
Is reality a computer simulation? Does it matter? - RV86
http://aeon.co/magazine/science/can-we-tell-if-reality-is-a-computer-simulation/
======
skywhopper
These ideas may be fun to think about, but ultimately they're meaningless.
It's certainly not a new idea that some being on another plane of existence
brought our universe into being on a whim, and can modify the parameters of
its existence at will.

If that's so, it's highly unlikely we'll be able to poke any holes in it. Nor
is there any reason to believe our memories or any of history is real. Maybe
scientists have poked holes in the simulation a million times, and each time,
the supreme Code Monkey suspends the simulation, fixes the bug, and rolls back
the state to before the hole was poked.

For that matter, it's silly to believe that our puny existence has even been
noticed by whoever spun up the entire Universe.

Most of the questions that this premise supposedly solves are mostly based on
fallacious reasoning. Why is the universe fine-tuned for us? What are the
chances of this specific universe? How likely is it that intelligent life
exists on our planet? You may as well ask what are the chances of your
particular DNA sequence. Just because your specific genetic code is extremely
unlikely doesn't mean it's impossible that you exist.

Ultimately, such an idea only raises more questions. So, say we are in a
simulation. Now, how does the "real" world work? Where did it come from? How
do we know _it_ isn't a simulation?

If these are the answers that make the most sense to you, you've stumbled down
the wrong path, and it's time to take a fresh look at the world.

~~~
tzs
> If that's so, it's highly unlikely we'll be able to poke any holes in it.
> Nor is there any reason to believe our memories or any of history is real.
> Maybe scientists have poked holes in the simulation a million times, and
> each time, the supreme Code Monkey suspends the simulation, fixes the bug,
> and rolls back the state to before the hole was poked

I suggest you track down and read the Asimov short story "The Last Answer". I
think you will enjoy it. It deals with a similar situation to what you
describe, although not quite in the context of a universe simulation.

------
dwild
This idea of a computer simulation is what made me become agnostic. At first I
was an atheist, I wasn't believing that any powerful entity would create us
like this, a world so complex and coherent, just to test our belief.

If I had the capacity to build this kind of computer simulation, I would
personally do it in an heartbeat. In fact I'm feel like I'm doing this on some
games. I would also consider myself to be the god of that simulation, I'm
omniscient, omnipotent, omnipresent, etc...

That's why I believe there could be a god, it's possible that he isn't even
aware of our existence and he is just currently playing a big game of Universe
Sandbox. However I also came to the same conclusion of that article (at least,
based on the title, I still haven't read it, it's on my to read list), does it
really matter?

~~~
duaneb
In my mind, I dislike the 'computer simulation' because it implies an entity
that computes, which doesn't really make sense without an uber-reality. Such
teleological thinking doesn't belong in scientific reasoning (or even,
frankly, philosophy).

~~~
dwild
Could you define "uber-reality" and explain how it doesn't really make sense?

~~~
saraid216
The issue he's talking about can be pretty easily illustrated with "turtles
all the way down". A simulation must be, by definition, simulated _by_
something that is external to the simulation itself.

If this isn't infinitely recursive somehow, then there must be an instance
that is _not_ a simulation. This is the uber-reality he speaks of.

~~~
dwild
Ok yes I understands. Thank you.

It all depends of the definition of gods, like I said, if it's omnipotent,
omniscient, omnipresent, etc.. then I feel like we can consider it our god
which would include the one that made our simulation. That would means that
they would respect that definition of gods towards us. In the same way,
nothing stop gods from having gods themselves. I don't know too much about
gods but don't some Greeks gods had some sort of power over each other? It's
all relative in a way.

I'm also not actually believing it's the truth too, I'm just acknowledging the
possibilities. I don't believe usual religions because I find it hard to
believe their "why". The computer simulation does have a why that I believe
could be a possibility.

------
benekastah
> Should any error [in the program] occur, the director could easily edit the
> states of any brains that have become aware of an anomaly before it spoils
> the simulation.

This seems really problematic to me. Why would you assume that a full-on
universe simulator has a concept of a brain? If you're in the business of
simulating the interactions of nanoparticles, having a "brain" object doesn't
seem to make much sense. I suppose that you could implement some heuristic to
identify minds with some degree of accuracy, but then you're getting into some
weird territory. Someone wants to model the _entire universe_ just to observe
life here on earth? Why assume the author of this system is even aware of us
at all?

> It could be the case that one planetary civilisation is all that can be
> simulated, without running into computational capacity issues.

Again, why would a system like this be optimized toward the civilisation
level?

The idea is cool, maybe probable, but this write up seems pretty fanciful.

~~~
duaneb
It seems to be a thought experiment in torturing the inhabitants of a computer
simulation. How else would you pose the question "Is this a reality that may
be modeled, or a simulation of a model?" If it's a perfect simulation, there
is literally no difference to the inhabitants. If it's not a perfect
simulation, then the experiment being run is what differentiates this model?
The answer is clearly those conscious of the problems with the model and how
they react. And if a physicist ever seriously posits we're in a simulation,
they had better have better evidence than "because humans are interesting".

Anyway, until we fuzz physics enough to detect inconsistencies in (e.g.)
conservation of energy, this is an entirely fanciful and useless topic. If I
may bring in Plato's allegory of the cave, it's fairly clear this line of
thought is only useful if we can detect and/or manipulate it. Until then, it's
fairly absurd to think what we may be "turning our back to" in the cave when
we are unable to even figure out if we have a back.

~~~
sosuke
Perhaps we are the control, and other simulations have the variables.

------
blacksmith_tb
Obviously this is a theme that has been explored in SF a fair amount (recent
examples include Ken Macleod's The Restoration Game and Iain Banks' Surface
Detail). One obvious problem is that it appears to be highly immoral to
generate a simulation in which millions or billions of sentient beings suffer,
which presumably would weigh heavier on a more advanced species (human or
otherwise).

~~~
georgemcbay
It is pretty easy to ignore the suffering of others if you can convince
yourself that it is a different and simpler form of suffering than you feel --
just look at how a lot of humans (and I'm talking about ones that are accepted
by society, not crazy psychopaths) treat animals (eg. circus elephants).

~~~
infogulch
Exactly. For a being that is capable of simulating the entire universe at the
quantum level we may be no more "sentient" in their minds than ants are in our
minds.

------
tjradcliffe
There is a very general argument that we can't simulate anything remotely
resembling our universe inside our universe:
[http://www.tjradcliffe.com/?p=1220](http://www.tjradcliffe.com/?p=1220) Short
version: at the precision required for the degree of agreement we see between
theory and experiment, we could simulate at most 0.5% of our universe, which
simulation would not be capable of star formation because there wouldn't be
enough matter in it, and a universe "above" ours that was simulating us would
collapse immediately after the Big Bang because it would contain at least 200
times as much matter as ours.

The responses to that argument are two-fold:

1) start madly making up increasingly implausible auxiliary assumptions to
save the claim that we might be living in a simulation

2) admit that the odds we are living in simulation are rather low, and in
particular the argument that we almost certainly are thanks to recursion is
extremely poor.

I favour the latter response, as the former seems to involve either claiming
that the universe that is simulating us has fundamentally different physics,
or that the simulation isn't actually a simulation but rather a game-like
approximation that somehow gets updated with sufficient local detail that no
matter what kind of experiments we do or observations we happen to make, there
is special-case code for ensuring the results look like a consistent
underlying physics.

Claiming the universe simulating us has fundamentally different physics
requires that we drop any claims about it based on the physics of our
universe, in which case it becomes untestable because anything we see may or
may not be due to a simulation being run in a universe whose laws are not like
our own.

Claiming the approximation is fixed up by special-case code whenever anyone
thinks of doing an experiment or making an observation that might reveal the
lack of a full physics engine is likewise putting the hypothesis beyond
testability.

So either the simulation hypothesis is wrong, or untestable. Neither of these
is very interesting.

~~~
joaorj
What would you say when, in a few years (or few thousand), we develop a rather
crude simulation (compared to our universe) where sentient life forms emerge?
And what would you say when they point out the exact same argument you did for
them not being in a simulation?

The only valid answer, I think, is that nor we, nor any other lifeform, will
never be able to do so. And it's impossible to predict whether we will be able
to do that or not, but everything points out to the answer being yes!

But please, give me an answer I didn't think of.

PS: I completely hate the simulation argument, as it stands, as you can see in
my answer to the top post.

------
sosuke
The speed of light is just a clever hack for rendering performance much like
binary space partitioning made the rendering of our own early 3D worlds
performance good enough to enjoy.

------
steven777400
I think there could be some interesting conclusions or capabilities from being
in a simulation.

First, we would expect that the simulation may use heuristics; that some
things not "observed" may be simulated in a quicker or more crude way.

Second, there may be a way to access the computational substrate. If the
universe exists within a simulation, is there a way to run software directly
against the universe "computer"? Are there security vulnerabilities in the
simulation that could allow access to the higher level substrate, either to
discover more about it or enact otherwise impossible changes in our universe?

Finally, there is the potential for external threat. In a simulation, one time
step may take a variable amount of "real" time to complete. If we do find a
way to tap into the computational substrate, or otherwise find some actions
that burden the simulation excessively, the amount of time each of our
universe's timesteps takes to complete in the external host "universe" will
increase, possibly to the point where the author of the simulation
interventions to correct the problem.

~~~
Freestyler_3
In a simulation where there are things such as awareness, there must be some
sort of firewall protecting the computer from attempts to try and run our own
software. First you would have to find out how this computer works, because it
is nothing like ours.

I mean our simulations are just code running calculations, we don't have code
that gives our programs a self awareness. I would say this would be many
simulations, unless they are only running my point of view and you are all
just simple code. You see we are all giving output then we are all small
simulations together If it is just me then they are just looking at my output
and you are just something I interact with, I cant tell if you can see, feel
or make your own choices.

Anywho, whatever we are, we are.

And its not unrealistic for scientists to try and simulate something with as
much detail as possible. If we simulate 3 planets, we give them a (to us)
realistic colour representation. If you are simulating a world with beings
that experience the simulations as if it was real life, you could easily make
them all the same but not make them realise. But why wouldn't you make a real
representation.

------
madaxe_again
1) Probably.

2) No.

Hell, even if it isn't, is time real? Is anything? Or do we create the reality
we perceive through our perception of it?

Mused the other day on Descartes, and "je pense, donc je suis" is
tautological. Everything is, as any definition of anything by us is inevitably
from our reference frame, and is based on precepts we aren't even aware of.

~~~
duaneb
Existence itself is a tautological attempt to bind language to reality. I urge
you instead to view Descartes as a framework for building on perception
(thoughts) and reality/existence (that which emerges from perception).

------
nemo44x
If it's the case that we are currently a part of a simulation then we can
assume those above use are part of a simulation too and eventually we will
create a simulation below us and it's turtles all the way down....and up.

~~~
vbezhenar
That's why the simulation hypothesis is quite likely. We can simulate very
simple universes. We will simulate more complex universes as time goes on. And
there's nothing to prevent that universes to become really complex, so complex
that beings there will become conscious. And it's only matter of time when
those beings will simulate another universe.

And, considering that every civilization simulates many universes, there's an
exponential growth of universes beginning from the "root" civilization. So
there are (or there will be) billions of billions of universes, one inside
other, like russian dolls. And possibility of us living in the "root" universe
is quite low.

Either that or there's some fundamental nature law preventing us from creating
a simulation of conscious intelligent mind. And even if we didn't create that
simulation yet, I don't believe that those laws exist. We have billions stars
to consume for energy and matter and billions of years to improve our
technology. Why don't we create megacomputers with that power potentially at
our hands?

------
alphaBetaGamma
It seems to me that a consequence of the second principle of thermodynamics is
that your simulations are always going to be (much) smaller than your
resources (I'm using the word loosely).

So you can't go very far down the road of simulations in simulations in
simulations before the "deepest" simulation is to small to have conscientious
beings. So the argument that we are in all probability in a simulation seems
to break down.

------
givan
People always saw the universe based on their current knowledge, in the
digital era we believe it's a computer simulation some time ago we thought
there were turtles all the way down.

We are still at the philosophical stage, science is too young for these kind
of answers so the question is when we will reach the necessary knowledge level
to comprehend it and if this is possible because we are also part of it.

------
squozzer
The notion of simplification, which I hadn't considered, might explain - if
testable - certain things such as Heisenberg's Uncertainty Principle, i.e.
limiting the precision with which one can measure a particle's position or
momentum would make it more difficult to discover the underlying true reality.

I'm tempted to use Occam's Razor but probably can't because the simulation
hypothesis assumes an intelligence created it. And intelligent beings have
demonstrated more than once the capability for subterfuge.

I think to test the simulation hypothesis one might have to assume a couple of
things - 1) the sim has resource constraints, otherwise the creator might as
well build a real universe (thanks to Pete Bonani of Falcon 4.0 for sharing a
similar insight); 2) every object in the sim has a state and a function which
acts upon that state.

I'm not sure how someone inside a sim might test these assumptions though I
suppose we could try making babies and hopes that overloads the sim before we
run out of food.

~~~
AnimalMuppet
Occam's Razor doesn't _disprove_ the idea. It merely suggests that it is a
less likely explanation.

------
srean
An aspect that the blog post did not get into as much is what does it mean for
something to be a computation or a simulation. Formalization of computation is
well trodden ground.

Lets take the state transition view of it. Our PCs, phones or any other
physical thing that we agree is a system 'that computes' is just following the
laws of physics, or state evolution. We engineer the initial condition so that
it converges to something that is of interest to us. So does it mean it is
necessary for the existence of a conscious observer / intervener / interpreter
of state for something to be deemed a 'computation' ?

Even if no one is there to observe a particular state or have interest in it,
if the system happens to be initialized at some state it would 'compute' the
result (end state) no matter what. So what would be that fundamental
difference between a simulation and a universe following physical laws ? I
think the issue is not whether this is a simulation but whether someone is
consciously simulating it. The thing is that it need not be an external
entity, embedded entities themselves may reside (perhaps voluntarily) in a
simulated experience (hallucinogenic drugs), insanity (socially imposed
conformance / compliance), schizophrenia.

The notion of reality is messy business that ties one up in knots. What I find
interesting is how two ancient cultures : (i) native American and (ii) Indian
thought about it, how they answered when I am dreaming is that real or is that
fake. It is really hard to argue that what we call real is a more privileged
position than the dream world or a hallucination when we are in it. Some
native American philosophies decided that both are equally real. If some one
flies in a hallucinogenic trip the person is really flying in that world.
There are ways to get in and out of those worlds. The ancient Indians or the
vedic philosophers took another route, they chose that both these worlds are
just equally unreal.

The question of whether this real or not is pretty much as old as thought.

------
AnimalMuppet
There seems to be this background idea here that "If you can't disprove it,
that means it's plausible," which is totally mistaken. Not every idea that we
can't disprove is worth seriously considering.

Let me put it this way. If a fundamentalist Christian made the same kind of
arguments, and said "therefore God probably exists", would you believe that it
really was probable? Most likely you'd say "I'm pretty sure that God doesn't
exist, even if I can't prove it, and I'm not going to change my view of the
probability just because this person says something that sounds good." But if
you think that's a reasonable response, why is not the same approach
reasonable in response to this "the universe is probably a simulation" stuff?

------
adamio
You could say our consciousness (and imagination) is a simulation running on
our brain

------
danbruc
Maybe I am ignorant but trying to distinguish between simulation and reality
seems to me a lost case right from the beginning. You have to look for a
difference but we know neither the rules of the simulation nor of reality. If
we look at the universe and find a difference between what general relativity
predicts and what the universe does, maybe it even looks exactly like floating
point rounding errors - this tells us nothing. It might be an imprecise
simulation but it may as well be that general relativity is just an
approximation and the real behavior of the universe is floating point general
relativity.

------
tehwalrus
Energy, though.

I mean, the host universe may have completely different laws of nature, but
assuming that the 2nd law exists in it...

Organising information (storing it in RAM, carving it on a rock...) decreases
entropy and thus takes work (entropy overall increases, because you had to get
the energy to do your work by increasing entropy somewhere else by more.)

The cost of accurately simulating an entire universe, down to atoms, would be
_extreme_ , like you'd need galaxys worth of stars' to even begin.

At which point, the question becomes, why not just observe the real universe?

~~~
delinka
You assume that our [observable, hypothesized] universe isn't a pittance of
matter and energy in a larger universe. Suppose your Conway's Game of Life
simulation gained what it considered sentience, and with this sentience
contemplated whether this world it inhabits was the universe or a simulation.
Now suppose that it deduced that it would take _universes_ of energy to
simulate its own universe. Well, it'd be right.

That doesn't mean it's not.

~~~
tehwalrus
Indeed, if the D&D universe is the real one, we may all be in some elven
wizard's toy universe, with "simple" rules and no magic, where she goes to
meditate... I did try to caveat in my original answer.

------
ChrisGranger
"However, Bostrom recognises that a complete emulation of reality on every
level is likely to be impractical, even for powerful computing systems."

Doesn't this assume that the simulation is running in a universe where our
laws of physics apply? Couldn't what we think of as our laws of physics be a
programmed part of the simulation, running on computers in a completely
different universe where it's impossible for us to do more than speculate on
matters of practicality?

------
sukruh
> Simulating an entire Universe with sufficient detail to include conscious
> minds will be complex, even if the fundamental rules underlying the program
> are simple. It seems needlessly baroque to programme something as
> complicated as that, when you can learn just as much from something simpler.

Scientists and engineers use many-body simulations to investigate emergent
properties of systems all the time. Not all understanding comes from first
principles only.

------
imranq
I really like this short story that illustrates the concept:

[http://qntm.org/responsibility](http://qntm.org/responsibility)

------
logicallee
Are you kidding! Of course it matters!! If it's a VM, we can start hacking it,
until we find the universal equivalent of a buffer overflow or some kind of
edge case branch mispredictoin, and can start injecting our own payload. After
a little bootstrapping, and experimentation that hopefully doesn't crash the
VM, we are now running whatever physical laws we want. Matrix time!

~~~
vbezhenar
Or some watchdog system will detect an abnormal behaiour, stop the simulation
and report the bug to the developers. They'll fix bugs and run the simulation
from the last non-corrupted backup. And we'll never know that someone did
that.

------
vonklaus
I have been giving this a lot of thought lately, especially after reading
Superintelligience. I actually think that it is somewhat likely, or even
highly probable given how we would model out our own behaviour and hardware.
Further, to use a video game analogy, we may actually be non-primary
characters, that are being modeled by a different, more sophisticated, group
of actors.

~~~
ThomPete
Which still doesn't solve the whole first cause question (and doesn't have to
of course)

------
bjackman
If you're interested in this idea, here's a fun short story:
[http://qntm.org/responsibility](http://qntm.org/responsibility)

Also, Permutation City by Greg Egan is a good read.

------
viggity
Thinking about this is a fun little exercise, but I hope nobody becomes a
nihilist over it. Because fuck nihilism.

~~~
xj9
Whats wrong with nihilism?

------
islon
If our reality is a big simulated game I only wanted to have access to the
developer console...

