates, but various birds and aquatic life. There is no reason to believe this is not typical, i.e. at any given time in the last few hundred million years of biological history there were probably at least half a dozen toolmaking animals at any given time. Perhaps one or two took it a step further? And even some ant species today practice a primitive form of agriculture, which is the crucial enabling technology for anything resembling a civilization.

Suppose, for the sake of argument, that some dinosaur species a hundred million years ago had reached, say, a Mayan level of civilization and flourished for a few centuries or millennia before vanishing. It's entirely likely that erosion and tectonic activity would leave no trace of them at all. Indeed, a supertropical hothouse climate would leave few obvious traces even after only a thousand years, like the Mayan pyramids buried in tropical jungles.

There's absolutely no evidence for any of this, of course. However I'm just pointing out that we can't with certainty assign the value of 1 to the datapoint about the number of intelligent species that have arisen on Earth, although ours is very probably the first industrial civilization.

I think we would have found evidence of their cities. Stones tend to last, and so does metal.

Not if they're twenty miles below the ocean floor, after a hundred million years of shifting tectonic plates.

And if they stayed on the surface they wouldn't last either: the Grand Canyon was carved in a mere 17 million years or so. You're claiming that some stone pyramid from the Jurassic would still be standing?

No, we would have found them, for the same reason we find dinosaur bones.

There may have been genius aquatic life: today, cetaceans and octopuses are pretty smart, and there is no reason to believe our era is atypical in this regard. Very large brains are easier to manage when you're floating.

The problem is that a watery environment pretty much precludes a technological civilization. First of all the imperative evolutionary demands of streamlined swimming tend to whittle away any limbs that could be used for proper grasping and manipulation (although octopuses are an interesting counterpoint, any kind of manual labor or hammering, etc is arduous or involves infeasible energy expenditure in viscous water). And technological artifacts don't last, or can't be created in the first place: water dissolves, salt water corrodes, biochemical processes decompose, no fire or properly controlled chemistry, etc.

Life on earth very likely could only have arisen in a liquid environment, which promotes a promiscuous dance of chemicals, but for the reasons mentioned above a technological civilization could only have arisen on land. Perhaps there's a lesson here: in order to advance to the next level, sometimes life needs to leave one environment and move into another. Perhaps that's the answer to the Fermi paradox: the aliens went down a rabbit hole into virtual cyberspace, or down a black hole into a different universe of their own creation, one with physical constants inimical for life to arise but much more suitable for already-existing life to flourish.

We were /not/ the first major tool using, trading life form on this planet.

It amazes me that the Fermi paradox is even considered interesting given the vast spatial-temporal space in which we exist. Let's remove the spatial component and just focus on the temporal. Given human civilization is approximately 10,000 years old and the age of the Earth is 4.54 billion years, civilized humans have only inhabited the planet for 0.0002 % of its existence. Given that our capacity to observe extraterrestrial intelligence is, rounding up, 100 years old, that means we have only been looking for 0.000002 % of the existence of the Earth. Given that the age of the universe is 13.75 billion years, we've only been civilized for 0.00007 % of the existence of the universe. We've only been looking for life for 0.0000007 % of the existence of the universe. If you assume that intelligence on other planets arise in relatively the same amount of time as here, the chances of temporal overlap alone are slim.

Let's further remove the spatial component by hypothesizing that we are not the first intelligent civilization to arise on Earth. There has been sufficient time on this planet for more than 1 intelligent civilization to arise and decline. How long would evidence of that civilization be identifiable?

The paradox for me is why people think we have much of a chance of encountering an extraterrestrial intelligence. Maybe the reason the Fermi paradox persists is attributable to the reputation of its originator.

We also see no evidence that anyone has been through here before.

We’ve only been looking for life for 0.0000007 % of the existence of the universe. If you assume that intelligence on other planets arise in relatively the same amount of time as here, the chances of temporal overlap alone are slim.

I don't know why you think "the chances of temporal overlap alone are slim." Your unstated assumption seems to be that intelligent species survive for only a short time and then become extinct. But why is that plausible? Even if the assumption is true in almost all cases, even if, say, only one in a thousand intelligent species survives long enough to develop interstellar spaceflight, we'd still expect the galaxy to be colonized by now, given how old it is.

Great points. This is why I say the weak anthropic principle is so much more powerful than the Fermi paradox.

We're so delightfully arrogant. If we haven't found something 5 seconds after we start looking it must not exist, and nothing is real to boot. Compared to what we spend on wars and television we aren't really even trying to look.

No one said "it must not exist." If it does exist, why don't we see any signs of it? Even if intelligence and civilization arises in only one star system in a million, then as Marcos said the galaxy should have been colonized before humans even evolved.

This is what I mean by arrogant. Signs of what? Signs of what we would do if someone just like us happened to be directly in the neighborhood? Anthropomorphism (of aliens!) is the height of arrogance. What have we done to detect an alien civilization - we haven't even landed a person on the planet closest to us. If an alien civilization lived on an a planet 250 light years away from us, broadcasting their hearts away, we still wouldn't know.

The idea that life is rare or unique to earth is the ultimate religion. That the universe formed to fit us, rather than the other way around.

In fact, the whole reason it's called a paradox is that most smart people strongly believed that it _should_ exist.

The surprising thing is that there seems to be a ton of evidence that we are alone. We've found none of the evidence you would expect to see if even _one_ extraterrestrial intelligence, that behaved in the way evolution has made all living things we know of behave, existed.

So either extraterrestrial intelligent life is really, really rare, or something very strange is going on. These are interesting conclusions, and they prompt interesting questions. And that's why the Fermi Paradox is such a useful tool for focusing our thinking.

In any case, the Fermi paradox raises the likelihood that we are living in a simulation. - more specifically, the abundance of planets and the lack of subsequent aliens raises that likelihood.

But in any case, yes. And why would this simulation happen? Lots of reasons:
1) Humanity could have been the first species to develop in the galaxy, and could have fought a lot of wars with aliens, and someone could come up with a 9th-grade science fair project: 'what would the universe be like if humans had never had to fight an interstellar war'.
2) Another species could have wiped us out, and created a simulation of us as an archive.
3) Humans of 2045 or 2100 or somesuch (with or without aliens yet encountered) could be simulating the relatively recent past
4) We're the 'victims' in a 'sim-entertainment' - an underdeveloped world is attacked by aliens, black hole, asteroid, etc.
5) We're the citizens of a very advanced copy of 'SimEarth'.
6) We're a random civilization built in some very advanced copy of 'Spore'
7) Someone set up a galactic simulation game with a bunch of civilizations that all start at the exact same time, to see which one eventually conquers the galaxy.

and plenty more

We're a side effect in a simulation of the effects of unit charge being 0.000000017% higher.

There's little reason to believe the simulations are centered on us.

"In any case, the Fermi paradox raises the likelihood that we are living in a simulation."

I think this is a stretch unless we have any compelling reasons to believe an alien civilization simulating a universe would have a preference one way or another about whether to include more than one intelligent civilization, how far apart to space them, etc. Also, given Moore's Law stuff (which, yes, may run up against limits, but eventually there are likely to be breakthroughs in quantum computing etc.), it seems likely that if a civilization can simulate a universe in year t=0, by t=5 or 10 or 20 they will be able to simulate many universes. If each of them has different numbers of intelligent civilizations, that casts further confusion on the question.

I think that if we are going to make impossible arguments about whether or not we are living in a simulation, quantum mechanics might provide better hints. I am not one of the five people in the world (or whatever) who understand the subject, but there seems to be some small level of similarity between how observations of the universe at the finest levels work (that is, it's all just foamy/wavy probability until you make an observation and things collapse into some level of certainty) and how video game designers save on horsepower by only rendering the visible scene.

(Someone who is smarter than I am should tell me whether this notion makes any sense, or whether I am committing the very popular pseudoscientific trend of greatly over-extrapolating QM and jamming it into areas where it doesn't really fit.)

The latter. But you're not handwaving as vigorously as the person who got a flock of sheep, painted one word on each sheep, took pictures through the day as the flock grazed, and called the result "quantum poetry."

The simulation idea strikes me as completely ridiculous, but at this post I collect a few links to a couple of these type of theories;

If we're in a simulation, there probably is no "we," just me. The rest of you lots are just part of the program.

If you're willing to allow solipsist concepts, then it's far more likely that you (I) are actually living in a series of Boltzman Brains than in a simulation based on a full-sized universe...

They all transitioned into a demographic "black hole" and remained economically stagnant before they could achieve interstellar flight.

Before they achieved radio communication you mean.

...and simulations.

Two things worth pointing out. First, against certainty about the non-existence of von Neumann probes: we've barely scratched the surface of solar system exploration, so it's a little early to say they're not here. There may be very good reasons that you wouldn't find such things on planets, which have gravity fields that are expensive to get back out of, which is what any effective von Neumann probe will need to do to keep spreading. What about the asteroid belt and comets? Second, regarding the Great Silence, assume a twin Earth were orbiting Alpha Centauri right now, giving off the same amount of signals. Can we be sure we would know about it? As our technology develops, the chance that we would hear ourselves would go up; although there are arguments that right now we couldn't hear ourselves from even a light year away. We might have greater certainty that there is in fact a Great Silence if we used some index like "how close would we have to be to a Twin Earth to detect it". Right now, that index would say "pretty close".

It's at least 50 light years, since that's roughly the time since we've turned on big radars.

It's probably more than that if the detecting civilization is only slightly more advanced than ours. They'll see our atmospheric constituents.

I sometimes wonder if the placebo effect is evidence for living in a simulation. Maybe the simulation software uses heuristics and takes shortcuts instead of going to the trouble of computing the actual effect of a drug on your body (which, after all, contains more cells than there are stars in the Milky Way Galaxy, not to mention an order of magnitude more cells in your corporal ecosystem which aren't you, i.e. bacteria and such).

Maybe relativity is another simulator design decision. It sure is convenient not to have to deal with absolute frames of reference.

Also: it's worth trying to more rigorously define what "simulation" means. We don't want to include rose-colored glasses as a simulation, nor do we want to include a direct input from base reality to our brains that gets manipulated and bound together to create our experience. Even if your reality begins with digital inputs from a computer to your brain, and not light or pressure or pressure waves incident on electrochemical transducers (your senses), you're still constructing reality out of inputs - that is, there is still a thing that you experience as a cup of coffee, whether or not at some level it's just a computer telling you that it's there. The key seems to be that someone or something is *intentionally* doing this, and keeping us from getting information about what else is in the universe that the simulation-running computer is in. It's this component of the simulation argument, that there's something with the intention to keep us in the dark with incomplete knowledge of the universe in which we're a simulation, that's most interesting about this environment. Think about it for a second - if there's no simulatOR, all we're saying is that we have incomplete knowledge of the universe, which I think we already knew.

To me the Fermi Paradox is as simple as the odds of tool-using, socially adaptive, meta-tribe life evolving. For hundreds of millions of years neither ocean life, nor dinosaurs, nor early mammals evolved anything like homo sapiens. Not even stone spearheads were developed, and stone lasts long enough that we would have found them by now. Tool use isn't enough - the social skills have to be adapted to a global society, to support sufficient specialization of labor and to avoid eternal tribal conflict.

Even home sapiens had fire and stone tools for a very long time in some sort of hunter-gatherer equilibrium state, not much more advanced that a troop of chimpanzees or pod of dolphins.

Then, BAM!, we take over the whole world and fly into space in a blink of an eye (geologically).

This tells me that once intelligence and social skills reach a tipping point, space faring happens pretty fast. BUT, evolving that intelligence and social skill necessary to build a bigger-than-Dunbar's-number society is by no means guaranteed. In fact, it probably only happens under certain conditions - and something about the dinosaur era made those conditions impossible/implausible. Otherwise we would have some artifacts of the dinosaur's spacefaring and nuclear power industries.

There are 7 billion humans playing Universe because Chuck Norris allows them to live.

The Fermi paradox is linked with the Doomsday argument. If there are many long lived (millions of year plus) technological space travelling civilizations, spread across the universe, then any random observer would most likely be born into such a civilization. Instead we find ourselves in a civilization barely out of the stone age, and prior to any space travel - which if the Fermi model of the universe is correct- must be incredibly rare.

My view, and I would love to be proved wrong because it is a profoundly depressing conclusion, is that technological civilizations will always achieve AI prior to undertaking of being capable of interstellar travel. In the one case we know of (ours) that certainly appears true, Moore's law is progressing much faster than our space craft design. More generally you would expect this to be true - it's hard to imagine spacecraft building without computers, but we can easily imagine a world with computers but no space craft. The simulation argument is also consistent with this. To create a simulation of the universe takes very sophisticated computing power, and of course any entity that could create such a powerful computer would easily have been able manage Artificial Intelligence and uploading of their "intellect".

In my view therefore we should focus on the game theory of super-intelligent self programming entities. One thing that will immediately be clear to them is that the universe can contain more than more of them. They will also conclude that these other entities could be hostile to them. The correct course of action is therefore to program yourself to be super paranoid if you want to survive. Any entity that did not want to survive of course, or had ethical concerns, would either modify it's programming so that it did want to survive or didn't have ethical concerns. If it didn't do so, very quickly it would be attacked and destroyed by other super-intelligent beings very quickly. Given this, the very first entity to achieve AI on any world will be quickly trying to get to the stage where it can destroy all the other entities.

This solves the doomsday paradox - civilizations such as ours have billions of observers, but very quickly they converge on one superintelligent observer, which is also long lasting. So the chances are you will be born into a pre-Ai society with many short lived individuals, since that is where the majority of observers in the universe exist.

What about the Fermi paradox - well these superintelligent superparanoid AIs will take great care to be invisible to any observer, especially one as underdeveloped as ourselves. They remain paranoid even after destroying everyone else on their world as they are aware that many other planets could also have an AI as well, and they may well be stronger than themselves. Space is big, and probably they can hide for millions or billions of years. A new species close to developing AI in their immediate neighborhood therefore presents a problem to them. If they destroy us, they will call attention to themselves, perhaps leading to their destruction. Possibly they will wait until we develop an AI then try subtly to destroy that, perhaps by some advanced version of a computer virus. Or they will arrange a natural disaster that appears natural, just before we develop the first AI. Either way the future looks pretty bleak for the human race, especially given we are probably only decades away from the first AI. As I say a bleak scenario, and I hope someone can prove me wrong.

Why wouldn't the first AI have taken over everything and prevented competitors from emerging?

Why should malevolent AIs wait for us to get reasonably strong before destroying us? Why not strangle in the crib?

Why would a super intelligent AI care about survival? Maybe it would find that meeting a another AI that was stronger and being destroyed was interesting. Why would it feel compelled to compete? To find a more attractive mate?

If it didn't, it would be overtaken by those that did. You need to posit incredible uniformity to believe the universe is teaming with smart beings and machines, but none of them, not one, not ever, was a survivor who tried to grow more of his kind like literally every other living thing we've actually seen.

It's an extraordinary explanation. Everything else in the universe is completely different from all life as we know it, in a very specific way. Do you understand why people find it implausible?

No, what I don't understand why you think that non living intelligences would be similar to living intelligences

Finch and Robbi, it's simple evolution, the surviving AIs will be the ones who care deeply about surviving, an initial population may contain all sorts of diversity in wants, but the final population will be full of paranoid entities whose initial choice was to survive at all costs.

One answer to why the first AI did not just prevent other competitors emerging is that the potential competitors maybe were not in it's light cone when it was first emerging. I have often wondered if an AI can stay coherent across light years, the risk of spreading your consciousness across light years, worrying for a paranoid entity, is that part of you will detach itself and you end up fighting yourself. So it the AI will likely be compact and would therefore have to travel to intervene, which is costly and risky, making it even more likely that the galaxy and universe contain multiple AIs.

On why we haven't yet been squashed, any AI knows that potentially there are other AIs lurking out there that it cannot see, potentially more powerful than it, potentially with the capability to detect even subtle changes in our biosphere by an AI. There is therefore significant risk of detection if an AI squashes us (when you have a potential lifespan of billions of year even a very small repeated risk is significant). The best bet for any AI is to therefore to hope we will destroy ourselves before reaching AI, which to be fair we have looked like doing on several occasions. It may also be easier to destruct an AI than a world or maybe we are the equivalent of a canary in an AI's backyard. If we get destroyed the AI knows that there is a competitor about.

I think this is the "everyone is hiding from the berserkers" theory. It's not a bad one.

i think the impact of the technological development divide you ID -- between computing and space travel -- more likely leads to a different result -- why leave the home, and risk a body that can likely live a very long time if kept in the basement, when you can "explore" the world either remotely, or in a sim? put another way, why assume the real world is more interesting than sims to a very advanced civilization? the answer may just be very few aliens leave home, because there's little reason to do so (seriously, are any of the commenters about to sign up for a 20 year trip to a star/planet you may not reach, that's unlikely to have anything of real interest, with no real benefit (reputation/monetary/otherwise) to make such a trip worthwhile?).

i think the impact of the technological development divide you ID — between computing and space travel — more likely leads to a different result — why leave the home, and risk a body that can likely live a very long time if kept in the basement, when you can “explore” the world either remotely, or in a sim? put another way, why assume the real world is more interesting than sims to a very advanced civilization? the answer may just be very few aliens leave home, because there’s little reason to do so

Because there's a much greater risk that a civilzation will be destroyed if it stays in one place than if it spreads out across the galaxy. Again, why is it plausible that EVERY civilization would choose to stay home?

it doesn't have to be every civilization. why are you assuming that even if some civs don't stay home, they nonetheless come here, and reveal themselves, or that they came here within the window when we would have noticed (maybe aliens have come every 10,000 years, didn't think much of us last time round, or come frequently, every 1000 years or so, but nothing worth their attention)? why are you assuming that they send signals we can detect in the short time we've been listening)? the conditions for aliens to have been detected by us seem very, very narrow, no matter how many aliens there are, or what their capabilities. any my just so story makes as much sense as fermi's (which is based on accepting certain assumptions that drive his result, which is an easy game to play). also, very, very smart people frequently come to very, very dumb conclusions. so the fact that it was -- gasp -- fermi doesn't really impress me much. (pick everyone who's got an IQ over 180 or whatever, and they obviously don't agree on everything, or even much -- see all the squabbles between the econ bloggers -- so clearly very very smart people are frequently wrong.)

Superflat - I would like to believe that AI and uploading leads to a nice peaceful community of people just interested in exploring some internal world, but unfortunately we know from our own experiences that there are dangerous people around. Once you are software you can rapidly improve your intellect and become more dangerous, potentially over a very short period of time. The first AIs on any world will know that if they settle down to computer games, eventually a bad person will be uploaded who will try to use this power to become more dangerous to them and their potential billion year life span. You then face a choice, carry on playing games or also upgrade your abilities, and the arms race is on. To coin a phrase, only the paranoid survive. And being paranoid you don't spend time on computer games, you spend the time on upgrading your capabilities.

It is very sad, but this stage we are in is probably as good as it ever gets (in the whole universe) for biological intelligence such as ours, we have enough technology so our lives are pleasant but we don't have AI yet. Enjoy it while you can and hope Tyler is right about a technological slowdown!

it doesn’t have to be every civilization.

It would only take one to spread across the entire galaxy in a few million years, even at a very slow rate of expansion. And in a galaxy of hundreds of billions of stars, it's not likely to be just one. That's what makes your "maybe they all stayed home" and "maybe they're all hiding" speculations so wildly implausible.

I have thought that this idea (inward focus, computer simulated reality) was almost self evidentially true as the explanation for the Fermi paradox. We(humans) are enamored at the Universe at the moment. We should be. We have only recently developed the tools necessary to see the breadth and depth of the Universe we inhabit, it is all still new and wondrous. Simulation technology is still in its infancy. When simulation technology is as good as reality and ultimately ‘better’ than reality, then we will understand the Fermi paradox is not a paradox at all. All of the aspects of our limited experience as flesh and blood humans simply will not be able to compete with what is possible in a simulation with technology 1000 years more advanced than what we have now. The real world will be almost infinitely less inspiring and interesting than what the simulation world will be to its inhabitants. There is another argument to explain the Fermi paradox involving AGI’s and whether they ultimately gain control or we become them, but the end result still is the grans simulation and inward exploration not outward.

The next question is equally important. Does a ‘morality’ or imperative evolve in these simulation civilizations to assist other fledgling sentient organisms in other star systems or do they evolve a “live and let live” morality and only interfere in the real world as they see a need for preventive self-protection. A strong argument can be made that there will be great variation in the initial evolved moralities of biological organisms. Another strong argument can be made that certain moralities have better long-term survival odds and therefore civilizations that survive long-term will have similar moralities. A sufficiently advanced civilization could send investigative probes to all the stars in a galaxy over a relatively short period of time. There are probably many reasons for a civilization to do this, but only one is needed. The one reason all advanced civilizations have in common is self-preservation. To have the ability and the desire and yet not to do it seems illogical. The odds are low that we are the first advanced technological civilization to evolve in our galaxy. I therefore think it is highly likely that our solar system has been observed and might currently be observed. There is another possibility though. If extremely advanced simulations are as likely as I believe them to be, then the chance that we are in a simulation now is fairly high. Why wouldn’t the first advanced civilization to probe the galaxy not find all of the exceptional planets that have life evolving on them and record them and then simulate them, similar to the way we go on vacation and take pictures or movies. Surely they would have the technology to record at the level necessary to accomplish this. As someone said earlier, the univers is BIG. Why take that multi-lightyear trip when you can simulate the real thing with complete fidelity.

1. Evolution does not necessarily favor technology, e.g. dinosaurs. It took a planetary cataclysm to rid the planet of its dominant life form so that we, the teleological inheritors of 'technology' could come into existence over the next 65 million years, only producing Fermi and his paradox one millionth of that time ago. Even if our planet is typical, the evolutionary course of the human genome might be special, and even given that, our preference for developing tools, civilization and/or large cerebral cortex, (only 10,000 to 1m years old, depending on your criteria) could be special.

2. If our planet is typical, then we should assume that the vast majority of planets get smacked with a large meteor every 60-200ish million years. Perhaps this is not generally enough time to get from the prokaryote-eukaryote barrier to interstellar travel before the great extinction/nuclear war/whatever.

I think the answer to whether being in a sim favors the fermi paradox depends on how much computational resource we have and whether the medicrity principle is true.

If we have limited computational resource THEN it's likely that we would exclude an equivalently (or greater) technologically advanced alien civilization if we were expending a significant proportion of our computational resource on simulating the Earth.

If we have unlimited computational resource THEN it's easy enough to simulate aliens as well as ourselves.

What about the mediocrity principle? If it is true then we just need to ask how many alien simulations we currently have:
Well what percentage of our present simulations contain aliens? Few of them compared to human simulations.
So we'd expect ceterus paribus that in all cases we'd have less alien simulations than human ones.

In the end I'd have to argue that your hypothesis is likely false for the above reasons.

I'm glad others are pondering these same questions.

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