# Is the Fermi Paradox becoming more acute?
**URL:** https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574
**Category:** Great Debates
**Created:** [July 10, 2016, 4:35pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574 "2016-07-10T16:35:09Z")
**Posts on this page:** 20
**Page:** 9
### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [May 30, 2020, 3:25pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/161 "2020-05-30T15:25:23Z")
> [@eburacum45](#):
>
> The argument against this is the same one as the the argument against the Brandon Carter Catastrophe;
>
> We can only ask this question now, before we become a galactic species, because we \* don’t know the answer\*.
I think you’re misunderstanding the point I was making. Whether we know of other civilizations or not doesn’t have any effect on the probability of being born within a certain subset of human beings to ever live, so the answer to the question whether there are any other civilizations out there has no effect on the question of why we’re born at this particular moment in human history. These are two independent issues; both, however, given the most natural assumptions about the distribution of intelligent/conscious beings through time and space, demand an explanation. The Dark Forest, if true, would provide an explanation for both.
> [@](#):
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> Every advanced alien civilisation has had a brief period in its history, just before it starts to expand into the universe, when they didn’t know the answer to the Fermi Paradox, and when the Carter Catastrophe loomed large and close in the future.
Exactly. Hence, assuming an even distribution over the possible beings to ever live, one should be surprised to find oneself alive within this brief period, rather than within the period in which most members of any given species are alive, provided there ever is a jump to the stars.
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### Author:  [@Mijin](https://boards.straightdope.com/u/Mijin)
#### Post date: [May 30, 2020, 4:00pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/162 "2020-05-30T16:00:41Z")
> [@wolfpup](#):
>
> There are some very good and interesting analyses in this thread. My only problem with the Fermi “paradox” is calling it a paradox at all; as someone already noted upthread, it’s more of an interesting question than a paradox. Why does there _ **appear** _ to be no life out there in our observable universe? There are myriad possible explanations.
Right. I think the word “paradox” unfortunately leads to the misconception that Fermi, or anyone who alludes to the paradox, believes that intelligent life must be numerous or cannot think of a single plausible reason why we haven’t been visited.
So you get countless threads and posts where people say, essentially, “The Fermi Paradox is dumb because I can think of a plausible explanation why we haven’t seen ETs”.
Another issue with the paradox is it can imply that there’s only one big mystery when it comes to ET life, when in fact there are very many interesting questions we can ask, with the Fermi paradox being an ultimate question resting on many others.
The Drake equation makes this a bit more explicit.
> [@Half Man Half Wit](#):
>
> In fact, one can place bounds on the expected total number of humans to ever live given the fact that we’re among those born right now. This is known as the Doomsday Argument: essentially, the probability we’re within the first, say, 50% of humans to ever be born, is 50%. Hence, after us, with a likelihood of 50%, there’ll be about as many humans as have lived up to now.
I’ve never really found this philosophical argument very convincing. I don’t see any reason to believe my date of birth was random in some metaphysical sense, and if this idea worked, then we get weird results:
- Prehistoric humans might incorrectly conclude that humans will never live in large cities
- The Simulation Hypothesis would seem to necessarily entail; if the time and place of my birth is a random pick from the set of all sentient minds then it’s vastly more likely I’d be born in a simulation than even a real human civilization of a billion star systems. And if we’re asserting we’re in a simulation, we’re not making claims about the real universe (and any dearth of ETs) at that point.
Finally, any argument that concludes with “X is unlikely” can be responded to with a shrug. Unlikely things happen.
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### Author:  [@eburacum45](https://boards.straightdope.com/u/eburacum45)
#### Post date: [May 30, 2020, 4:02pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/163 "2020-05-30T16:02:31Z")
That only works if there is nothing special about the current era. We can only discuss the Fermi Paradox and the Carter Catastrophe because we don’t know the reason for the paradox, or the eventual size of the future human population. If and when we expand our civilisation to the stars and count our population in the quadrillions, we will have a better answer for both questions.
As I said, there is a period in the history of every expansive civilisation (between the invention of mathematics and the development of interstellar flight) when they are ‘special observers’ so cannot predict the future accurately. We are currently in that phase, and if we manage to avoid the Carter Doomsday and gain access to the stars we will no longer be limited in that way.
Perhaps the chances of avoiding the Carter catastrophe and spreading to the stars (thereby finding an answer to the FP) are small, but that doesn’t mean we should give up.
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### Author:  [@Mijin](https://boards.straightdope.com/u/Mijin)
#### Post date: [May 30, 2020, 4:20pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/164 "2020-05-30T16:20:24Z")
Sorry to post so much into this thread, but I also wanted to recommend the [Isaac Arthur series](https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh8TTOnCgRkLdU) of youtube videos (and soundcloud podcasts), for anyone who is interested in the Fermi paradox.
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### Author:  [@Trinopus](https://boards.straightdope.com/u/Trinopus)
#### Post date: [May 30, 2020, 4:25pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/165 "2020-05-30T16:25:33Z")
> [@Tibby](#):
>
> . . . if inter-stellar, or inter-galactic travel is even doable, we must assume it would be a very costly endeavor for any civilization. . . .
Any civilization? Like Dyson-sphere builders? A handful of Von Neumann probes wouldn’t even be visible in the budget.
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [May 30, 2020, 6:02pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/166 "2020-05-30T18:02:31Z")
> [@Mijin](#):
>
> I’ve never really found this philosophical argument very convincing. I don’t see any reason to believe my date of birth was random in some metaphysical sense, and if this idea worked, then we get weird results:
Wouldn’t it be much weirder if there were some metaphysical necessity for you to be born right here, right now? I’m not even sure what that would mean, to be honest. I mean, there’s not (unless one believes in immortal souls) some sort of transcendend ‘you-ness’ that could be incarnated in this specific slot. The argument isn’t saying that there’s some kind of cosmic coin toss that dictates whether you would be incarnated as human number 3 or 3 billion or 3 quadrillion; there’s just a certain number of human beings, of which you are one. That you should find yourself to be one of those within the first 5% then has a likelihood of 5% solely because that number of humans is 5% of the total to ever live; nothing more.
> [@](#):
>
> - Prehistoric humans might incorrectly conclude that humans will never live in large cities
No, they’d completely correctly conclude that the likelihood is low that so many humans would ever exist; but as you say, unlikely things happen.
Another way to think about this is that the vast majority of those making this argument—i. e. that they’re part of a large subset of the total population of minds—will, in fact, be correct; hence, that one is correct when making this argument is the stance more likely to be right.
> [@](#):
>
> - The Simulation Hypothesis would seem to necessarily entail; if the time and place of my birth is a random pick from the set of all sentient minds then it’s vastly more likely I’d be born in a simulation than even a real human civilization of a billion star systems. And if we’re asserting we’re in a simulation, we’re not making claims about the real universe (and any dearth of ETs) at that point.
But that’s exactly the sort of reasoning that leads to people thinking the simulation hypothesis is worthwhile at all—if the simulation of minds is possible, then we’re far more likely to be simulated minds, than real ones, because the number of simulated minds ought to vastly outstrip that of real ones. That’s the same argument as saying, if we ever make it to the stars/exist for a prolonged time at the maximum carrying capacity of Earth, we’re most likely to find ourselves existing during that period of time, rather than the one we actually find ourselves existing in.
> [@](#):
>
> Finally, any argument that concludes with “X is unlikely” can be responded to with a shrug. Unlikely things happen.
Of course. We could just have gotten ‘lucky’, as things stand. But by definition, that’s the more unlikely explanation—it’s not the way you oughta bet, in other words, even though you might bet that way and win.
> [@eburacum45](#):
>
> That only works if there is nothing special about the current era. We can only discuss the Fermi Paradox and the Carter Catastrophe because we don’t know the reason for the paradox, or the eventual size of the future human population. If and when we expand our civilisation to the stars and count our population in the quadrillions, we will have a better answer for both questions.
Sure, but I fail to see how that impacts the argument. Say we find ourselves in the far future, mankind having spread to the stars; we’d just say, well, that’s what we ought to have expected—pretty much every mind to ever exist will find itself in these circumstances.
Hence, the mere fact that we, at present, don’t find ourselves in these circumstances means that we’re part of what ought to be a very small subset of all the minds to ever exist. Now, either, we just got lucky—or, the subset of minds we’re part of is a much larger part of the total. The former is unlikely to be correct; and the latter means we won’t ever spread to the stars, and neither does anybody else, and hence, we shouldn’t expect to see alien civilizations.
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### Author:  [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)
#### Post date: [May 30, 2020, 6:43pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/167 "2020-05-30T18:43:39Z")
> [@wolfpup](#):
>
> The idea that we are the only intelligent life in this galaxy alone is absurdly unlikely. It’s like picking up a seashell on the beach and asking, I wonder if this is the only one in the world, the only one that has ever existed or ever will? Not bloody likely.
Not sure why you would choose such a bad analogy. One shell means that there would have to be a line of descent leading up to said specimen, meaning that finding another, past or present, would logically follow.
Instead, each planet, totally independent of the others (so we can’t assume any lines of interrelated descent, unless space panspermia is a {the} thang, which it could be), would have to run its own gauntlet of filters, the number & breadth of which should beggar the imagination. It’s more akin to seeing a dice come up 6’s 3,000 times in a row. The Drake Equation is an attempt to quantify all of that, but he had only what 7 factors? When each factor actually has their own subsets of innumerable factors, each of which has to come up snake eyes. This is NOT to suggest that our way is the only way of course, or that each factor is independent of the others (some undoubtedly are, some aren’t), but just that the odds are utterly staggeringly against ANY civ springing up, anywhere.
In any event, about the “paradox” here, yeah, our effective blindness & ignorance about the wider universe is all said paradox is really pointing at, for the moment.
That said, I don’t think there is another civilization anywhere in the universe.
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### Author:  [@Voyager](https://boards.straightdope.com/u/Voyager)
#### Post date: [May 30, 2020, 6:46pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/168 "2020-05-30T18:46:09Z")
> [@Half\_Man\_Half\_Wit](#):
>
> Sure, but I fail to see how that impacts the argument. Say we find ourselves in the far future, mankind having spread to the stars; we’d just say, well, that’s what we ought to have expected—pretty much every mind to ever exist will find itself in these circumstances.
>
> Hence, the mere fact that we, at present, don’t find ourselves in these circumstances means that we’re part of what ought to be a very small subset of all the minds to ever exist. Now, either, we just got lucky—or, the subset of minds we’re part of is a much larger part of the total. The former is unlikely to be correct; and the latter means we won’t ever spread to the stars, and neither does anybody else, and hence, we shouldn’t expect to see alien civilizations.
Except that every human who lived more than 100 years ago got “lucky” in the same way. This implies that there is something wrong with this argument - they all couldn’t get lucky, could they?
What’s wrong with it is that there is an assumption of the total number of humans built in. We are only not lucky if our generation includes a large proportion of the humans who ever will live. We are “lucky” like the ancients, if our generation does not. There is no way of knowing, so arguments predicting the total population based on assumptions on what the population will be are fallacious.
BTW, the simulation argument must be put forth by those who have never seen the power bills of Google and Facebook. Simulations take energy. A simulation of the entire universe to the level of granularity we see would take vast amounts of energy. If that universe does a simulation of a universe, double the energy. And so on, ad infinitum.
Plus, as an old simulator writer, this would be a dumb shit way of finding out whatever the simulation was supposed to discover. It’s not all that different from the argument against creationism that if God made the universe for us, he didn’t have to make it so damn big.
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [May 30, 2020, 6:57pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/169 "2020-05-30T18:57:14Z")
> [@Voyager](#):
>
> Except that every human who lived more than 100 years ago got “lucky” in the same way. This implies that there is something wrong with this argument - they all couldn’t get lucky, could they?
Of course. In fact, exactly the expected proportion of people making this argument will get ‘lucky’. Suppose there’s 100 people ever born. One of them thinks, I’m within the final fifty percent of people to ever been born. What’s the likelihood they’re correct? Well, exactly 50%, of course. So, if they’re within the first 50, they’ll get lucky, and within the final fifty, they’ll be right. The same works for every other percentage. It’s just counting, really.
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### Author:  [@Larry\_Borgia](https://boards.straightdope.com/u/Larry_Borgia)
#### Post date: [May 30, 2020, 7:18pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/170 "2020-05-30T19:18:33Z")
> [@Trinopus](#):
>
> Any civilization? Like Dyson-sphere builders? A handful of Von Neumann probes wouldn’t even be visible in the budget.
You are assuming a Dyson sphere is possible.
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [May 30, 2020, 8:33pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/171 "2020-05-30T20:33:44Z")
> [@Voyager](#):
>
> BTW, the simulation argument must be put forth by those who have never seen the power bills of Google and Facebook. Simulations take energy.
And well, while I don’t think the simulation argument works, I don’t think it’s because of energy requirements. In principle, any computation can be made reversibly, thus consuming arbitrarily little energy. Only deleting of information needs to consume energy, so if you just never do that, you’re good. (Not to mention that this energy is orders of magnitude below that achieved by present-day computers.)
Moreover, this assumes that our laws of physics, feasible energy budgets and the like, ought to apply to our parent universe, so to speak, as well. But there’s obviously no reason for that to be the case.
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### Author:  [@Trinopus](https://boards.straightdope.com/u/Trinopus)
#### Post date: [May 30, 2020, 8:38pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/172 "2020-05-30T20:38:34Z")
> [@Larry\_Borgia](#):
>
> You are assuming a Dyson sphere is possible.
Are you, then, assuming it isn’t? What parameters and limits are you willing to place upon “any civilization?”
In any case, the first self-replicating probe need not be amazingly expensive. It might amount to a few tons of machinery and a few million lines of programming.
So I disagree with your claim at both ends: civilizations might be vastly more powerful than we can guess…and probes might be a lot simpler and cheaper than we can know.
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### Author:  [@Larry\_Borgia](https://boards.straightdope.com/u/Larry_Borgia)
#### Post date: [May 30, 2020, 10:07pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/173 "2020-05-30T22:07:10Z")
> [@Trinopus](#):
>
> Are you, then, assuming it isn’t?
Yes I am flatly stating it is a practical impossibility. There isn’t the energy or the material to make one. I will continue to hold this position until you or someone else can show me a blueprint.
ETA: I love SF. I’ve consumed a ton of it. But it’s a sub-genre of fantasy. A Dyson sphere is no more realistic than a baleful polymorph spell.
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### Author:  [@Tibby](https://boards.straightdope.com/u/Tibby)
#### Post date: [May 30, 2020, 10:36pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/174 "2020-05-30T22:36:28Z")
> [@Trinopus](#):
>
> Any civilization? Like Dyson-sphere builders? A handful of Von Neumann probes wouldn’t even be visible in the budget.
For your information, I have a Dyson Ball and use it daily. I got it at Home Depot.
Oh, Dyson Ball ≠ Dyson Sphere?!? …never mind…
Dyson spheres may be theoretically possible, but it’s a leap to assume they can and would be built by advanced civilizations.
Likewise, it’s assumed that the goal of advanced civilizations is to spread out and control as much of the universe as possible. Empire-building may be the goal only of small-brained people, like us (well, y’all, not me…😉
Empire building is already considered gouache on our planet and we’re barely more advanced than poop-slinging monkeys. Perhaps advanced civilizations are enlightened and just want to chill, toke Dune-spice and protect their corner of the universe from tight-assed intruders, like us (well, y’all, not me…😉
Rational civilizations may very well conclude, _“why should we bust our alien-asses spreading our seed throughout the universe when the Big Rip is coming in a mere 22 billion years?”_
22 billion is not in the same ballpark as infinity. 22 billion is not even that big a number in the big scheme of things. Bill Gates has more billions in dollars than that. In brane-years, it’s a mere drop in the bucket.
If we were dealing with infinities (time and space), then yes, Fermi is a paradox. But, we’re not. We’re dealing with a relatively small closed system of billions, not trillions, not quadrillions…
The universe is less than 14 billion years old and most of those years were too primordial to evolve advanced life.
There are ~2 trillion galaxies in our observable universe, but how far out can we really see signs of advanced civilization? An infinitesimal fraction of that, at best.
Why don’t we see signs of advanced civilizations beyond our planet? Because we can’t see far enough in time nor space.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [May 30, 2020, 10:37pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/175 "2020-05-30T22:37:40Z")
Radio may well be a transitory technology, but that doesn’t solve the problem. Fermi wasn’t asking “Why aren’t aliens talking to us?”. He was asking “Why aren’t aliens _right here_, on this planet?”.
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### Author:  [@Trinopus](https://boards.straightdope.com/u/Trinopus)
#### Post date: [May 30, 2020, 11:03pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/176 "2020-05-30T23:03:39Z")
> [@Larry\_Borgia](#):
>
> Yes I am flatly stating it is a practical impossibility. . . .
I don’t agree, but it isn’t necessary to my argument. You said “any civilization,” and I think that’s wrong, for both of the reasons I specified.
Tibby: I certainly can’t guess _why_ an advanced civilization would build a probe network… But could an intelligent alien guess why we’ve landed probes on Mars? If a thing is possible at all, then, given a large enough population, somebody is actually gonna do it.
(Which scares the hell out of me, given the number of ICBMs we have ready to launch…)
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### Author:  [@Mijin](https://boards.straightdope.com/u/Mijin)
#### Post date: [May 31, 2020, 3:26am UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/177 "2020-05-31T03:26:01Z")
> [@Half\_Man\_Half\_Wit](#):
>
> Wouldn’t it be much weirder if there were some metaphysical necessity for you to be born right here, right now? I’m not even sure what that would mean, to be honest. I mean, there’s not (unless one believes in immortal souls) some sort of transcendend ‘you-ness’ that could be incarnated in this specific slot. The argument isn’t saying that there’s some kind of cosmic coin toss that dictates whether you would be incarnated as human number 3 or 3 billion or 3 quadrillion; there’s just a certain number of human beings, of which you are one. That you should find yourself to be one of those within the first 5% then has a likelihood of 5% solely because that number of humans is 5% of the total to ever live; nothing more.
To me it’s a self-evidently silly argument; there is no cosmic waiting room where souls wait for which body they will quantum leap into, so no reason to think probability can be applied here.
But let me try another argument to convince you: Why is it only the set of all _humans_? If I could have found myself born in prehistory, could I have found myself born as another member of the genus _Homo_? If not, why not?
And if I could have found myself born as a Homo habilis, say, could I have been born as some other mammalian ancestor (yes I may not be conscious in that case, so unable to ponder the doomsday argument, but that’s irrelevant to the probabilities).
Does the chance of me being born as _any_ individual of any species factor in, or is a line drawn somewhere?
> [@](#):
>
> No, they’d completely correctly conclude that the likelihood is low that so many humans would ever exist; but as you say, unlikely things happen.
What use is an argument that we know must give incorrect answers at least some of the time?
> [@](#):
>
> But that’s exactly the sort of reasoning that leads to people thinking the simulation hypothesis is worthwhile at all—if the simulation of minds is possible, then we’re far more likely to be simulated minds, than real ones, because the number of simulated minds ought to vastly outstrip that of real ones.
Exactly, that’s what I said.
But what do you think about my point about that; that if we’re following the logic through, and concluding we’re in a simulation, we’re no longer making any claims or inferences about the real universe (apart from that it’s capable of making simulations). An argument posited against humans becoming type III completely fails to do so.
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### Author:  [@eburacum45](https://boards.straightdope.com/u/eburacum45)
#### Post date: [May 31, 2020, 8:38am UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/178 "2020-05-31T08:38:00Z")
> [@Larry\_Borgia](#):
>
> Yes I am flatly stating it is a practical impossibility. There isn’t the energy or the material to make one. I will continue to hold this position until you or someone else can show me a blueprint.
Since I design Dyson Spheres for a hobby, I can show you dozens of blueprints. The least massive ones are only as massive as a large asteroid (the Dyson Statite concept, made of thin material suspended on sunlight).
You can make them more massive, of course, as a swarm; few of the swarm designs can intercept all of the emitted light, but since the luminosity of a Sun-like star is a billion times more than the entire solar energy cross-section of the Earth, I think we probably won’t need it all.
The most difficult design to make and maintain would be the solid shell that most people imagine when they think of a Dyson Sphere. Even disassembling all the planets in the Solar System would only make a Dyson Shell about 20 centimetres thick (the hydrogen and helium in the gas giants do not make a very good building material). If you want more matter you would need to extract it from the star itself. There are design problems with making a solid shell, which do have solutions I won’t bore you with.
The fact that we haven’t seen any Dyson statites, swarms, shells or rings must mean something, but so far we haven’t really looked hard enough to make a definitive statement.
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [May 31, 2020, 10:04am UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/179 "2020-05-31T10:04:11Z")
> [@Mijin](#):
>
> To me it’s a self-evidently silly argument; there is no cosmic waiting room where souls wait for which body they will quantum leap into, so no reason to think probability can be applied here.
Again, this is a misunderstanding. You’re not calculating the probability of being ‘sent into’ any given human incarnation; you’re calculating the probability of being right about where you are, so to speak.
Consider the case where there are 100 humans to ever live. Then consider any one of them thinking, ‘I am among the final 50% of humans to ever live’. They’re right if they are one of humans no. 51-100. That is, half of all humans would be right in thinking that, half would be wrong. Hence, the probability that any given human is right in thinking that way is 50%. The same goes for any other percentage you care to specify.
The ‘cosmic waiting room’ would be needed if you were to stipulate that there is some other probability than the above for being right about where you are. Then, there would have to be some kind of ‘selection law’ such that the probability of ‘you’ being incarnated in your current form is not just a function of the total number of humans, but of whatever selection principle is at work. Say there’s some law that specifies, for each human essence, the human vessel in which it is incarnated: then, the probability of you being born as the particular being you are, in every case, would be 100%.
Absent any such influence, the probability of saying ‘I am among the final 95% of humans’ and being right is 95%, because 95% of all humans are within the final 95% of all humans, and hence, would be right in holding to that. Really—it’s just counting.
> [@](#):
>
> But let me try another argument to convince you: Why is it only the set of all _humans_?
It’s not, of course; it is the set of all minds that could ask this question. If that includes, say, Neanderthals, then the argument’s conclusion is borne out by observation: as Neanderthals form a small sliver of all such minds, you ought to expect not to be a Neanderthal. You’re not (best as I can tell), and hence, that conclusion comes out right.
> [@](#):
>
> And if I could have found myself born as a Homo habilis, say, could I have been born as some other mammalian ancestor (yes I may not be conscious in that case, so unable to ponder the doomsday argument, but that’s irrelevant to the probabilities).
It’s not. Again, it’s best to think about the probability in question as the probability for ‘being a mind correctly estimating the set of minds it is a part of’. So the probability of being right in considering oneself among the final 50% of humans is exactly 50%.
> [@](#):
>
> What use is an argument that we know must give incorrect answers at least some of the time?
Such arguments are tremendously useful, of course. Any scientific study with a statistical component—any correlational studies, all medical or psychological studies, and many more—are of just this form. As are all game theoretical arguments, all estimates, every experiment with nonzero error bars, and many, many others. Whenever you look at any study with a p-value greater than zero, that p-value tells you how often you’d expect studies of this kind to give a false effect. Whenever you, say, test for a disease with a test having a known false positive or negative rate, you know how often you should expect the result to be false; when you know the incidence of that disease in the general population, you also know how likely the outcome is correct in your particular case.
> [@](#):
>
> But what do you think about my point about that; that if we’re following the logic through, and concluding we’re in a simulation, we’re no longer making any claims or inferences about the real universe (apart from that it’s capable of making simulations). An argument posited against humans becoming type III completely fails to do so.
I don’t see a distinction at all—we’re talking about minds to ever exist, whether in ‘real’ or ‘virtual’ universes. In fact, I think this is a distinction without a difference—whether the fundamental ontology of the universe is quantum fields or bits and bytes doesn’t actually matter for the universe, and the minds therein, as such.
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### Author:  [@septimus](https://boards.straightdope.com/u/septimus)
#### Post date: [May 31, 2020, 12:01pm UTC](https://boards.straightdope.com/t/is-the-fermi-paradox-becoming-more-acute/759574/180 "2020-05-31T12:01:36Z")
A civilization that sends billions of probes to other solar systems need not be intent on “conquest” per se. They might just be tourists, preparing a scrapbook to document interesting worlds. (Of course they would “mine” systems for the raw materials needed to construct more probes and other vessels. But they might have an ethical code to minimize disruption on worlds with advanced life.)
Can experts help me understand how these interstellar vessels would communicate with each other at near-light speed? Are directed laser beams the best approach (known to us at present)? How much power would it take to send a signal five light-years, or would it be infeasible without many repeater nodes along the route?
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