A New Take On the Fermi Paradox

TravisTR points out some new research that aims to update and supplement the Fermi paradox — the idea that if intelligent life was as common as we expect, we should have detected it by now. The academic paper (PDF) from scientists at the National Technical University of Ukraine is based on the idea that civilizations can't expand forever on their own. The authors make the assumption that an isolated civilization will eventually die out or go dark through some other means, which leads to some interesting models of intergalactic colonization. "In certain circumstances, however, when civilizations are close enough together in time and space, they can come into contact and when this happens the cross-fertilization of ideas and cultures allows them both to flourish in a way that increases their combined lifespan. ... Bezsudnov and Snarskii say that for certain values of these parameters, the universe undergoes a phase change from one in which civilizations tend not to meet and spread into one in which the entire universe tends to become civilized as different groups meet and spread. Bezsudnov and Snarskii even derive an inequality that a universe must satisfy to become civilized. This, they say, is analogous to the famous Drake equation which attempts to quantify the number of other contactable civilizations in the universe right now."

Comments

My take

[Black Parrot]

Them that advertise get eaten.

Re:My take

[nitehawk214]

In spite of all that, you still think "them that advertise get eaten"

Fascinating.

No no, he is saying we will send advertising executives to the alien overlords as sacrifices.

Re:My take

[Wolvenhaven]

Alastair Reynolds wrote a series called Revelation Space which is about a machine swarm intelligence designed to destroy all life that goes outside their solar system because it prevents a galactic catastrophe trillions of years in the future. The machines leave races alone of they stay on their planet, but if they start moving through space and colonizing other worlds, they swoop in and eradicate them.

Re:My take

[Omestes]

Unless you think those random bits of organic gunk might grow up to be a threat to you someday. Best to destroy or co-opt them while it's still trivial to do, rather than wait for a potential rival to grow strong feisty.

Or save their souls. We also ignore the fact that any space-faring aliens might have the same stupid hang ups as us, and be doomed to repeat our history.

If, by some stretch, we managed to get into space, and found an intelligent species you can be sure that various sects of religious wackos will quickly try to convert them to Earthly religion. And probably, judging how these things historically worked, slaughter most of the in the process (in the name of progress and for their own good).

Re:My take

[thesandtiger]

Or (insert idea here) - the number one rule of alien life is that it will be alien. We human beings on Earth have a hard enough time understanding people who merely have different cultural underpinnings in their world view; imagine what a fundamentally different biology would yield for misunderstandings.

The only thing I see being similar regardless of the origin of species would be that the other intelligences we meet will be the survivors of an extremely long competition with other species on their world, whatever that means.

Re:My take

[thesandtiger]

What's amusing is that you seem to have an unprovable belief that religion is a disease to be cured is somehow obvious.

The fact that a majority of the people on Earth disagree with you demonstrates not only that it isn't obvious, but that you are probably just as irrational in your beliefs as those people are in theirs. But at least they have the intellectual honesty to admit it's faith.

I'm not remotely religious, but I'm also not so disingenuous that I'd dismiss a majority of humanity as somehow suffering from a disease that needs to be cured. For many people faith fills a void; I think rather than the idea that faithless people are somehow evil, faith helps people who might otherwise be evil because they need some system larger than themselves to believe in do good things. Why would something that prevents a lot of people who would otherwise do things harmful to the species need to be cured?

Re:My take

[tehcyder]

Hawking's a moron.

Seldom can that unpleasant word have been more inaccurately used. He may be totally wrong about many things, but one thing is for certain, and that is that Stephen Hawking does not have a below average IQ.

Maybe it's as simple

[Anonymous Coward]

As the speed it would take to get nearby stars in a short period of time is just not physically possible no matter how advanced you are and no civilization has yet wanted to spend 500 years getting here.

Re: Maybe it's as simple

[Black Parrot]

and no civilization has yet wanted to spend 500 years getting here.

One of the arguments offered regarding the Fermi Paradox is that "if each colony established two more colonies, the exponential growth would fill up the galaxy relatively quickly". However, that presumes that the members of the colonizing species would be willing to live their whole lives just to accomplish someone's Grand Plan. Intelligent colonists would (I presume) be more interested in making their own colony sustainable and life there comfortable.

Re:Maybe it's as simple

[painandgreed]

As the speed it would take to get nearby stars in a short period of time is just not physically possible no matter how advanced you are and no civilization has yet wanted to spend 500 years getting here.

That makes some big assumptions on not only the culture of alien races but also their life span. While it might be true of humans, we have no idea what the life span of an alien might be, what their interests are, or what their civilizations value. If we were dealing with a race that usually exists in solitude with a thousand year life span living on an overpopulated world, being on a ship by yourself for the next 500 years might seem like not only a blessing but very doable. Of course, the same race might not have any interest in contacting another race. On the other end, if human life span is on the long side of things, it may make it even less likely they'll try and leave on a great trip.

Re: Maybe it's as simple

[Chris Burke]

No it doesn't. It merely assumes that a majority of them would eventually become wealthy enough to afford to create a colony or two and would do so just as their parent did. You can give each colony a thousand years to mature and still fill the galaxy pretty damn quickly.

Right but the very fact that they are wealthy and advanced enough to create multi-generational colony ships makes me wonder why they would want to. The only obvious one is population growth exceeding the capacity of their world, but look at our world (as we naturally must for all such predictions): The richest portions of the world are the ones with the lowest population growth, including negative. People traditionally had many children because of 1) lack of birth control 2) needing extra labor for their farms 3) high mortality rate among children from illness etc. That only leaves culture as a reason to reproduce beyond replacement rate, so sure maybe the Space Catholics will have population issues but otherwise it seems plausible that wealthy and advanced civilizations will stabilize not grow unbounded.

Then what? Resources? To even make the colony ship work I'm going to assume they have a Mr. Fusion, and once you have that you can do a hell of a lot with the resources of just one system (especially given a bounded population) and every energy-intensive recycling technique is suddenly much more feasible. Sending a small fraction of the population off in expensive colony ships is only going to exacerbate a resource problem anyway. Exploration, sense of adventure? Explorers are people who want to explore, not people who want to maybe enable their great-great-grandchild to explore.

I'm not saying it isn't possible. I'm saying that the answer to the Fermi "Paradox" could be as simple as: Maybe the assumption that civilizations will engage in exponential galactic colonization endeavors is wrong.

Re: Maybe it's as simple

[thesandtiger]

Even if you posited a 10000 year development time before a colony could successfully send out just 1 other colonizer, and another 10000 year development time before it could send out another, you still wind up filling up the galaxy REALLY fast. Even if 9/10 of those colonies fail to sprout (so let's call it, effectively, 100k years per new colony), in just over 5 million years (a cosmic blink of an eye) you have over 10^15 colonies. Even if it was 1 in 100 colonies that succeeded, you're still just talking about 50 million years.

Look at human history over the last 5000 years - we've gone from pre-technological to being on the verge of being able to break out of our solar system (relatively speaking, assuming we survive, we should be able to get out of town within the next 100000 years if we aren't dead). A colony on a future world would have all that technology and knowledge already developed - I'm going to say that, if we do get to another world, it'll take us WAY less time to fill it up and move on than it will take us to do this.

Re: Maybe it's as simple

[Curunir_wolf]

but look at our world (as we naturally must for all such predictions): The richest portions of the world are the ones with the lowest population growth, including negative. People traditionally had many children because of 1) lack of birth control 2) needing extra labor for their farms 3) high mortality rate among children from illness etc. That only leaves culture as a reason to reproduce beyond replacement rate

No, there are other reasons as well. In fact this analysis is very subjective - there are no other examples of life forms that slow their own reproductive rate for any reason other than lack of resources.

You raise an interesting point, though. One that was examined in "The Mote in God's Eye" by Niven and Pournelle. The sentient species in question spoiler alert - if you haven't read the book was unable to slow its reproductive rate, due to the way they had evolved their reproduction. So they colonized their own solar system (extensively), but were unable to advance far enough to travel elsewhere. The conflicts of resources was dramatic, so they basically ended up blowing themselves back to the stone age over and over again, only to rise again, mine resources, re-colonize the solar system, escalate their resource battles, and destroy themselves again.

Seems a bit of a stretch, but maybe we're better at birth control that most...

Re: Maybe it's as simple

[JSBiff]

What, wait, you're assuming every star system is only about 4 light years from it's neighbor *and* that every star system has a useful/suitable planetary type for the type of life that civilization is composed of? Sure, you might be able to cross the 4 light years to Alpha Centauri (or wherever), but is there gonna be a planet you can live on at the end of the trip?

I think your 'filter' is simply that in reality, the distance to the nearest suitable planet will usually be much greater than 4 light years. Granted, our technology is still developing, but it seems to me that it's a very hard engineering task to create a vessel which is suitable to contain life, and that will not degrade so much in 1000 or 2000 years (or whatever the travel time is) that everyone on board dies. Everything wears out, eventually. Although, I suppose in space, things might wear out a lot slower with no friction (well, there is the small matter of the Interstellar Medium abrading away at your hull like a sandblaster).

I'm not saying these aren't problems that can't be overcome, but 4 light years seems daunting enough - what if the nearest earth-like star is 100 light years away? 200?

Re: Maybe it's as simple

[Chris Burke]

What about Von Neumann Probes? Why haven't we even seen any of them? They would hypothetically proliferate much faster than giant colony ships and should also be here by now.

Heh. Aside from all the reasons that apply to alien radio signals or colony ships... And the same question of "would they necessarily want to?" I personally think it would be the height of irresponsibility to send out fully autonomous self-replicating probes. There's a thin line between a Von Neumann Probe and a Slylandro Probe. I would like an operator in the loop that verifies that the life-detection instruments are fully working before giving the go-ahead to eat and reproduce in a new system. But aside from that?

How do you know there isn't a probe coasting past our solar system, checking us out, right now as we speak? It's not obvious that we could even see a probe at that distance even if we knew exactly where to look.

That's why I ultimately find the Fermi Paradox silly to think of as a real mind-boggling paradox or proof of alien non-existence. "Why haven't we already seen solid evidence of aliens?" is so ridiculously far from being the same question as "Why isn't there evidence of aliens that could hypothetically be seen by us?" that taking the former to imply the latter is lunacy.

The idea that we've done an exhaustive search of our little neighborhood of the galaxy and concluded that nope, there's no life here, is just completely divorced from reality.

I have a better paradox

[blair1q]

If they are as intelligent as we think they are, won't they take one look at us and pretend they're not home?

Basic assumptions

[icebike]

The bit quoted as "Eventually die out and go dark" apparently comes from this quote in the second link:

Their approach is to imagine that civilisations form at a certain rate, grow to fill a certain volume of space and then collapse and die. They even go as far as to suggest that civilisations have a characteristic life time, which limits how big they can become.

However, this deals only with civilizations and not intelligent beings. The Civilization may collapse, after expanding to multiple worlds, but that does not mean that everyone on these planets dies. The would live on to create new civilizations.

Using an admittedly imperfect Earth analogy, the collapse of the Roman or Mayan empires din not lead to the extinction of humans, merely a pause in the development of civilization among that species, (us).

So EVEN if the basic assumption is correct, you would still expect to see many inhabited worlds, populated with remnant people having "arrival myths".

They may have once held knowledge of how to build ships, but deciding instead simply to sit tight, and not draw attention to themselves for a long enough period for any ship building knowledge or desire to wane. But new civilizations and technology would sooner or later arrive on these worlds.

When you start with a flawed and pessimistic assumption, it seems natural that you might arrive at a dismal conclusion.

Re:Basic assumptions

[HiThere]

But by the time the civilization collapses it's used up all of the readily available hydrocarbon deposits and metal deposits. (Civilization may require readily available copper deposits to be jump-started.)

So unless you can read the old CDs...or whatever storage medium replaces them...you can't learn enough to make a technological civilization out of what's left. You can probably go quite far with ceramics, glasses, etc., but none of those lead to electronics. And if you can't get to electronics you can't extract specialized materials out of low-value ores. (Well, possibly you could fractionally distill them...but just try doing that to extract iron. Zinc [zinc oxide?] you could get that way, though. Even if you get them that way, you get compounds, not metals. You need electricity to extract most metals from their compounds.)

I'm not sure you get a second chance at a technical civilization.

Re:Basic assumptions

[icebike]

But again, you assume collapse due to material exhaustion, which, even for a very OLD civilization would not universally be the case, especially one that migrated to other planets.

Why would a planet be colonized in the first place if there were insufficient materials for self support?

By the way: There is no exhaustion of copper or metals, as any gaze into a junk yard will reveal. In fact we make mining significantly easier for future generations by concentrating all of our waste materials. And any civilization capable of interplanetary migration would be been off hydro-carbons as a primary energy source for eons.

Hyperspace Bypass

[schmidt349]

What do you mean, you've never been to Alpha Centauri? For heavens' sakes, mankind, it's only five light-years away. Look, I'm sorry, but if you can't be bothered to take an interest in local politics that's your own lookout. Energize the demolition beams.

Apathetic bloody planet... I've no sympathy at all.

Re:Population of universe is zero.

[Anonymous Coward]

Therefore, there must be a finite number of inhabited worlds.

The logical deduction breaks down here. If there are an infinite amount of worlds, and you take away a few that don't have life, you're still left with infinity. (Warning: The maddening concept that the infinity of all planets is larger than the infinity of planets with life may harm your brain. Viewer's Discretion is Advised).

Even if you said "half", "a quarter", "1%", "0.0000000001% of those planets have life", the number you're left with is still infinite. The only way you could say that the limit of the number of inhabited planets in the universe as the number of planets approaches infinity is if you have a finite number of planets with life to begin with. Right now we can say that though, as we only know of one, Earth, but it still relies on the assumption that there are an infinite number of planets, which would mean the universe has infinite mass, which doesn't really make much sense.

Alternative Interpretation

[camperdave]

Here's an alternative: Perhaps we are the First. Perhaps humanity is the first culture to rise to the point of being able to leave their home planet, even for a short while.

Re:Or maybe we are living in a simulation...

[Surt]

Does anyone who has ever rubbed their eyes still doubt that we are living in a simulation? I mean, why else would you wind up with an input error grid?

Maybe

[rossdee]

Democracy is more common than we thought, and the aliems governments cut their funding too.

No start of time in the Drake equation

[grimJester]

The time needed for our solar system to develop life was more than a third of the age of the universe so far. Extending the Drake equation to replace communication time before extinction with odds of spreading to the next star before extinction and replacing probabilities with average time taken would make far more sense than the original one.

We're probably just the first advanced civilization in our galaxy. No Fermi paradox, no odd extinction events, no improbably rare Earth. Why would it be impossible for civilizations to travel to another star and why would the typical time to interstellar travel be short enough that current formation rate of generation I stars is a more limiting factor than amount formed since the Big Bang?

Re:No start of time in the Drake equation

[TheTurtlesMoves]

That the *hard step* is the evolution of complex life, is one of the proposed solutions to the Fermi paradox. We have some evidence to support this. Basically everything was single celled, then one single cell life form swallowed another and made it a DNA management machine (nucleus). After than the explosion of complex multicellular life happened. This appears to have taken billions of years. Its quite possible that such an event is "rare" in the sense that it always takes a really long time even in favorable conditions.

Some more thoughts on the subject

[erichill]

There's been a lot of argument that "close in space *and time*" is precisely the problem. In the cosmically vanishingly small time of a million years ago, we weren't very interesting. If we're still around in a million years, we probably wouldn't want to detectably approach anyone at the level that we're at now. There's also evidence that we're heading towards "going dark" as a result of using more efficient communications so there will be an inner surface to our radio sphere of influence. There may be other things to look for, like the gamma ray signature of antimatter powered interstellar vehicles. We wouldn't see anybody on a ballistic trajectory. I'm rather taken by arguments that suggest that really advanced cultures won't want to be very spread out because of communications latency. See, for instance, this by Cirkovic and Bradbury.

As already mentioned, there is the possibility that we're the first [in our light cone].

Communicate first?

[CdBee]

I'd have thought, however risky we are to meet, any civilisation that's aware of us and monitoring would probably start with a generic 'hey guys, want to chat? Check where this signal is coming from if you want to know who we are'

it might not only be human society that thinks turning up unannounced is poor form.

Why are we assuming E/M transmission?

[sconeu]

Perhaps advanced civilizations are not using EM transmission (radio/light), but some other form of communication that we are unable to detect.

Yes, Trek is fictional, but to use it as an example: We wouldn't detect Starfleet because they use "Subspace communications" instead of radio.

It's time and distance as much as anything else

[Todd Knarr]

We generated our first real radio signals sometime around 1894, give or take. That means that we are completely and utterly invisible in the radio spectrum to any civilizations more than about 116 light-years away from Sol. Our radio signals simply haven't had time to reach them yet. And the same thing applies in reverse: if an alien civilization began transmitting radio signals 200 years ago but they're more than 200 light-years away from us, we won't be able to see them because their signals haven't had time to reach us yet.

That defines the outer edge of the visibility shell. There's also an inner edge. As a civilization develops, it eventually stops transmitting radio signals as it first gets more efficient at transmitting radio (moving from pure broadcast to directed transmissions and then refining their ability to direct the transmission into tighter and tighter beams) and then starts using things other than radio. If you start listening after the last of their detectable broadcasts has passed you, again you can't see them.

So when you're asking "If there are as many civilizations out there as the equations predict, why can't we detect them?" you also have to take into account the fact you're likely only physically able to detect a fraction of the civilizations that may exist. The rest are either too far away for their signals to have reached you, or they've been around long enough that you weren't listening when the last of their detectable transmissions passed your planet.

What the paradox doesn't take into consideration

[Locke2005]

Life is common, but so are cataclysmic events. Very few life forms evolve higher intelligence. After a point intelligence isn't very useful for survival; we evolved intelligence far beyond that needed for mere survival because we used it for social competition since smarter people had more chance of breeding (hard as that is to believe today).

Of the few life forms that evolved higher intelligence, very few of them would have won the race to establish viable self-sufficient colonies off-planet before a cataclysmic event wiped out their planet, solar system, or galaxy.

And finally, of course, the obvious -- any really intelligent being wouldn't go around hanging up neon "I'm here!" signs to broadcast their location to potential predators.

Finally, it may be that really advanced civilizations discover a "party line" that enables faster than light communication, which would enable most of the benefits of interacting without other species without the expense of physically traveling to them or the risk of giving away one's own location. In which case, they are merely keeping a low profile while waiting for us to also discover this communications method.

Bandwidth efficient communication looks like noise

[Ungrounded Lightning]

My own take on the Fermi paradox comes from the observation that modern radio communication systems - spread spectrum and ODFM - approach the Shannon limit of the bandwidth's information carrying capacity. As they do that, they approach the appearance of pure noise.

Earlier transmission systems, such as AM, FM, and analog broadcast's AM/FM hybrid, involve massive inherent reundancy and low bandwidth utilization. This makes their existence detectable (even if not fully decodable) at interstellar distances and at the resulting far worse signal-to-noise ratio than their intended receivers experience. Spread-spectrum and OFDM systems (and no doubt others yet to be invented) fill their assigned bandwidth with a close approximation to white noise, with only a small amount of redundancy to allow the receiver to detect the existence of the signal and synchronize with it. (Even the redundancy from the forward error correction is sufficiently complex that at appears as noise if the particular scheme is not being looked for.) This is why, when the signal-to-noise ratio of a digital signal becomes excessive, the reception drops out completely rather than becoming noisy.

Bandwidth is limited by physice, but the potential valuable uses of it are limited only by imagination and cost. So other radio-using civilizations seem likely to follow a similar path of squeezing as much information as technology allows into their signals.

If this is the case, the L term in the Drake equation ("the length of time such civilizations release detectable signals into space") becomes a measure, not of the lifetime of the civilization after it begins to use broadcast radio, but of the time from such use to the time it is supplanted by highly-efficient but not-readily-detectable shannon-limit-approaching signals.

When estimating the number of intelligences in this galaxy using the Drake equation, L was ballparked at 10,000 years. But consider broadcast TV here on Earth (the main telltale, emitting far more power per station than audio radio): Excluding early experiments the first regularly scheduled TV broadcasts started in 1930 - and the Analog Cutoff (where most high-power analog TV stations were shut down to free the bandwidth for other purposes) is in progress now, with the US terminating all full-power analog TV broadcast in 2009, just 80 years after the first signals from that first broadcast-service station.

So I have no feeling of loneliness just because we haven't happened to hear any civilizations in the narrow time slot when they might send DETECTABLE broadcasts.

Re:Population of universe is zero.

[Brucelet]

(Warning: The maddening concept that the infinity of all planets is larger than the infinity of planets with life may harm your brain. Viewer's Discretion is Advised)

A slight correction: these two infinities (assuming they even are infinite) could be the same size even when the set of inhabited planets is a subset of all planets. Infinities are really weird.

My Own Theory to explain the Fermi Paradox

[Curunir_wolf]

I have a different theory.

I think that in many cases, civilizations reach a point where a small group can convince the mass of population that they have to alter their lifestyles to prevent their own advancement from destroying their environment. Thus cowed, the rulers, without any motivation for advancing the species, and living in luxury by the labor of a vast cadre of dependent and ignorant masses, push the rest of the civilization into more primitive lifestyles.

Preserving this stable lifestyle becomes and end itself, all ambitions of extra-planetary exploration forgotten. Eventually, the civilization runs out of local resources, too late to escape their own gravity well, and die off never having attained their potential.

What do you think? I call it the Enviro-Gorbama effect.

Re:Or maybe we are living in a simulation...

[Nethead]

I can't tell you but I know it's mine.

You'll go blind

[Hognoxious]

What do you see if you close your eyes and rub hard?

I don't see anything, but my hand feels sticky.

So what you're saying...

[warrax_666]

So what you're saying is that those people who have faith would go around murdering their neighbors, raping and pillaging, etc. if they didn't have "faith"?

That's complete bollocks and you know it.

Good people are good and bad people are bad. Religion is a system of control which can be (and has been) leveraged for both good and bad.

Re:Their take

[rufty_tufty]

Part of the fermi paradox assumes that a planet that is suitable for life will develop life.
Therefore any planet we would want to live on will already have life there. If it doesn't have life on it then it's not suitable for us. Add to this there will probably be other planets that aren't suitable for us that have life on them as well and that's a lot of competition for resources.
Now I personally don't buy that we would want to live on planets when if we have the technology to build spaceships we have the technology to build orbital colonies that have many advantages to the upwardly mobile space civilisation.
Now all of this is unless it is easier to devastate than it is to build those orbital colonies. My hunch is that humans like to hunt and would view the natives similar as how we view lions at the moment - there are plenty of people who'd love to hunt them given half a chance provided they see them as inferior life forms.
So yes I see that contact with an alien species would probably end badly for one of the parties; but it will only be so if it is easy and convenient or religiously necessary.
And that is all without the military mindset classifying them as a risk and therefore exterminating them for "our own long term protection".

Re:Or maybe we are living in a simulation...

[Paul Fernhout]

"You jest..." Well, not exactly. I don't know what to believe for sure. That is just one of the obvious possibilities at this state of our understanding of information processing. It may be true, or it may not. Enumerating it as a possibility at least is a bit of an antidote to fundamentalism of other kinds. I think you may be right on the bugs though. :-)

I've thought about writing a sci-fi novel based around three interacting groups (taking off on Arthur C. Clark's ideas of any advanced technology is indistinguishable from magic):
* Those who have expanded human consciousness in a transhumanist technical nanotech/biotech direction and can do magical-looking things like with nanotech (like when nanites rebuilt the Red Dwarf).
* Those who have found this debugger link or just a bug and can affect reality in magical seeming ways (so, like Harry Potter or Earthsea, where words an incantations and symbolic movements and symbolic devices like wands are combined to create patterns that invoke complex programs written in arcane symbols, such as from "lumos" causing light to all sorts of complex spells invoked in complex ways -- maybe with a high degree of secrecy involved in who makes these things and who is told about them).
* Those who have just expanded humanity in a brute-force sort of way throughout the solar system and beyond through self-replicating space habitats duplicating themselves from sunlight and asteroidal ore, and maybe also have recently learned to tap zero-point energy and so create energy and matter in empty space (so, they can duplicate things out of thin vacuum as it were).
I have no idea where that would go. But those are the major sorts of "magic" things I can imagine in our future, and all are hard-sci-fi "plausible". Would the mystery of consciousness be an underlying theme?

In keeping with the theme of this article of interacting "alien" civilizations in space, maybe it could be humans plus two other "alien" races from other stars that meet, each with a different technological approach as above, and they try to understand each others tech? On the other hand, it's likely that humans will radiate into multiple species if we expand, so the "aliens" may just be some form of us, in terms of, say, a cyborged person-whale hybrid that travels through space, or human mental patterns copied into robots (and then changed further in there?), and biotech variations, and Amish-like "pure strain humans" (a term used in the Gamma World role playing game of the 1980s which had a diversification of human forms). So, there could be three very different species of humans to go along with those three technological approaches.

Maybe ZeroExistenZ's other comment on Terry Pratchett has gotten me to think again on this. But I don't have the story-telling skill or attention to humanistic detail of someone like the late James P. Hogan. I just finished rereading his "Star Child" to my kid as a way to honor all the great stories he had written, and how they effected my own life in a positive way. His "Entoverse" has aspects of what you suggest -- computational processes in a big computer start moving out into the real world through what one might think of as a sort of "bug" in the computer system.

Your point on bugs etc. raises another issue. At what point is something running on a virtual machine really just a contained item? If it can do things that affect the outside world, then patterns in it can migrate outwards into an enclosing virtual machine (or "real" machine). So, sims evolved in a VM could be copied into robot bodies (or even biological bodies) in the outer enclosing world. Or those in an economic simulation used to decide policy in the outer world could choose to act differently to effect the economics of the outer world (or the morality or whatever is being learned through simulation).

I can wonder what the ethics might be in relation to simulating worlds? I think about that even now, in playing computer games with "sprites". We don't really know what c