What are the reasons to think we are living in a simulation?

Every time I need to cross a seemingly empty street, suddenly cars appear. I can't help but imagine it's a render distance issue.

Try to cross the street without turning your head. When you turn your head, they render the cars in the opposite directions.
/jk always look both ways before crossing the street.
- I've got a spinbot for crossing the street to exploit the universe's shoddy hitboxes

The render distance (observable universe)
The pixel size (Planck units)
And the update rate ('speed of light' = speed of information being updated)

Calling Planck units "pixels" is extremely reductive. This is just naively applying video game concepts to physics with a poor understanding of both.
- I took an entire graduate course in QM and a quantized Universe does, in fact, seem pixelated. That's exactly how I explain it to people. There's simply a finite level to how closely you can zoom in. Space, time, and energy are all quantized, and maybe even gravity though we haven't figured that one out yet.
- I took an entire graduate course in QM and a quantized Universe does, in fact, seem pixelated. That's exactly how I explain it to people. There's simply a finite level to how closely you can zoom in.
Status not being updated if no one is looking at it (Schrödinger's cat, quantum entanglement)

Simulation theory is more or less a kind of modern creation myth, and creation myths are based around its societies current level of understanding of the world. In ancient times people explained the worlds actions and existence through gods and imaginative myths. When the scientific revolution happened people explained the universe in terms of immutable laws and cosmic logic. Now we are in the computational revolution, thus some people explain the worlds existence through computers. All untestable and unfalsifiable explanations for the nature of reality are as good as any other, so pick your poison and enjoy!

Simulation theory comes from solipsism, and it's not that modern. According to Wikipedia it originated in Greece in 483–375 BC.
Every human is solipsist until about 2 years old, when they start to realize that the world is not revolving around them. It is called "crisis of 2 year old", or "terrible twos". Some people don't get to go through this at 2, especially the children of billionaires, who have no reasons to think that they are not the center of the universe.
- The danger of this approach is that you start treating other people as NPCs, dehumanizing them. When others are not real people, you don't have any problem with robbing, raping or murdering them. See the "Westworld" series for more deep analysis.

According to some, assuming it's even possible to fully simulate a universe to the degree that life in it can't tell, then there should be multiple simulations running, so there would be more sim-universes than real ones, and odds would be high that any given universe you find yourself in would be a sim.

Personally I don't buy it, I think if we were in a sim the laws of physics would have to be easily computable (they aren't, see gluons) and I think it would take the computing power of an entire universe to simulate one of similar complexity at anywhere close to reasonable speed. (Note how emulators and virtual machines can only emulate a weaker system then the host system, at least at speeds comparable to native hardware)

- Exactly. Liu Cixin's trilogy Remembrance of Earth's Past has some great writing on different technological levels between alien species and how one could influence a lower tiered civilization by using physics.
Thanks for typing out what i was gonna say.
I am agnostic about simulation theory. If an advanced enough “something” can create a simulation undistinguishable from the lives we experience now then i would bet that we do live in one. But thats a big if and goes a bit further than one where life cant tell. (A simulated single cell organism is miles of from simulated mammals and society)
there would be more sim-universes than real ones
This ties back to the mediocrity principle. If there are 10 billion people living on Earth, but 10 quadrillion living in simulations, the chances for you to live in the latter is much higher.
Along goes the simulation argument by Nick Bostrom. If simulation is possible, and practiced, we likely are simulated ourselves.
Isaac Arthur) noted that housing a population in a simulation is much more efficient than doing so physically. It seems like a convergent choice for powerful civilizations which want to maximize the life supported by fading stars (or energy potentials in general).
I think it would take the computing power of an entire universe to simulate one of similar complexity
Two objections:
It might be sufficient to simulate the experience, without fully simulating the underlying physics. That's how we do 3D games anyways. No one cares if we actually simulate individual air molecules. If the cloth moves indistinguishable as if, that's as good as the original, for a much lower cost. You can also cull unobserved parts of the universe.
Host and simulation can have completely unrelated laws of nature. Specifically, inhabitants of the simulation cannot study their host environment. As such, I think making assumptions about the host makes no sense.
- Those are some really interesting points, thanks for your input.
How much would speed matter to a simulated lifeform. Ive often wondered if time would suddenly stop and then continue we would probably just experience it like it didn’t stop.
but time is relative. we might very well live in a simulation that takes a minute of “external time” to compute a single tick of our time. we just can’t experience it.
I'm not really a believer of the whole simulated universe theory, but I find your arguments against it weak.
You're basing what is and isn't easily calculatable off of our experiences. Same with "complexities of the universes". However, if our world is indeed simulated, there's no telling what the host universe is like. It might have crazy different math and be far far more complex than ours. Us trying to understand it would essentially be an excercise in futility.

You cannot disprove this hypothesis and it's cool. Quite literally nothing can support it - if we live in a simulation, every part of the universe makes sense for us because we have no reference frame for "real" physics.

It's just something fun to think about but ultimately it doesn't matter, you have no way to find out.

It gives comfort for people who don't adhere to any of the major religions but still need to feel like there is a hidden meaning to existence and something bigger than the universe.

At this point does it matter? If it turns out tomorrow we have proof we live in a simulation, it doesn’t make my life any less real. I still gotta go to working tomorrow lol.

Yea it really wouldn’t matter other than having religious dogma change or about what happens after death.
It’s more of an interesting thought experiment about the seemingly minuscule chances of life forming and us being/experiencing life.

The idea that it's theoretically possible that we would be able to simulate a universe of our own leads to the hypothesis that we could be living in a simulation ourselves.

That very much reminds me about the reasoning of Descartes why a god must exist: basically because he can think about it.
But really, just because you can think of it doesn’t make anything theoretically possible. For the simulation of a universe we have no idea how to do it.
- I think that's a poor analogy.
  It's true that we're not capable of stimulating a universe in appropriate detail presently, but it's inevitable that at some time we will have that capacity.
  Looking at progress in the last 20 years, and extrapolate another thousand years, it's entirely plausible that one could spin up a "universe" on a personal device to play with.
- We could already theoretically simulate a universe; our only limiting factor is the amount of power we have available to us.
  It might not be identical to our own universe as we are still missing the necessary knowledge to do that, though who's to say our host universe has the same laws of physics etc. as ours? It's not necessary to simulate our host universe, though rather a universe with a specific set of parameters that we decide on.
  That specific set of parameters were likely chosen for our own universe.
If you believe it’s possible we could create that simulation (and why would we only do it once), then it follows it would possible for that simulation to create it’s own simulations. And so on and so on.
So if it’s possible, then it’s all but impossible that any of this is real.
- The first ~~mover~~ stimulator theory - we are God.

What does it mean to "live in a simulation"? If I created a sentient computer program that has no contact with the outside world then you would say it's living in a simulation, but if you took that same exact program and connected it to a robot you'd say it's living in reality. But what's the line? If you add a tiny glimpse of reality but 99.9% of its experiences are stimulated is it living in a simulation or reality? It's not necessarily a black or white thing but more like a spectrum. In that sense you could say that our brains are creating a simulation of the outside world based on real inputs, but our perception of reality is not necessarily accurate. I would say our brains are on the spectrum of being a simulation of reality because not everything we experience is necessarily real.

Aliens could land on my lawn and take a 10hour long shit and I'd still have to go to work the next day.

For a slightly different take, a simulation and reality are not that fundamentally different given how both are perceived by senses in a similar way. Like how a VR headset uses the same sense that you use to see real objects.

They start to diverge in a way when you start encountering edge phenomenon that are beyond the scope of the simulation, like how a game would glitch. So far, however much we zoom in or zoom out, reality works consistently. So it is less likely that we're in a simulation.

It depends how you define reality working consistently. Dark matter was first theorized by observing how galaxies and star clusters etc don't seem to have enough mass to produce the gravitational footprint that holds them together. So dark matter was theorized to account for it. Invisible, intangible matter that only interacts with "normal" matter through gravity. Kinda strange 🤔
- I mean we knew that gravity as we understood in terms of GR is not a full picture. As people figured out that the expansion of the universe was accelerating, which would be impossible if gravity was simply attractive. So I don't think of dark matter as a glitch. It's more like a placeholder we don't understand yet.
  Something that seems like a glitch to me is speed of light being a hard limit, but when you really dig into it you realize that certain limits determine the nature of the reality and they need to have some fixed value like the speed of light went Planck's constant.

I think it's a contemporary way of viewing the creation problem that religion has also been trying to address. Who created the universe, and who created the one who created the universe. What caused the Big bang. Etc.

The whole thing is irrelevant in my opinion. It doesn't matter, because whatever initialised existence is outside of our existence. That would be separated in dimensions, or even if we could interact with it, it would at least be in a completely different frame of time. The entire existence of our universe could be a blink of an eye in whatever is outside of it.

It seems like megalomania to me for humans to believe that they can ever figure this one out. Just like the microbes in our bodies can't interact with us, I don't have any hope for humans to ever understand how the entire universe interacts with it's creator, whether it's a simulation, a devine creation or the result of physics.

If it's a simulation and we are just variables in a sub-routine, then its futile to claim that we can ever figure out what is outside our loop. We can catch global variables from the main loop, like natural constants, but we'll never see the code that calls our sub.

The only reason to believe it is that we can also not prove that it isn't so. Someone claims that it's statistically unlikely that it's not a simulation but I'm not so sure about that argument. It's based on an extremely deterministic view, that everything can be simulated with enough computer power, which itself is a questionable view.

I'm a weak solipsist - I firmly believe that "I think therefore I am" is the only truth we can know. Everything else, we take on faith.

That said, it doesn't really matter. We live in the reality we perceive. There's no practical difference between living in reality and living in a simulation.

Because Elon Musk believes in it, I know it’s probably wrong.

Simulation theory is more or less a kind of modern creation myth, and creation myths are based around its societies current level of understanding of the world. In ancient times people explained the worlds actions and existence through gods and imaginative myths. When the scientific revolution happened people explained the universe in terms of immutable laws and cosmic logic. Now we are in the computational revolution, thus some people explain the worlds existence through computers. All untestable and unfalsifiable explanations for the nature of reality are as good as any other, so pick your poison and enjoy!

The limits of physics could be a rendering limit on the simulation hardware.

Because thinking that we are here for no specific reason is scary

It's not an "either/or" situation. I don't think we're in a simulation, but that doesn't mean we're here for hi specific reason. We're obviously here to live, and to help each other out of the darkness of ignorance and into the light of understanding while they live. That's literally our purpose, and so much of what we do is geared toward that. I guess people are looking for something deeper, but that seems plenty deep to me! If you're not actively trying to help the people around you, you're going to feel empty, like your life has no meaning. Unless you're a sociopath, which is definitely a thing. But most of us are not. Most of us just want to feel like we're doing our part, so we should keep that in mind.

Musk's leadership of Twitter. if we're in a simulation it makes perfect sense - some admin forgot to flip a switch somewhere and shit has gone a bit off the rails

I don’t see any reason to think I’m not in a simulation, except that it’s just a silly ancient fable, created by the simulation. but none of that affects the “realities” of life and love all the rest of it.

Once I learned about quantum field theory, the distinction between reality and simulation kind of went away for me. It says that all of reality is essentially number values for different fundamental fields. A particle exists when the value for this field is d and the value for that field is y. But the only fundamentally real things are the fields. Everything else are just a configuration of number values within them that together conform to mathematical logic.

This sounds a lot like software to me. Whether it’s running on quantum fields or a fucking Pentium 3 doesn’t seem super important.

So sweeping aside the technology as irrelevant, we have turn to the issue of whether the universe is contrived by programmers. The question becomes: did people create the universe? And my opinion of us just isn’t that high.

I read a series, can't recall the name anymore, but computer simulations were so powerful that the entities within the simulations would think they are alive. In the novel this was done to try and simulated conditions to predict real life outcomes. It was also considered particularly vile and cruel to do this and illegal in some cases. Particularly if the simulated entities realized their situation and knew they would be turned off or understand their past was all made up.
It definately makes you wonder.
- Just like we think we actually have free will, and are pretty upset to find we don’t, and are going to die.

If you have the fundamental belief that if we know every single possible detail down to the atom, that we can predict what will happen every time, then you believe that free will does not exist. If you think of it that way, and think everything is calculated, then it could be theoretically be possible for some kind of super computer to generate everything since it knows all the information and can calculate what will happen next.

I also think that free will may not exist, but I'm not sure why. Either everything can be calculated in advance as you say, or everything is fundamentally random because quantum mechanics. But maybe there's something at the edge where neither of these explanations are correct? What happens there?

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Damn I spent my last kvazon at the pizzeria do yall take credit?
- Yes, but you'll regret it later, in about 20 years.

Here’s Elon Musk’s argument (not saying I agree with it but here’s what he said about it):

Eventually we will be able to create entirely convincing simulations. Just look at video games. The graphics are getting pretty good.

So given that we will inevitably create such simulations, we have to ask whether it has perhaps already happened and this is one of them.

And since we will no doubt create many different simulations, millions of them, the odds are against this one being the prime reality. It’s just millions-to-one odds by the numbers.

Therefore this is almost certainly a simulation.

(Personally I think there are factual and logical problems at many steps in this)

I just want to point out that while Musk likes to parrot this rhetoric, it is Nick Bostrom who should be credited with the hypothesis in its current, modern incarnation. That's not to say it is entirely his idea either, as similar hypotheses have been pontificated over for centuries , notably by René Descartes.
- Mm thanks. Worthy footnote.
seems consistent..

What's the difference?

I wrote a much longer comment that was lost (still missing client features from Reddit clients like draft saving).

The TLDR is a lot of the physics behaviors we have in our world relating to quanta (as many others have mentioned), but especially in combination with a ~2,000 year old text and tradition which claimed the most (in)famous person in history was saying we are in a non-physical copy of a dead original world made by a light-based intelligence brought forth by the original humanity, and that the proof for this was in motion and rest - particularly that the ability to find an indivisible point within things would only be possible in the non-physical physical.

So in an age where humanity is on the cusp of bringing forth new intelligence, ever more looking like that will occur in light (optoelectronics), where we are creating digital twins of ourselves and the world around us, where a trillion dollar corporation has already been granted a patent on digital resurrection of the dead, and where the virtual worlds we build often use rendering tricks similar to the behavior of our own world at low fidelities -- that's pretty weird to have existed so far back in antiquity.

Almost like it would be more likely to exist in a simulated world, much like how many of our own virtual world have 4th wall breaking acknowledgement of being virtual buried as an Easter egg in their lore...

What 2000 year old thing are you talking about?

It's based on the idea that if we were, we wouldn't be able to tell the difference.

My life is “Murphy’s Law: the Movie”. Every time I try to reassure myself by saying “well, at least it can’t possibly get any worse than this”, it gets worse. There’s no way that there isn’t some asshole running a simulation where they just fuck with me.

Ever wonder about reasons to think we are not living in a simulation?

Because everything can be expressed mathematically.

Math and physics. (Almost) everything can be calculated, and the stuff we can't calculate is probably because we haven't discovered the constant/formula yet.

Doesn’t sound any more ridiculous than any of the other ideas.

I'm still waiting for Pi to start repeating so that we have proof.

The Library of Babel isn't pre-written or cached. It's an algorithm to generate text. Huge difference.

All text has already been written. Everything you ever read was already cached for easy access, even this comment.

I never see my neighbors bringing groceries into their house.

All text has already been written. Everything you ever read was already cached for easy access, even this comment.

Everything there is is made out of atoms, Just seems to easy to me, like 0s and 1s in Matrix

but atoms are made by particles, and particles are made by gluons, which are made of… strings? quantum foam? we haven’t hit rock bottom yet.

The fact that this question gets reasked every five seconds.

All text has already been written. Everything you ever read was already cached for easy access, even this comment.

Herd mentality is very weird. People who would never, on their own, commit crimes/violence just kind of start doing it. Almost feels like that “god hand” player controlling the RTS ordered a group of people to do their bidding.