July 03, 2011
If We Are In A Computer Simulation

Is the universe just a big computer simulation running in another universe? Suppose it is. Then I've got some questions:

  • Are intelligent entities modeled as objects? In other words, are they instantiated and managed as distinct tracked pieces in the simulation? Or is the universe just modeled as huge numbers of subatomic particles and energy?
  • If intelligences aren't modeled as objects are they at least tracked or studied by whoever is running the sim? Or is the evolution of intelligence in the sim just seen as an uninteresting side effect and irrelevant to the sim's purposes?
  • Is The Big Bang the moment the sim started running? Or did it start long before that point? Or has it been started at a much later point with data loading in to make it look like it started earlier?
  • Do the creators of the sim intervene as it runs? Do they patch it?
  • What is the purpose of the sim? Entertainment? Political decision-making? Scientific research?
  • Were the physical laws of the universe designed to reduce the computational cost of the sim? If so, what aspects of the physical laws were designed to make computation cheaper?

Imagine the purpose of the sim is entertainment or decision-making. Either way, it could be that out-of-universe sentient beings actually enter this universe and interact with some of its intelligent entities. Interact with simulated people for fun. Or interact in order to try out different experiments of political development. In the latter case I would expect more rerunning of the same sim backed up to restart at the same point but with some alteration of what some people say or do.

So what's your (simulated) gut feeling? Are you in a sim? If so, what's it for?

Update: Some commenters wonder why simulate a whole universe unless you want to simulate intelligence? Maybe the outer universe is many orders of magnitude larger in numbers of stars and planets and they want to see what a less crowded universe would be like.

Here's an even better idea: Suppose the real outer universe has massive planets all in close proximity. Suppose they have quintillions of people who are all very similar in this highly interconnected universe. So there's no diversity of intelligent life forms. So they decided to create a universe sim where the stars are so far apart that each intelligent life form evolves separately and is different in many ways. This provides the homogeneous simulator people experience of greater differences than they can see in their own universe.

Update II: Maybe we all suffer from the Dunning-Kruger Effect and can't grasp the extent of our mental deficiencies that render us unable to grasp the motives of the sim writers. There could be motives beyond our ability to suspect or conceive.

Share |      Randall Parker, 2011 July 03 09:36 PM  AI Simulations

MC said at July 4, 2011 12:25 AM:

It's "just" a "big" sim? A mere bagatelle?
Seems a lot of computational power (and energy) would be required. The universe makes 'big' seem small.

jens said at July 4, 2011 12:49 AM:

My gut feedling is, that it's not really simulated in the sense that it's running on a giant computer operated by some extrauniversal entity, but rather that the rules of the universe at the most basic level are discreet and computable, so that the universe and a simulation thereof would be indistinguishable.

PacRim Jim said at July 4, 2011 1:44 AM:

If it's a simulation, perhaps there is no arrow of time in their universe, so the simulation is running backward, with reversed causality.
Perhaps the simulation is running on networked Sinclair and Coleco computers. That would explain much.

PacRim Jim said at July 4, 2011 1:55 AM:

Also see Laplace's demon in Wikipedia.

Brett Bellmore said at July 4, 2011 4:19 AM:

My own position is that I can't see anybody lacking in better uses for computational power, so you'd REALLY be hard put to convince me it's all a simulation.

bbartlog said at July 4, 2011 6:07 AM:

@Brett: OK, so now explain World of Wacraft :-)
I've become better as I've gotten older at not worrying about stuff that I can't possibly answer. You know, religious questions and also stuff like this. You just don't have enough information about possible metaverses to have any notion as to why, how or whether a simulation would be run. Now of course if the simulation were flawed ('glitch in the Matrix') then some information could be gleaned, but that sounds like an optimistic assumption.

Brett Bellmore said at July 4, 2011 6:40 AM:

That's a game, not s simulation. Life isn't exciting enough to plausibly be a game. Unless, of course, we're only NPCs, with our sociopathic heads of states the actual players... I found this novel on the subject quite entertaining.

With the thoughts you’d be thinkin said at July 4, 2011 7:27 AM:

The only game I can think of that is comparable to such a hypothesies is Dwarf Fortress.

xxd said at July 4, 2011 7:59 AM:

IF it's a sim then I know I'm not one of the alien players because I want to win the lottery and I haven't, so I'm just a simulated cog with no free will.

JS Allen said at July 4, 2011 9:16 AM:

We are definitely in a sim. It was created by aliens in another dimension who want to map out the physical laws of the 4 dimensions that this sim inhabits. They are harvesting our scientific knowledge, and will shut off the sim as soon as we have the answers they need.

As such, I recommend surreptitiously poisoning our scientific literature and stalling progress indefinitely.

Also, One 96
hour rotating Cube within a
single rotation of Earth - is a
SuperNatural Transcendence.
Bible and Science falsify 1
corner day for the Cubic 4
corner Days rotating daily.

jamie b. said at July 4, 2011 1:01 PM:

"Or has (the simulation) been started at a much later point with data loading in to make it look like it started earlier?"

Another possibility is that the simulation hasn't even started yet, and we only exist as the "data loaded in to make it look like it started earlier." But I suppose that this only points out why a hard-core Platonist like myself isn't very intrigued by the possibility that we are in a simulation. What difference would it make? Indeed, how would we even know if the simulation was just turned off a few hours ago?

Joe said at July 4, 2011 1:51 PM:

It could just be a sim of a single planet that evolves life. That would require far less computational power than the entire universe. They wouldn't need to be constantly modeling the entire universe, just the parts of it that were being observed at any given time (there's something about the nature of quantum mechanics here).

So yeah, I bet some kid running the simulation puts on a his 3d goggles and then takes over Obama or Brad Pitt or a fighter pilot when he feels like it.

But just imagine how fun it would be to run a 20 minute program, and have the computer spit out 10,000 years of art and literature (as well as science and history and such).

The problem would be that the simulation would come to an end when the computational overhead of the simulated civilization outstripped the computational speed of the computer running the simulation (or slow the simulation down so much that the user would terminate it). Does that mean that once we invent good quantum computers, the simulation ends?

It would be great if some genius could come up with a physical experiment to determine whether we are all in the Matrix.

Dentin said at July 4, 2011 3:02 PM:


One of the more interesting things I've been thinking about is "what kind of computational subtrate is required to simulate the universe?" It turns out that what we know about physics right now actually allows us to make some predictions and tests of the simulating computer. In particular, there are several features of QM and general relativity that do not easily lend themselves to linear or turing computation. General relativity for the moment we have to ignore because we don't have any easy way to construct experiments that involve severely warped spacetime. QM on the other hand provides a much more approachable test: quantum decoherence and entanglement.

The beauty of quantum computing is that it can bring ridiculous resources to bear on a problem in a very small amount of space and time. Consider the staple problem of factoring extremely large numbers; for a sufficiently large number, the number of cycles required to factor it using a turing machine can be made to exceed the processing power available within the entire universe over its entire existence.

Using a quantum algorithm takes a different approach. If we're running on a turing machine, using a quantum algorithm is like making a syscall into the simulator, where you ask the simulator to spawn off a recursive function to compute the result for you. This immediately begs the questions:

1) How much work can you give to the simulator before it bails out;
2) What happens if/when the simulator gives up; and
3) Based on if/when the simulator gives up, what can we learn about the simulator?

Progress is currently being made on 1 and 2, in the form of initial quantum computer research and the 'decoherence problem'. 2 in particular concerns decoherence, as that seems like a reasonable failure mode for the simulator. If the simulator decides it can't handle your problem, it just breaks the entanglement you were using to construct the problem.

The short takeaway is that research on quantum decoherence will be able to tell us something about the type of computational substrate required to simulate the universe. If we discover that there doesn't appear to be a decoherence limit, that quantum systems can be very large while staying entangled and coherent for long periods of time, then odds are good we're not being simulated by a turing machine. Other such 'educated guesses' or upper bounds on the simulating computer can also be made from these kinds of experiments.

Randall Parker said at July 5, 2011 8:02 AM:


If our universe is simulated in a different universe then one possibility is that this other universe is far more complex than our own. It could have more dimensions in space. It could have laws that make quantum mechanics simply by comparison. It could be far larger.


The reason I asked whether sentient beings get simulated as objects is the question of whether the point of the sim is to model intelligences or to model huge physical processes. If the latter then the complexity of a civilization built up in the sim would not increase the computational overhead of the sim. The civilization would be simulated at the subatomic level just as the matter in that civilization was simulated when it was still in the ground.

jb said at July 5, 2011 10:05 AM:

Generally I think we're in a human-centric sim:

Why we're in a sim:
1) We exist at all - the very first civilization in the galaxy capable of interstellar travel should have colonized every planet in the galaxy by now... unless we're the first (or very close), but the galaxy seems much too old for that to be likely.
2) If we can postulate that a sim exists that could model a physical universe like ours, then, given how often such sims could be created vs. real universes, the odds of us being in one of those sims is exceedingly high.

Why we're in a human-centric sim:
1) The fact that we can have this discussion is evidence that we're not terribly far off from creating these sims ourselves. I can justify creating sims for a lot of reasons - historical analysis, economic analysis, wargames, movie and book plots, tamaguchi pets, backstory for a video game, etc.
2) I find a lot of very bland people out there, who seem to have no drive, no purpose, no curiosity. I wonder sometimes if they're just cpu-efficient "filler" objects designed to occupy space so the "real" people won't feel so alone.
3) Arguably, if we're in a representation of the real universe, the aliens that might have populated our world back when we were nothing but cavemen might want to do some 'what if' analysis on us. "what if we had never conquered the human race, how would they have turned out".

Arguments against a human-centric sim:
1) It seems like a waste to build up a whole world in order to simulate some small aspect of it
2) If we're the backstory to a video game or some sort of 'how do humans handle event X', "event X" may be terrifying, and I would rather not have to live through that.
3) If the future humans who are studying us are part of a different universe, either the physics are very different, or the likelihood that they're the first civilization in the galaxy are vanishingly small, in which case they should not exist.
4) Arguably, us being able to think about and discuss the possibility that we're in a sim subverts the idea of a sim, unless the purpose of the sim is to test to see how long it takes us to start assuming we're in a sim.

Arguments against a sim:
1) If it's not a human-centric sim, what's the point at all? A physics simulation of a universe where a "big bang" occurs? That doesn't seem like it would require this kind of fine-tuned analysis

Way out there theories:
1) What if we're in a sim, inside a universe that's itself a sim, inside a sim, inside a sim, repeat 10 trillion times - although I'd guess this would probably not be "human centric" more than a few levels up. the point is - once we get the technology to do it, we are able to create universes at a vastly accelerated rate vs. the physical universe. This would (I presume) be true in any physics. So once the "top" level figures out sufficiently detailed physical simulations, there's no reason to assume that it would stop at one level.

Joe Blow said at July 5, 2011 10:35 AM:

If it's a sim, who is running cybersecurity on the systems? The Red Sox weren't supposed to win the Series. *Ever*. The fact that they did shows that somebody is tampering with the system, and that tampering has destroyed that whole Angry-Boston-Sports-Fan Node of the sim and will probably require a core reboot to fix. Unless the Boston node is just a backup for the frankly more robust Philly algorithm.

werbaz neutron said at July 5, 2011 10:48 AM:

God owns a Mac.

Uniblogger said at July 5, 2011 10:59 AM:

Where is the 'Reset' button?

Celebrim said at July 5, 2011 11:02 AM:

"Are intelligent entities modeled as objects? In other words, are they instantiated and managed as distinct tracked pieces in the simulation? Or is the universe just modeled as huge numbers of subatomic particles and energy?"

1) "I'm not sure that these two things are mutually exclusive. We generally simplify collections of objects into larger discrete entities to simplify things. Clearly however the creators of the sim are capable of apparantly limitless computational power, and with it apparantly limitlesss computational analysis. For all we know, there is a whole other universe which is devoted entirely to acting as a datawarehouse for this universe, allowing the discrete objects of this universe to be catalogued by examining the results of modeling the huge numbers of subatomic particles and energy in this universe."

2) "If intelligences aren't modeled as objects are they at least tracked or studied by whoever is running the sim? Or is the evolution of intelligence in the sim just seen as an uninteresting side effect and irrelevant to the sim's purposes?"

Given what we know of the parameters of the sim, if the development of complex objects wasn't the purpose of the sim then it would be awfully coincidental that it happened.

3) "Is The Big Bang the moment the sim started running? Or did it start long before that point?"

Too little data. The Big Bang creates a hard barrier to the amount we can learn about from before the sim. Much like black holes, they appear to prevent inhabitants of the sim from deducing too much about the starting conditions of the sim.

4) "Or has it been started at a much later point with data loading in to make it look like it started earlier?"

This gives far more credence to some of the young earther arguments than I'm comfortable with, but concievably if all that was interesting about the sim was recent conditions on the earth, then not only might have started at a much later point with data loading, but much of the observable universe might well be simulated at a lower resolution. It's possible we live in a 'Truman Show' bubble a few 10's of thousands of light years across (or possibly even less), with distance in time and space being simulated.

5) "Do the creators of the sim intervene as it runs? Do they patch it?"

Yes. Beyond being a statement of Faith, this is a confidence born out by my understanding of programmers. I may be a small writer of code, but I think I understand something about what sort of mind would want to create these things. There is only a very limited satisfaction in a sim which is completely uninteractive. You don't run a multibillion year simulation without playing with it a bit.

6) "What is the purpose of the sim? Entertainment? Political decision-making? Scientific research?"

Too little data. Traditional assumptions about the sim creators include entertanment, political decision-making, and something akin to reproduction as the goals of the sim creation. I think speaking as a Computer Scientist the one thing that I couldn't accept as a suggestion is that the sim was created accidently in a 'Short Circuit' moment. If Number 5 is alive, it wasn't an accident. Discharges of lightning create complex charred residue; they don't create code.

7) "Were the physical laws of the universe designed to reduce the computational cost of the sim? If so, what aspects of the physical laws were designed to make computation cheaper?"

Other than gravity, almost none of the known forces on the universe have a significant effect beyond a very very short radius. And these effects are so small that they would be usually lost in the rounding errors of quantum mechanics. So beyond a very short radius, the designers can in most cases treat every force but gravity as having neglible effect. In fact, the entire notion of quanta is a huge reduction in computational cost, since it lets you store the universe in a big integer form and run it on a discrete clock. You don't have to compute the space in between the holes because there are no holes. Also, since most of the universe is unenergetic and since most of the universe is empty, computation on most cubes in the matrix can take a short cut. However, the fact that empty space isn't in fact empty suggests that this argument might be spurious.

Kendall said at July 5, 2011 11:03 AM:

One thought for it being likely we are in a sim, is that throughout history we've come to the brink of many huge disasters and managed to get past them.

Only we really didn't - they just re-ran from a certain starting point until we managed to get past whatever issue was present.

Since the people running the sim would naturally try and direct the simulation to reach points on the edge in order to study the results, the existence of so many crises points to an outside influence manufacturing them.

Just food for thought...

patrick said at July 5, 2011 11:04 AM:

Is there a God?

Is the universe just the creation of an extra-universal deity? Suppose it is. Then I've got some questions:

•Are intelligent entities created with free will? In other words, are they created and loved as distinct individuals? Or does God only care about subatomic particles and energy?
•If there is no free will, does God even care? Or are we just an uninteresting side effect and irrelevant to His purposes?
•Is The Big Bang the moment the God created everything? Or did he make it long before that point? Or did he create it later and just make it look like it started earlier?
•Does God act in the world? Does he answer prayers?
•What is our purpose in life? Entertainment? Political decision-making? Scientific research?
•Were the physical laws of the universe designed to make God's job easier? If so, what aspects of the physical laws were designed to make his job easier?

Imagine God's purpose is entertainment or decision-making. Either way, it could be that God actually enters this universe and interacts with some of its intelligent entities. He interacts with His creation for fun. Or interacts in order to test our faith. In the latter case I would expect Him to periodically cleanse the world of sinners to restart with some alteration of what some people say or do.

So what's your (theological) gut feeling? Is there a God? If so, what's He doing?

Patrick C said at July 5, 2011 11:09 AM:

If it's a simulation at the level of physical laws and fundamental particles, it's exceedingly clever - but perhaps there were a few bugs that showed up after it was turned on, such as black holes. At least it's easier to think of billions of solar masses collapsing to a point as just an arithmetic overflow error than an actual physical phenomenon.

Mike said at July 5, 2011 11:10 AM:

Does tne number 42 ring a bell to any of you ?

Got to run now, I just saw throught my window that some weird yellow spaceships are approac

Mark in Florida said at July 5, 2011 11:14 AM:

Maybe not a sim, but a pot of soup. Or a test tube. Or experimental chamber.

If you look at life on Earth and how it has evolved from single cells, it has gotten more intelligent, longer living and more powerful. Extrapolating infinitely, it would end up as omnipotent, omniscient and living forever, which is kind of the definition of most gods. So, god didn't create the universe, the universe, or rather the life in it is evolving into god. We are his ancestors. When he's born maybe he'll bring us all back to celebrate. Well, maybe not all. Leave Manson, Speck, Stalin, Pol Pot, et al to rot.

ajacksonian said at July 5, 2011 11:28 AM:

There is a question of the universe question and Planck time length added to QM. If indeterminancy is to be held then time travel is not possible going backwards: when you know the outcomes of decisions taken at a point in time then you know the outcomes of those quantums and therefore have knowledge of the outcomes of quantum states which is not allowed via QM. Going 'back in time' then is an effort to move oneself into a state where you know the outcomes of the decisions that are made which is not allowed via QM. What you move into is a universe of same index number in time from your starting point with 'you' in it, but it must have a significantly different basis so as to invalidate your knowledge of the outcome of events. From that the place-point in the universe in time you seek to get to cannot be arrived at and the universe puts you into a different universe that removes the certainty of your foreknowledge.

At any given instant the universe is delimited by the minimum time that can have meaningful computational outcomes, which is a limit of Planck time (which is 10^42 planck seconds in each second). That is the smallest known reducible duration of time via physics and allows for the universe to then have QM outcomes that are possible for the next Planck-time duration so long as there is acceptable 'fit' via QM in each possible outcome. As the universe does not pick and choose what the outcomes are, all outcomes are possible. Making decisions is an exercise in free will with various outcomes which you must live with: if you wish to go back in time to render a different decision via any manifestation, then the planck duration just prior to that decision point must vary via QM. What you get is a viariant universe that may have some degree of similarity to that index time you are seeking to go to, but will not allow your future knowledge to be relevant to it. Your decision to go back in time then renders a different universe to which you go into so as to preclude knowledge of quantum level events.

The 'universe' as we know it is thus not of unlimited time duration but of set planck time duration with continuation of consciousness being a creation of the number of universes per second in the way flip cards render motion. Consciousness, then, is discontinuous per universe and the concept of continuity of thought is only held via the continuity of experience across the span of planck-time universes. It is a persistence of vision concept and your consciousness is a creation of the persistance of constantly replacing universes with new index numbers at a very high rate per second. As such the index of 'zero' is the start point in which all possible universes exist but none have been instantiated. The first index number after that now has all possible variants available to it and, indeed, all are carried out. Your experience is that of a number of indecise of a variant based on compatibility with a start variant that allows for your consciousness to exist. There are a high number of nearly infinite universes in which you do not exist with the same index number out from zero, but you experience the passage of time through those indecise in which you exist. If you were able to go backwards in time you might find any number of indices in which all manner of universal configurations obviate your future knowledge. Paradoxes are removed via this mechanism so that removing a grandfather or grandmother does not create a paradox as you are in a variant universe. Do this often enough and you will find yourself in a universe in which backwards time index movement is not allowed. Go back to the zero index point will not find yourself at index point 'zero' but at one of the first index points just after 'zero' as 'zero' contains all possible universes and your ability to exist requires an actual universe derived from all possible ones.

Never forget Planck when talking about QM as it creates the fascinating concept that computational universes are only a subset of all possible universes, just deriving from those infinite universes in which the indecise allows for computational universes to exist. Fun, no?

Inactive42 said at July 5, 2011 11:53 AM:

Well, it's only been about forty years since "Pong". What will video games ("computer simulations") look like a million years from now, keeping in mind that a million years is barely rounding error in the age of our universe (as we currently perceive it)?

David Gobel said at July 5, 2011 12:01 PM:

The arrow of time is detectable via the tug of war between entropy and what I call proplexity. Proplexity is the tendency of our universe to create new entities such as with fusion creating helium etc out of hydrogen. Each layer of emergent complexity (proplexity) creates the platform/foundation for a new scale/layer such that subatomic particles yield atoms, atoms yield molecules, molecules yield chemicals, chemicals yield amino acids etc, all of which are dependent on the earlier scale's stability, completeness and stacked co-dependent complexity. When the complexity stack's altitude arrives at self referential awareness and intervention - aka consciousness, when consciousness is combined with quantum indeterminacy, one gets profound unpredictability and novelty.

The purpose of the universe IMO is therefore to yield surprises and a universe where proplexity overcomes entropy by eventuating in consciousness and then sustainable/successful agape - "sharing and caring for its own sake" which would be something like psychosuperconduction. The greatest surprise hoped for or wagered against by the "viewship" of this simulation is whether the emergence of agape, the antithesis of entropy can happen.

The opposite of love is not hate - it is selfishness.

Nate said at July 5, 2011 12:04 PM:

Interesting questions...and some that have been recently on my mind, as well.

Is anyone here familiar with Greg Egan's sci-fi book, Diaspora? Wikipedia has a good summary of it http://en.wikipedia.org/wiki/Diaspora_(novel)
The ending, IIRC, is a little depressing and nihilistic...but somewhat hard to argue with. What would YOU do, if you lived FOREVER...and I mean
Sagans (yes, that's Billions and Billions!) of years? My thinking: maybe I'd temporarily suspend part of my personality / knowledge, and then
live as someone else in a different context? Between "lives", I'd integrate the experience from that life with all the others that I had lived.
There are perhaps innumerable variations on existence...and each time, living a whole life from birth to death would bring me a little closer to Humanity.

On a completely different line of thinking... jb referred to Fermi's Paradox, above. Although I still find it hard to believe, I'll admit that
it is possible that the odds of life evolving to intelligent manipulation of the environment is so rare that we are essentially alone. In such case,
seeking an alien intelligence - an entity that is clearly intelligent, but one with a wholly different perspective - might best be accomplished by
evolution within a simulation. In this case how would we KNOW that our simulation produced something intelligent, and autonomous? Not something merely
reactive, but something with *will*? In more concrete terms, software does what it's told to do (excepting bugs, of course). A more
apt Turing Test might be something along the lines of when the AI says, "Hey...this was a great conversation, but I have some other stuff I'd like to
do...so...ummm....give me a call sometime and bye for now." Poetically...maybe Adam wasn't the first homo sapien - but the first to exhibit defiance -
and thereby demonstrating a will that is significantly independent of the Creator.

As to the more straightforward questions of computational complexity. I think our understanding of software is far too primitive to expect reasonable answers.
However, I intuitively suspect that the quantum mechanical nature of the universe is for *reducing* computational complexity. So, on that notion, I give +1 to Celebrim's post, above.
To further elaborate on this idea, I also add that it's curious that space-time seems to have a finite density of information. There are only so many questions
one can ask about a volume of space-time before the answers become irrelevant (i.e. Planck length). Although this doesn't necessarily imply that we are living in a computer simulation,
the limits on information density would be consistent with a digital universe.

Dan Morgan said at July 5, 2011 12:08 PM:

I happen to have a couple of inside scoops on all of this.

First, the guys running the sim think they are big shots, but little do they know that they are in a sim too. In fact, the reason they are being simulated is to see how well and quickly they could design the sim we live in. That is their sole lowly purpose. It sucks being them.

Second, the good news is that when the sim is turned off, it takes time to wind down. Our corner of the sim resides on a remote sector of the clunky harddrive, and with the harddrive's intertia, even when they pull the plug we will be okay for awhile. We will see a big wall of black holes coming toward us as other sectors of the hard drive get erased during its wind down, but that is great because then we will know we have a couple of weeks to quit a jobs, party like mad, and do lots random breeding.

Tranquil.Night said at July 5, 2011 12:16 PM:

- What if the simulation is specifically an attempt to share the experiences and knowledge of joy, serenity, and love with others.

- What if the Programmer couldn't design a simulation of Order without inputting a variable of Randomness and Chaos, just as there could be no real understanding of Growth and Renewal without an element of Destruction.

- What if the Programmer tried to Protect the most precious creations the Laws of Nature had yet produced (sentient life) from the idea of using their superior intelligence to harm rather than build - but seeing as His greatest gift was their ability to act independent from instinctive behavior - he couldn't.

- What if the Programmer, saddened by the rise of great empires of human corruption and suppression of the innocent, realized that the only way humanity would rise up against those who through idolatry of the self would pursue power through violence and tyranny, is if they knew that a path of virtue lie open for every living individual to pursue that would result in the conquering of even the most brutal and seemingly lonely deaths. Maybe the Programmer patched himself into the simulation and left an actual record espousing this very idea through word and action.

- Perhaps we are the patchers meant to pursue a more perfect universe. And perhaps 235 years ago a government finally came into being that recognized and went on to vindicate these very fundamental principles.

- What if we're on the verge of a whole new understanding of the simulation and the Programmer's intent. And what if we've still only just begun...

Let not your spirit be troubled. It is as much about the journey as the final destination.

McGehee said at July 5, 2011 12:27 PM:

I know I'm not a computer simulation because if I were I would have gone BSOD years ago.

Carl Pham said at July 5, 2011 12:49 PM:

If the "universe" were a simulation, there would be no need to simulate any more than the interior processes of a single intelligent viewpoint. Accordingly, if it is, none of you nor indeed any exterior object exist. Only my conscious processes exist, and only when I am awake. (It is of course possible that there is no time at all when I am asleep, there are merely discontinuities in my conscious experience which I am trained to interpret as "sleep," and it is equally possible that the time when I am asleep lasts milliseconds or aeons.) There are no "laws of physics," for example, there are just plausible reports of such that reach my eyes and ears.

Really, the hypothesis that the universe is a simulation is not distinct from solipsism or some other philosophical reductio ad absurdum. What people who haven't done simulations don't always understand is that there is no point at all to doing simulations that are fully realistic. It takes much, much longer than simply doing a measurement of whatever it is you want to know. Simulations are only done of simplified models of more complex reality, usually to measure how much simplification can be done without disturbing a particular observational fact, so that we can identify the important and less important contributions to it. Hence if the universe were a simulation, it is certainly a simpler -- much simpler -- object than it seems. Furthemore, I know the universe contains at least once experience of an intelligent, aware observer (mine), and that would not exist unless it were an essential goal of the simulation. (It is obviously not necessary to have intelligent observers to have a functioning objective universe.) Since no objective reality outside my experience is necessary, it follows that a careful economic simulator would not have programmed them.

Lance said at July 5, 2011 1:40 PM:

More importantly, does this blog post constitute the "sim" becoming self-aware, and if so how long until I get my own robot?

Jay said at July 5, 2011 2:02 PM:

Isaac Asimov answered most of your questions in 1956


Warren Bonesteel said at July 5, 2011 2:15 PM:

I often wonder...how many of you are non-player characters?

Phil said at July 5, 2011 3:22 PM:

I was going to add a germane comment but then I realized you already knew it.

Alexa said at July 5, 2011 6:44 PM:

Carl: "Simulations are only done of simplified models of more complex reality ... Hence if the universe were a simulation, it is certainly a simpler -- much simpler -- object than it seems."

No, it need only be a much simpler model of the sim-builders' universe.

Brett_McS said at July 5, 2011 7:31 PM:

If the universe is itself the computer (like the Earth in HHGTTG) does this answer the question in the positive or the negative?

Phelps said at July 5, 2011 10:18 PM:

If you believe the Old Testament, there was an extensive debugging / beta period with frequent and significant modifications and tweaking by the dev, with a slow tapering off of direct involvement. I would say we are in full release now.

Phelps said at July 5, 2011 10:23 PM:
Were the physical laws of the universe designed to reduce the computational cost of the sim? If so, what aspects of the physical laws were designed to make computation cheaper?

Wave functions. They are probabilities (a lookup table of percentages) until they are observed (interact with a significant object.) Once they are observed, then they get specific data loaded in based on a random factor based on the lookup table. This would allow the simulation of massive things like stars as just "stars" until specific parts of it need significant interaction. It's memory saving.

Really, all of quantum physics suggests memory saving and dynamic loading.

Phelps said at July 5, 2011 10:27 PM:
What people who haven't done simulations don't always understand is that there is no point at all to doing simulations that are fully realistic. It takes much, much longer than simply doing a measurement of whatever it is you want to know.

Not true. Physicists do models of multiple dimensional spaces much more complex than the traditional four because the dimensions they want to explore cannot be measured by our technology.

Dentin said at July 6, 2011 10:32 AM:


My point was not so much to speculate or give my opinion as to show that there are actual physical experiments and observations that one can perform to determine the limits of the simulating computer/process.

Observations of the known universe provide information on minimum levels of data storage and processing power. QM and relativity experiments have the potential to vastly raise the processing power limit beyond our current linear estimates, and may be able to tell us something much deeper about the simulating computer.

All of this is vastly better than the rampant speculation I see in most of the other comments. Speculation about the motives of the simulation writers is just that: speculation. But setting lower limits on the type of simulation we are in can absolutely be done.

MichaelG said at July 6, 2011 11:28 AM:

If we had the capability, we might simulate the early Earth and look at the development of life. We might vary parameters to see what other kinds of life could arise.

An advanced AI might be interested in the origins of artificial intelligence. It might run simulations of those years up to the emergence of AI on Earth. This world is one of those simulations, designed to see exactly what conditions led to the origin of AI, and what other types of AI might have arisen.

The only people simulated are the ones working on AI. The rest are not important.

Once the AI emerges, the simulation ends, and the people are thrown away.

malclave said at July 6, 2011 9:30 PM:

Dear devs:

The "Politician" class need to be nerfed.

Botec said at July 7, 2011 6:03 AM:

If it is true that we live in a simulation and that the only humans fully simulated are those working on AI and the rest of us are p-zombies, then anyone who actually works on AI who moves to an unrelated field should fear that their consciousness will be summarily terminated, which is probably a great incentive to keep working on it.

However, I know I am not a p-zombie (though of course cannot prove it to anyone else), and know I will never work on AI, so I can reject this specific claim. But a similar argument applies for everyone who thinks that any aspect of their own life might be the property of interest to a simulation's external observers.

Widespread belief in the simulation of only a limited subset of humanity could lead to decision-making paralysis, lest someone who knows they are not a p-zombie inadvertently ceases to be interesting to the simulators. If I'm a window cleaner who fancies becoming a zookeeper, will I effectively sign my own death warrant by changing my career?

Since I am astonishingly uninteresting in almost every respect and cannot think why anyone would bother to simulate me, I assume if we are in a simulation at all, then nearly everyone is simulated. Or it is possible that the question to be answered is 'How do uninteresting people cope with their lives?'

Randall Parker said at July 7, 2011 7:09 PM:

Carl Pham takes the view that a universe sim is only important to serve as an AI sim:

If the "universe" were a simulation, there would be no need to simulate any more than the interior processes of a single intelligent viewpoint.

But why? What if the runner(s) of the simulator are not interested in simulating intelligence? I can think of many reasons to run a sim other than to simulate intelligence.


Maybe the universe is a test of how uninteresting people interact with interesting people. Maybe in the real universe everyone is interesting and they want to find out what happens when some people are unbelievably dull.

BTW, I like the way the sim writer decided to have you claim that you are not a p-zombie. The sim watchers are all laughing at that one.


Knowledge about limits and contours of the simulation tells us nothing about the world that the sim runs in.

3d Space said at July 8, 2011 3:32 AM:

your probable answer here awaits


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