Are You Living in a Computer Simulation?
TL;DR: Either humanity is screwed, or super-advanced civilizations don’t care about simulating their past, or we’re almost certainly living in a computer simulation right now. Pick your favorite existential crisis!
What We’re Talking About Here
Okay, so Nick Bostrom, a philosopher at Oxford, wrote this paper that basically says: “Hey, at least one of these three things is definitely true, and all of them are kind of terrifying.”
But before we get to the terrifying part, let’s talk about video games for a second.
The Basic Idea (Or: Why The Sims Is More Profound Than You Thought)
Imagine you’re playing The Sims in the year 2085. Except your computer is so absurdly powerful that the Sims don’t know they’re Sims. They think they’re real. They have conscious experiences, hopes, dreams, existential crises about whether they’re living in a simulation (lol).
Now, if you can run one of these simulations, you can probably run a million of them. Or a billion. So now you’ve got a situation where there’s one “real” world and billions of simulated worlds, each filled with conscious beings who think they’re real.
Here’s the uncomfortable math: If there are billions of simulated conscious beings and only a handful of “real” ones, and you’re a conscious being... well, what are the odds you’re one of the real ones?
This is basically Bostrom’s argument, except with more philosophy and equations.
The Three Possibilities (Pick Your Poison)
Bostrom says at least ONE of these must be true:
Option 1: We’re Probably Going to Die Before We Get That Advanced
This is the “Great Filter” option. Something prevents civilizations from reaching the “posthuman” stage where they have god-tier computers. Maybe it’s climate change, maybe it’s nuclear war, maybe it’s some technology we invent that accidentally kills everyone (Bostrom really likes the “murderous self-replicating nanobots” scenario).
The depressing part: If most civilizations don’t make it to the advanced stage, and we have no reason to think we’re special... we’re probably not making it either.
Vibe: 😰
Option 2: Advanced Civilizations Just... Don’t Want to Run Simulations
Maybe every advanced civilization reaches a point where they’re like, “You know what? Running ancestor simulations of our primitive past is actually kind of boring/immoral/pointless.”
For this to work, it can’t just be some advanced civilizations that lose interest. It has to be basically all of them. Because if even a small percentage of advanced civilizations run simulations, and each one runs billions of simulations, the math still works out that most conscious beings are simulated.
Why might they not want to run simulations?
Ethical reasons: “Wait, these simulated people can suffer. That’s kind of messed up.”
They’ve moved beyond it: “Why would I run a simulation of 21st-century humans when I can just directly stimulate my pleasure centers and experience infinite bliss?”
It’s scientifically useless: “We’re so smart now that watching our ancestors argue on social media teaches us nothing.”
Vibe: 🤷
Option 3: We’re Almost Certainly in a Simulation Right Now
If Options 1 and 2 are false—meaning civilizations do reach advanced stages AND they do run lots of simulations—then the math is pretty clear: most conscious beings exist in simulations.
And if most conscious beings exist in simulations, and you’re a conscious being with no special information about whether you’re simulated or not... you should probably bet that you’re in a simulation.
Vibe: 🤯
The Technical Stuff (Or: Can We Actually Build The Matrix?)
Bostrom spends a lot of time showing that this isn’t science fiction—it’s theoretically possible with technology that doesn’t violate any laws of physics.
How much computing power do you need to simulate a human brain?
Conservative estimate: About 10^14 to 10^17 operations per second
That sounds like a lot, but...
How much computing power could an advanced civilization have?
A computer the size of a planet: ~10^42 operations per second
That means a single planetary computer could run the entire mental history of humanity in less than a second using a tiny fraction of its processing power
What about simulating the environment? You don’t need to simulate the entire universe down to the quantum level. You just need to simulate what people experience:
Far-away galaxies? Low-resolution is fine.
The inside of the Earth? Skip it entirely.
What someone sees through a microscope? Render it on-demand, like a video game loading textures.
The simulation only needs to be detailed enough that nobody notices the glitches.
The Probability Argument (With Less Math)
Here’s Bostrom’s actual argument, simplified:
Let’s say:
f = fraction of civilizations that reach the posthuman stage
N̄ = average number of ancestor-simulations run by posthuman civilizations
H = average number of people who live before reaching posthumanity
The fraction of all observers living in simulations is:
fN̄ / (fN̄ + H)
Now, if civilizations reach posthumanity (f is not tiny) AND they run simulations (N̄ is huge), then this fraction is very close to 1.
Which means: almost everyone is in a simulation.
The Indifference Principle (Or: You’re Probably Not Special)
Bostrom uses what he calls a “bland indifference principle”:
If you know that X% of observers are in simulations, and you have no special information about whether you specifically are simulated, you should think there’s an X% chance you’re simulated.
This is like: If 99% of lottery tickets are losers, and you have a lottery ticket but no information about whether yours specifically is a winner, you should probably assume you’re going to lose.
Except instead of a lottery ticket, it’s your entire existence.
What If We’re Actually in a Simulation?
The good news: Most things stay basically the same. Physics still works the way you think it does (within the simulation). You should still make plans, brush your teeth, pay your taxes.
The weird news:
Our “posthuman” simulators would be essentially gods—they created our world, can monitor everything, can intervene, maybe even provide an “afterlife” by backing up our consciousness
There might be multiple levels of simulation (simulations within simulations)
Everyone at every level would have an incentive to behave morally, just in case they’re being watched by the level above
This creates a kind of universal ethics “from nowhere”
The bad news: They might turn off the simulation once it gets boring or too computationally expensive.
So... Which One Is It?
Bostrom basically says: “I don’t know, man. Seems like you should split your credence roughly evenly between all three.”
But here’s the kicker at the end: “Unless we are now living in a simulation, our descendants will almost certainly never run an ancestor-simulation.”
Why? Because if we’re NOT in a simulation, that means either:
We’re going to die out (Option 1), OR
We’re going to reach posthumanity but decide not to run simulations (Option 2)
The only way our descendants run lots of ancestor-simulations is if we’re already in one.
The Big Question
So here you are, reading this explanation on your device. Are you real? Are you a simulation being run by some teenage posthuman doing their homework? Is that posthuman also in a simulation?
Bostrom’s answer: At least one of the following is true:
We’re doomed
Advanced civilizations are weird in ways we can’t imagine
You’re in The Matrix right now
Sleep tight! 😊