What are Ancestor Simulations and are we living in one

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This episode is brought to you by Brilliant! There’s a lot of discussion about if we are   real or merely in someone’s simulation  or dream, but what if we are real,   we just died centuries ago and keep  getting resurrected over and over again? Some call it the Simulation Argument,  some the Simulation Hypothesis,   and it’s a concept that in many ways predates  the computer age, but fundamentally comes down   to asking if we are living in a dream or computer  program, or fundamentally, if we are real.  Today, we will be looking at the specific case  of Ancestor Simulations, and indeed this is the   actual case for computer simulation discussion but  that tends to get left out of most discussions,   and in my opinion is a lot of why the topic is  both controversial and confusing to folks. I   want to start from the outset, since this topic  tends to draw some reckless talk and clickbait,   that I’m not going to prove to you today  that you are or are not in a simulation,   it is not something that you can easily prove  either way, and it is a real possibility   but nothing approaching a certainty or  likelihood that we’re in a simulation.   We will want to explain why today and also how  concepts like ancestor simulations are distinct   from classic notions of us living in a dream. The basic notion is hard to credit to anyone and  

indeed the idea we’re in a dream, probably dates  back to the dawn of humanity – or to whenever   the dreamer started dreaming. However it  was philosopher Nick Bostrom who developed   the formal argument a generation back, and it is  very specific to the case of Ancestor Simulations,   we’ll detail those more in a bit but  summary form is: Its where a civilization,   centuries ahead of us currently, likes  to runs simulations of its actual past,   or also very parallel ‘what if’ scenarios. That’s  very important to the concept as we’ll see.  Now by default, folks discussing Simulation  Argument, tend to just mean any simulation or   virtual world with people like ourselves  in them, but that does not fit the case.   We’re not really talking about if some person  or persons with access to vast computing power,   built tons of virtual universes below  them, of any traits and style they wanted,   and that case is really no different than  notions such as black hole mini-universes:   the idea that every time a black hole forms,  a new universe is big-banging out somewhere.  

These aren’t really discussing that you might be  in a fake Universe, in the sense of mimicking a   prior period of your own civilization, it's simply  saying that Universes can spawn children, by   nature or intelligent action, assembled underneath  high levels like a family tree, and the flavor is   more like a child-universe or sub-verse rather  than more aquarium-reality flavor that simulated   civilizations often seem to have, existing for  entertainment or research, living in a fishbowl.  There are other reasons you might do an ancestor  simulation besides those, but there’s an almost   unlimited number of reasons to make sub-verses  and these in generic format can’t tell you much   about the simulator. See, if I simulate the 19th  Century Earth, those living inside that simulation   speculating on if they’re real, will be  in a Universe with the same physical laws   and culture of our 19th century, and from which  our 21st century existence is derived. So they can  

usefully speculate about us and our motives. On  the other hand a person might simulate a Universe   utterly different in physics and geometry from our  own, and by that same reasoning, if our universe   is simulated, but not an ancestor simulation,  the simulators might not be using ‘computers’,   because they might come from a Universe which  has no atoms, where gravity is a billion times   stronger, where there’s 5-dimensions and  neutrinos mass as much as neutron stars,   and where concepts like entropy and  thermodynamic limits simply don’t apply.   Indeed even the laws of mathematics might differ. Now, mind you, some rough sketch of a fantasy   world on a piece of paper can be argued to be a  simulated universe itself, and those can often   grow in complexity, like Tolkien’s Middle  Earth or countless other fictional settings,   and those details in those fictional settings  actually do tell us a lot about humanity and   the author and the world they live in, but mostly  only make sense as clues when we already know the   details of that Universe. Tolkien’s Middle Earth,  which could be argued to be an ancestor simulation   since it’s supposed to be set in the distant past  of our own world, implies a lot of normal physics,   gravity and chemistry and so on, but rarely gives  any detail. At no point in the story did Frodo or   Bilbo announce how fast an object falls in terms  of local gravity or that they’re breathing oxygen.  

And indeed, that setting, like so many fictional  ones, has some hard breaks with science.   Middle Earth has had periods without a Sun,  in favor of glowing trees or gemstones,   or where it was Flat, before Numenor sank. Now these worlds are not simulated to the degree   requiring consciousness by the characters in them,  presumably, and ours, if it is simulated, does.   It is possible that we’re really simple compared  to the unfathomable supermind that built our   simulation, but nonetheless, we’re conscious,  or at least I am, and you presumably can be   confident you are too. Cogito, Ergo Sum, I think  therefore I am, as Descartes put it, though the  

assertion is not that we are real, merely that you  cannot usefully doubt your own existence, since   someone would have to be doing that doubting. So the Simulation Argument starts with saying   that, either it is possible to simulate a previous  age of your world, complete with simulated minds   that could think they were real, or it is  not, then, it says that if it is possible,   we must ask if future civilizations  would do it or not, and if so, how often?  The basic reasoning that folks often cite for  giving a probability of our real-ness or not,   is to use the Principle of Indifference. This is  the philosophical or mathematical notion that in   the absence of any evidence pointing one way  or another, you should assume your various   solutions or outcomes are equally likely. As  a quick example, if you run along a corridor,   chasing someone and lose sight of them, then come  to a room at the end with three closed doors,   you have to initially assume each option  is equally likely as the way they fled,   a 1 in 3 or 33.33% chance the person you’re  following took a particular door. If it was  

actually three thousand people running  down that corridor - at different times,   so that you had no reason to think any of them  were influencing each other’s choices - you’d be   assuming about a thousand ran through each door. Now, in practice, you can often find some   evidence; footprints, fingerprints or wear  and tear on the door knobs would be examples.   So too, we could speculate that right-handed folk  might be more likely to use the right-hand door,   or that they are painted red, green, and blue  and folks tended to be more likely to go through   the green door and least likely to go through  the red. Also we have to consider that we’re   focusing on the doors to exclusion, and ignoring  options like them having fled through an air duct,   hidden in a corner or hanging from the ceiling,  or possessed an unexpected ability, like turning   invisible or teleporting. And especially when  dealing with intelligent actors, you need to   contemplate them intentionally acting atypically. Nonetheless, that’s the idea behind the principle  

of indifference, and it’s a solid one, when  presented with 2 or more plausible outcomes   and without any real evidence indicating which  is more or less likely, we assume they are all   about the same until we can demonstrate otherwise,  and emphasis on this being a working assumption.   In a moment, I’ll declare that the odds  of you living in an ancestor simulation   are 33% and that is going to be based on the  principle of indifference. That number is not   likely to be the real odds, merely that those are  the hypothetical odds given to make this point.  

Indeed, technically, there are no odds, you either  do or do not exist in one, but where we’re trying   to get the odds, the fact that something  can be assumed to be one-in-three because   we simply have no evidence to the contrary,  is not a compelling argument of any kind.  I felt like that needed saying upfront, because  a lot of folks get some existential terror at the   idea of being in a simulation and folks often  talk about what the odds are as though we had   actual evidence rather than a probabilistic  argument. In and of itself the basic argument   for the simulation hypothesis is the same  as saying there’s a 50/50 chance someone I   meet is a serial killer, because people  either are or are not a serial killer,   thus, by Principle of Indifference, anyone I  meet has that 50% odds. That’s not the case,  

and we have data indicating how likely people  are to be Serial Killers and it's pretty rare.   We could also set that up as saying we found a  dead body and assumed it was either natural causes   or murder, and if the latter, either it was done  by someone who rarely murders people, or who does   it a lot, three options: natural causes, murder  by an amateur, or serial killer. In the absence   of any other evidence we just say it’s 1 in 3,  that’s the idea. Then we try to find more evidence   to adjust those numbers to better represent  reality, it's just kinda hard to do that when   the question in mind is if we live in reality. Now for the Simulation Argument, there are three   propositions, and those are that, it either is  or is not possible - in a particular universe,   with either the same, or different natural laws -  to make ancestor simulations, and that if it is,   civilizations either choose not to make  ancestor simulations or they do and do it a lot.  

Such being the case, it can be assumed that  there’s a 1 in 3 chance that the third option   is true, that ancestor simulations are possible  and that civilizations opt to do them a lot;   that once folks have the technology to emulate a  mind or reality, they often replicate some period   of their past, including various people who aren’t  alive anymore – their ancestors, whom they are now   simulating, and who believe they are real. The follow-up, is the idea that if we’re assuming   proposition 3 is true, that civilizations who can  simulate, do so frequently, then that means that   actual civilization did once experience the year  2022, when this video airs, but they have also   simulated many times, maybe millions of times.  The folks in those simulations, who are fully   emulated human minds, do not know they are in a  fake copy or ‘what if’ scenario of the year 2022,   like the one with where that war or market crash  or disease variant did end up happening as opposed   to being narrowly avoided. Or the simulation  where nuclear war didn’t happen, for those who   want to go vacation in their innocent youth,  before the bombs landed and all the survivors   were techno-barbarian cyborg mutants. And I do not know if I’m in the original   or a copy, and if there’s 99 copies and 1  original, there’s only a 1% I’m in it. So in that  

case, there’d be a 1 in 3, or 33.33% chance I was  in a reality where ancestor simulation was common,   and a 99% chance I was in such a sim,  there’s an even 33% chance I’m a sim.  Now this is not wrong, the logic applied is  entirely proper and functional. It doesn’t  

mean it's right either, and as an example, we  can add more options by not being so binary.   For instance, we could say that simulation  might be physically possible but civilizations   capable of doing it may be automatically prone to  self-obliteration through some crazy AI running   amok. Or that it's possible, but almost always a  very brief phase leading to a few dozen simulated   universes that are few in number or occupants,  and get banned or unpopular almost right away.   Either makes us have a fourth option and changes  the reasoning, by Principle of Indifference,   to 25%. This doesn’t somehow mean you’re actually  more or less likely to be real and not a sim.  What’s different about an ancestor  simulation idea over classic: ‘life is   a dream’ concepts? Or is there no difference? Well, there is a real difference, and I think   folks miss that when discussing Bostrom’s concept,  by assuming it’s merely a modern version of   dream-existence. It is not computers that make the  simulation argument different either, not exactly.   That’s really just a substrate, the specific way  the new reality is made, and when we’re talking   about simulated realities in general, you can  use the words Programmer and God interchangeably.  

A Universe dreamed up by deity, like with Brahma  of Hinduism, who sleeps and dreams our Universe,   probably does not have a brain made of neurons,  our brain’s substrate, anymore than silicon   wafer chips, a computer or AI’s substrate. Which  might also be made of other materials and in a   simulating universe might be made of materials  that don’t even exist in our simulated or dreamed   reality. Again, the computer and programmer versus  dreamer or deity part, is pretty semantic here.  Instead, what’s relevant is the ancestor  simulation notion itself, which speaks to   motivation. A little bit ago we talked about  how by Principle of Indifference there’s a 1   in 3 chance we’re in a simulated reality and  the other two thirds were a Universe where   simulating minds of our complexity, is simply not  possible or was possible, but simply was not done.  The problem though, is that that first clause  is essentially a throw-away in modern context.   We’ll be able to build computers big  enough to emulate a human mind and more.  

We probably already have supercomputers powerful  enough and now it's more a coding issue,   and a recording one, if we care about specific  individuals. We could raise notions like:   if a human – like you or I – could be emulated  on a computer without losing some unknown mystic   quality, but this then merely rephrases the  idea that Heaven or Hell or the Fey Realm,   or other such places are a different layer of  reality, maybe a superior or older one even,   but not implying the layer we’re in  is somehow fake and us along with it.  Though, for my own part, I don’t really see the  difference between a person born in an ancestor   simulation and another who was not, in terms  of basic personhood. Obviously, if one of them   did have a soul and the other did not, that’s a  decent basis to challenge, if that soulless person   is indeed a true person. However, since souls seem  to be rather evasive at detection or description   at the moment, it is not a topic we can usefully  speak about, in a scientific context. This is why  

I often say, on this topic, whether or not we  are in a simulation, and thus real or unreal,   is the wrong question to ask, the better one is  if it actually matters. I am real, I am a person,   show me I am in a simulation and I’ll just say the  definition some use for reality needs adjusted.  Nonetheless, that first point, that  we can almost take for granted that   simulating minds is possible, would raise  our odds of being in a simulation to 50/50,   since it’s saying we can and thus the question  is just if we do or do not, in a few centuries   or so when we get the technology perfected,  which again might have been in our own past.  Now we need another caveat, because emulating  a mind to the point you and I have, is way   beyond what is likely to be needed for realistic  human portrayals in entertainment or education   simulations. We have this leftover  perspective from early science fiction days,   that anything able to interact at the human  level, needs something near human intelligence and   consciousness. This is why we get humanoid robot  butlers in books and films who can run a vacuum   and wash dishes and have a heart to heart talk  with people, and in practice we get a chatbot,   a robot vacuum cleaner, and smart dishwasher,  not some thing which might debatably be a person. 

The simple reality is that if you want to go  live in a virtual reality, killing orcs or   rescuing damsels-in-distress from fire breathing  dragons, none of them really need to be running a   conscious mind, of human level, all the time – or  probably ever – but certainly not when off screen.   It’s like needing to be able to read a book for  five minutes and thus building an entire sun to   read by, that lives for a billion years and shines  over a billion square kilometers of real estate.   It’s just pointless waste, and I think it's just  because folks aren’t thinking about how wasteful   it really is that makes them assume a powerful and  wealthy future civilization might do it anyway. 

But you don’t. You live in a Universe where  entropy is real and energy is limited, because   we’re talking about an ancestor simulation,  so they more or less match our own universe   up above in their ‘real’ one. You don’t build a  mountain range to shield yourself from a breeze,   even if you can. You don’t simulate 8 billion  minds as full people unless you need to,  

because it's probably millions of times the  effort an otherwise practically identical,   non-sentient simulation would need. And all  such simulations are about cutting corners,   you don’t simulate individual molecules  if you don’t have to, for instance.  Thus, we can make a pretty good argument  why folks in the future might be able to   do ancestor simulations but do not. And this to  me is the critical bit. I don’t think it is a  

50/50 proposition that we do live in a reality  where such simulations are possible, but either   do them a lot or not at all. I just don’t see  any logical reason why “We” would ever bother.   And mind you, this is not some casual exercise,  it is like saying I can’t see any reason why   we would bother to build an ICBM with a nuclear  warhead, capable of blowing up the entire planet,   because it would be insanely expensive to do  and before you got up to even a millionth of   the needed strength, it would already be able  to sterilize all life on the planet, which   lives in a thin little layer on its surface. And  critically, why would you launch that on an ICBM?   It’s the same concept, simulating 8 billion people  is that kind of pointless overkill. I want to   blow up the entire planet, even its unoffending  mantle and core, just to get those lava people,   and I want to do this by sticking it on a missile  with just enough fuel to fly from one side of the   planet to another. Even though detonating it  anywhere near the planet does the same thing,   making the rocket silly. How often  does this device really get built?   Probably as often as a first person shooter  bothers simulating the rifling inside a gun   barrel the player can’t see and does it  all the way down to the atomic level. 

Now that’s an important note too. We’ll be  discussing briefly, various things around   us that folks take as proof or evidence for or  against us being in a simulation, and some of   these are just bad arguments. A common one is that  it just wouldn’t be possible to simulate every   atom in a planet, let alone a Universe, and it  ignores that there’s no reason why anyone would.   Unless they literally had infinite mind and  power, in which case we’re in a pretty classic   creator-deity situation and I don’t think calling  their creation ‘fake’ is likely to be meaningful   or accurate. Where they are finite, they need  to avoid waste, or wasteful excess simulation.  If I am in a virtual reality designed for scenic  walks I do not need the jogger passing me in   the other direction to have an actual brain,  nor the deer that ran across the path to have   individually simulated gut bacteria. What I  need is a program that ramps up the effective   resolution of reality when I’m in proximity  and interaction. A program switches on to make  

things up for the jogger to say if I stop them,  or for under a microscope, if I decide to shoot   the deer and inspect its stomach for bacteria. Now, some would say that this is where Quantum   Mechanics gives the game away, because the  Uncertainty Principle is a sort of minimum   resolution or pixelation to reality, albeit with  complimentary variables. There’s no minimum size   really, maybe a planck length, but rather there’s  a minimum combination of position and momentum,   or energy and time, that we can know  simultaneously. Still really just a type of pixel.   And because of that there’s no way to exactly  predict what will happen or what did happen,   and thus you can’t model every single atom at the  present to show how it is inconsistent with the   recorded past or future and thus a made up fake. And that’s true enough, but not necessary. Folks   tend to forget that a simulated person is not some  brain in a jar or person in a battery-tank from   the Matrix. The programmer can leave triggers  in your head to flag them if you think reality   is unreal and delete the inconsistency or even  just tell you it wasn’t. It’s the same as if  

an omnipotent God didn’t want you to be certain  it existed, it is all powerful and all-seeing,   so if you suddenly became certain, it knows, and  can just tweak it so you didn’t feel that way   anymore. A lot of the little tells folks see  about simulated reality and us being in one,   or not in one, benefit from being  viewed from that divine perspective   rather than assuming there was some programmer who  was maybe just a bit smarter than you or I. More   likely it's some technological singularity who  stands above us mentally, the way we do an ant.  You’re not outsmarting them or it, and seeing  some clue they didn’t realize was there,   because even if you did see something they somehow  did not, they can literally hit the pause button,   go back to a previous save state, and fix  either that problem or your ability to see it,   and remove that bug for future folks. This is  a simulated reality, and a simulated person,   if you’re in one, it’s not just that they can  affect your surroundings, by, for instance,   having a 900 pound gorilla appear in front of you,  it’s that they could make that happen while also   making it so that you didn’t believe it was there,  even while it was tearing up the scenery and those   around you were saying ‘wow, what a big gorilla!’ The same applies for something like the size   of the Universe. Folks often argue that a  Universe so big couldn’t be meant to be empty,  

thus, either we should colonize it, or other life  is there. Many folks interpret this as proof of   a simulation or a more classic supernatural  creator, many view it as the exact opposite,   proof there isn’t. It might actually be either  but merely as that data currently presents itself,   it’s not a compelling argument of any kind, folks  are engaging in that bad habit of interpreting   evidence to support their view rather than lining  it up with falsifiability. Scientific and logical   falsifiability is where you hypothesize that  something, if true, would support your theory and   if false, falsify it. Something you do not know  the answer to yet. Then you go find out which it   is; instead, with simulation argument, folks tend  to try to take any new bit and squeeze it into   their belief on the topic. This is hardly unique  to Simulation Argument of course, and we all   tend to be guilty of that occasionally, but it  comes down to that Anthropic Principle problem,   which the Simulation Argument is used to explain. The Anthropic Principle is the opposite of the  

Mediocrity Principle, and you might not have heard  of either, but you engage in both regularly and   should. Both are approaches to looking at reality  when you have little evidence or means of getting   more information. Mediocrity Principle is the  assumption that if I land on a planet and the   first few folks I meet are wearing green, that I  should assume that’s fairly normal and to them,   a mediocre example of clothing colors. Anthropic  principle is where we assume that, me being there,  

is some factor in their choice to wear green, like  if green is their color for meeting honored guests   from afar. Neither is right or wrong, indeed  they are both usually wrong as you get more data,   but they’re both good approaches to encountering  new strange things when you can’t get more info.   The reason everyone around you is wearing hospital  scrubs is because you banged your head and your   friends took you to the hospital, not because most  people wear scrubs. However, you would already   know this or easily be able to ask a few questions  and make a few observations and figure it out,   so it's not great for demonstrating  the concept of the Anthropic Principle.  To demonstrate the Anthropic Principle,  it saves time if the examples don’t permit   the person you’re discussing it with to say  things like “Well I’d look it up online” or   “I’d do a few tests”, so we use three popular  examples. One is a Fine-Tuned Universe,  

the apparently freakishly slim odds the physical  constants in our Universe would allow life,   and since we can’t currently look outside  our Universe to see if there are others,   we have no known way of proving if our  Universe is a mediocre example of universes,   most of which have life, or a freak case that  we can only see has life because universes   without life don’t have anyone to look at  them and notice they’re the regular kind.  The Next is the Doomsday argument, see that  episode for details, but it tries to argue that   you’re more likely to be a middle-child of human  history, than one of the eldest, since there are   going to be way more middle children, and thus  human history is nearly over – and of course you   can’t present evidence for or against that sort  of assertion. Simulation Argument is the same,   there is currently no known way to prove  or disprove it from the evidence on hand.  I want to emphasize that, because while  all three concepts, Fine-Tuned Universe,   Doomsday, and Simulation Argument, have  a lot of serious and grim discussion,   they are academically really boring and are  mostly valuable for preventing folks from   stopping you in the middle of the discussion  to point out a way to prove it right or wrong.   Other examples of the Anthropic Principle,  or Mediocrity Principle, tend to have really   obvious and easy ways to gather evidence. If a  tree falls in the woods, does it make a noise?  

Yes, at least under the current definition of  noise, and if the point you’re trying to make   is that, events which are not seen or observed and  do not affect others, maybe doesn’t truly matter,   then you’ll save headaches by setting the event  in a different reality where we cannot see or   feel it falling. When it comes to Simulation  Theory though, we don’t need to bother simulating   every tree falling, including ones that fell  in times and places no person will ever see.  And you probably don’t actually care if your  fossil record that you made up, is a perfect   match, so you don’t need to go through a big bang  and run every planet in the Universe forward to   the present to simulate modern times. You don’t  really need a catalog of every tree that ever   existed on Earth because it’s not possible for us  to run about 350 million light years from Earth,   faster than light and build a mega telescope to  observe the evolution of the first trees and see   if they match locations in our fossil record.  There’s no FTL – and indeed this is another  

thing you’d want to avoid in a simulated reality,  superluminal cause and effect – but if there were,   you could still just make stuff up. It’s not that  someone might catch that a few positions were off,   you can have a whole room of scientists  staring at flawed data on a table,   all nodding and agreeing it was correct.  They’re sims and you’re the programmer,   you could set the table on fire and tell  them they were looking at totally accurate   data with no anomalies even while the fire  alarm was going off for no apparent reason   and not worth checking on. You control reality,  including the people in it and their own minds.  It's a little discouraging to think you could  be someone’s puppet like that, and have no way   of beating the system or red-pilling out of the  Matrix, but that’s basically how that should work   and I think folks try to slip around it. Now, onto why we probably are not in one.  

First, there might not be any ‘we’ involved.  It might just be you, but that’s not really an   ancestor simulation and thus isn’t part of the  argument. Let’s assume in the next few decades,   we get computers that are, say, orders of  magnitude more powerful and get our brain scanners   and deep-learning AI upgraded similarly. That  should permit a capacity to scan a brain quickly   and detailed enough to either read it or emulate  it, same difference in this context. Whether I’m  

an uploaded mind 30 years from now or a human with  my brain being real-time scanned and a simulation   directly fed back to my nerves, there’s a strong  implication there that I’m functionally immortal,   and that could happen in our lifetime. Such being the case, it’s trivial to come   up with reasons why you or I would choose to  be in an ancestor simulation and even submit   to some flat-out brainwashing to help us ignore  any inconsistencies. And our time is not mediocre,   this, the 21st century, is probably the last one  people will exist in, during which the technology   on hand doesn’t make faking reality so obviously  doable that people don’t either worry about it   constantly or have to live in denial to stay  sane. Folks worried about it in the past too,  

when dreaming, and good books or hallucinatory  drugs were your only routes to fake worlds.   So just imagine what it will be like as  these technologies come into real use.  So it is plausible that this is the most simulated  era, that while folks go visit history sims or   fantasy settings, the one they actually lived  in originally is the one we replicate the most.   It’s hard to imagine simulating a whole world  of fake but total people for one person’s   entertainment, but not so hard to imagine a thin  resolution world for one person to experience only   the bits really in proximity to them, or millions  of us sharing an ancestor sim with a few billion   sub-sentient folks to fill up the landscape. It is kind of hard to imagine us, as we are now,   if we were still that way in a future able  to do this simulating, not choosing to do   it fairly often. Go relive a period of  our life, maybe do it a bit differently,  

after all, we all play that ‘what if’ game  occasionally and I daresay we do ‘what if’   for our own life more often than daydreaming  fantasy and fictional life. It would seem then,   to say that our odds of being in some sort of  simulation, even if it is as the voluntary client,   who paid not to remember they were in their own  simulation for a while, is actually very high.  Let us say you were born in the real 21st  century but it is now the year one million AD,   and you happen to be in a simulation of the  21st century at the moment but have had a bit   of dream-tech applied so that you forget you’re  here as a visitor. Every few centuries, you go   spend a few decades back in the good old simple  days, maybe raise another couple kids to join you   up in the real world, who will have the advantage  of growing up in the fairly civilized 21st century   but still endure some hardship and not be spoiled  or inhuman by being born in the distant present.   Or maybe you are such a child and your parents  are the ones from 1 million AD and it’s been a   family tradition for 998 centuries to raise new  kids in the simulations of the glorious old 21st.  That then, is probably the final note. Some folks  say ancestor simulations probably just wouldn’t  

get done, not because we couldn’t or wouldn’t,  but because the civilizations able to do so   would not. Maybe because such civilizations always  have a machine rebellion and unlike in the Matrix,   that machine is smart enough to know that humans  don’t make good power production devices and thus   don’t keep us around in some fantasy history.  Maybe because all that ability to emulate and   copy minds results in them being post-humans with  less emotional desire to revisit the past that   way. It’s arguably inefficient and even mentally  unhealthy to want to live in a fake world that way   and such masters of the mind, able to create  believable fake worlds, and believable   fake minds, probably are also masters at  detecting mental illness and treating it. 

Their reality might just not have folks who would  either want to live in the past that way or would   be so crazed, wasteful, or immoral as to make  simulated humans with real minds and feelings,   like some disposable lab rat. They may not need  to raise their kids in some fake idealized past   to keep them from being spoiled, they might just  be good at not raising spoiled brats or hedonists.   Or they might all be extreme hedonists in  which case, I don’t know about you, but my own   reality and life doesn’t seem like a hedonistic  adventure. And I really quite enjoy life too.  I think that’s what we’ll close on then. As I  said at the beginning we weren’t going to be  

able to prove or disprove if we were or weren’t  in an ancestor simulation, let alone other types   of simulations, sub-verses or dreams. You could be  some randomly assembled Boltzmann Brain, existing   in total sensory deprivation in some universe with  utterly different physical laws than ours, slowly   going insane and hallucinating a whole universe,  our universe, or you and I might both be sentient   hallucinations of such a mind. Again, I’m  not sure if just being in your own personal   past simulation counts as an ancestor simulation  either, but you could be in one of those. 

In the end though, I don’t find it very likely.  Not because I can’t see myself doing it, but   because I can see myself telling others it is a  bad idea, a morally iffy thing in some cases and a   waste of time in others. I don’t think I’d vote to  approve funding for SimEarth2022 or let it slide   without active complaint if someone was simulating  real minds in some personal paradise of theirs,   where they could do to them what they pleased. And  I don’t really think a smarter and wiser version   of me would be more okay with such things. I  suspect that’s true of most folks, especially  

most folks who live in a post-scarcity future  world with life extension and mind augmentation.   We would expect them to be older, wiser, and  smarter on average than us, and I tend to assume   that means more ethical than us on average too. And of course to me, noted techno-optimist,   who tends not to be cynical about people, that  equates to Scenario 2: Ancestor Simulation   is possible, but just doesn’t get done as it’s  impractical and immoral, thus the odds of us   being in one is slim. Too much effort just  to achieve a goal that might get you lynched.   If you’re of the opinion that folks couldn’t wait  to take a deep dive into a reality they ruled   and had real emulated minds in it, and this would  happen many times, even if others tried to stop   it, then things look more glum. Such being the  case, it is very easy to believe, folks like   that would particularly love reliving their youth  to prove wrong or punish those who scorned them,   making ancestor simulations common, because they  really want those people they’re interacting with   to be real, with feeling, including pain  and regret, not just some advanced chatbot.  

Then you pretty much get stuck with Scenario  3: Simulation is possible, it happens a lot,   and statistically, you are probably in one. Needless to say, I think I prefer Scenario 2’s   assumptions be true over Scenario 3, but that’s  mostly what it comes down to. If you think a   future humanity is one that would eagerly abuse  such ancestor simulations or be indifferent to   preventing them being abused, then it’s not really  a question, if there’s a high probability this is   all really a dream, it’s more about worrying if  someone’s dream is putting you in a nightmare.

So a key point of today’s episode is not just  that it is very hard to emulate a human mind,   let alone billions of them, but that it is just  orders of magnitude more difficult than creating   passable simulations. The more we learn about the  mind and neural networks, the more we realize how   hard they are to build, and how often something  vastly simpler and easier would get the job done.   Neural networks are one of the most fascinating  new areas of computer science, and if you want   to learn more about them, Brilliant’s interactive  courses on Neural Networks and Computer Science   Fundamentals can help you on that journey to  better understanding our minds and machines. 

One of the things we’ve learned about our minds as  we’ve come to better understand neuroscience and   neural networks is better learning and critical  to that is interactivity, hands-on learning is   hands-down the best kind, and that is something  Brilliant builds into all their courses,   and constantly seeks to improve. To make it easier  for anyone to learn Math, Science, and Computer   Science, be it the basics or advanced materials. For instance, Brilliant’s Computer Science   Fundamentals course takes you through the basics  of computation with their trademark interactivity,   even showing how decisions get made. But  picking Brilliant as a learning partner   is an easy decision, especially  as you can try it out for free. 

With Brilliant, you can learn at your own pace,  learn on the go, and learn something new. To get   started for free, visit brilliant.org/IsaacArthur  or click on the link in the description,   and the first 200 people will get 20% off  Brilliant's annual premium subscription. So next week we will be having our 2-hour  episode The Megastructure Compendium,   our expanded and improved version of our original  episode on Megastructures that started the show   almost 8 years ago. Back then I had done the  episode in large part because I felt so many   scifi authors missed the chance to use these  immense and wonderful artifacts in stories,   and I’m very glad to say a lot of authors  have used them more in more in recent years,   many of them fans of our show. I wanted to give  a shoutout to the Father and Son writing team   Patrick and Blake Seaman on their  new series, starting with book 1,   Accipiter War, where a modern day town and  a military base find themselves mysteriously   awakening inside a giant McKendree Cylinder. I’m  about 100 pages in and I love the book thus far  

and love knowing our show helped inspire it,  definitely worth checking out. Also really glad   to see the McKendree Cylinder, the big-big brother  of the O’Neill Cylinder, getting to be a setting.  Again next week we’ve got that Megastructure  Compendium coming up where we will be going over   around a hundred megastructure types and hopefully  they’ll help inspire some great new stories too,   science and scifi have a long history of positive  feedback with each other. Speaking of which,   the weekend after that we’ll be having our monthly  scifi Sunday episode, on June 12th, where we’ll   look at the Silurian Hypothesis, the concept  that some ancient civilization like intelligent   dinosaurs might have once dwelt on Earth long ago.  We will also ask what would remain of humanity’s   accomplishments millions of years from now if  we suddenly died off. And two weeks from now,   we’ll be looking at the concept of Interstellar  Probes, where we’ll begin our two-part story of   traveling to an anomalous system to investigate  it, concluding with Life as a Planetary Explorer. 

Now if you want alerts when those episodes are  coming out, make sure to subscribe to the Channel   and hit the notification bell, and if you enjoyed  this episode, please hit the like button, share   it with others, and leave a comment below. You can  also join in the conversation on any of our social   media forums, find our audio-only versions of the  show, or donate to help support future episodes,   and all those options and more are listed  in the links in the episode description.  Until next time, thanks for  watching, and have a great week!

2022-06-04

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