what if we are just a computer simulation?

[jdsutton]

It service as great setup for a sci-fi book or movie, but to use it to explain the real world requires a whole lot of faith.

Hopefully not for long:

http://www.wired.co.uk/news/archive/2012-10/11/universe-computer-simulation

http://www.technologyreview.com/view/429561/the-measurement-that-would-reveal-the-universe-as-a-computer-simulation/

[Albert VDS]

Let's say we do find out the universe works like a computer processing information.

That still doesn't mean we live in a computer simulation, because you are still filling in the blanks.

It's like that "Ancient Alien" meme:

The universe processes information, therefore computer simulation.

What also makes it a bit funny is that it's like: "Hey our simulation looks like the real world, so it must be a simulation too!"

Edited July 23, 2013 by Albert VDS

[MBobrik]

what if we are just a computer simulation?

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Nothing. Business as usual.

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It got basically no consequences down there. Simulated flame burns simulated flesh as good as the real thing. simulated animal deprived of simulated food will die a realistically simulated starving death. discovery of the formulae the simulation uses to compute simulated atoms is as important as discovering those in real world ... etc. Even the eventual meddling of its creators has a real world counterpart, because even the real universe might be just a part of a larger thing inhabited with meddlesome intelligences ...

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The only difference is, that in a simulation, we might accidentally find a bug that either allows us to take control of the underlying OS, or crash the system and wipe ourselves out of existence (not really, just cause the operators to restore the simulation database from backup and fix the bug).

[Dunbaratu]

Secondly, I recall seeing a quote from a someone who was seriously looking in to the computer simulation theory, and he stated that the universe can have created no more than 10^120 bits of data, which is quite reasonable for a super computer to do AFAIK.

There's a basic principle at work here, very similar to the stopping problem (that a computer program cannot be made that detects whether another computer program has an infinite loop in it, because the act of checking if it's infinite would itself take infinitely long if it is in fact an infinite loop. You can determine that it *has* stopped, but not whether or not it *will* stop later if it hasn't already. if you're a computer program. you can't analyze another program without basically running it yourself simulating what the CPU does, which means you get stuck too in an infinite loop while trying to analyze a program with an infinite loop.).

The principle here is that it is utterly impossible to track an amount of data as large as the entire universe without a computer that itself has at least as much material as the entire universe. Just trying to store the state of the universe in a memory bank requires numbers to keep track of all the particles... and those numbers have to be stored on something... like more particles. That's why you need a computer larger than the universe to simulate the universe accurately.

So the idea that the total amount of data needed to track the universe can fit in one of the supercomputers we've already invented today.... is literally impossible. Any universe we simulate will necessarily have to contain fewer particles than our own universe or else the computer to do the simulation wouldn't FIT in our universe.

[tomf]

If you were running a simulated universe you wouldn't have to fully simulate every particle. A rock that no-one is looking at with a microscope can just be a surface, a collision mesh etc. If someone comes along with a microscope you will just have to fill in some details. For the simplest simulation you only simulate one consciousness fully and fake the rest. A weird kind of solipsism - "I'm not real but I'm the only real simulated person".

If you believe in inevitable technological progress then you can argue that statistically we must be a simulation. Once a civilization advances enough to run simulations of consciousness then they are bound to run lots of them, which will in turn evolve enough to run their own simulations. You have a boundless number of nested simulated universes and only one reality. The chance that we are in the real one is vanishing.

[Monkeh]

If you were running a simulated universe you wouldn't have to fully simulate every particle. A rock that no-one is looking at with a microscope can just be a surface, a collision mesh etc. If someone comes along with a microscope you will just have to fill in some details. For the simplest simulation you only simulate one consciousness fully and fake the rest. A weird kind of solipsism - "I'm not real but I'm the only real simulated person".

If you believe in inevitable technological progress then you can argue that statistically we must be a simulation. Once a civilization advances enough to run simulations of consciousness then they are bound to run lots of them, which will in turn evolve enough to run their own simulations. You have a boundless number of nested simulated universes and only one reality. The chance that we are in the real one is vanishing.

Just a surface wouldn't have the gravity of a proper rock, it wouldn't bend light from distant galaxies, we wouldn't have stars whizzing around super massive black holes at the centre of the galaxy at ridiculous speeds if there was only a non-visible surface there to intract with.

To suggest this could be added as we observe would require time travel, you know, speed of light being finite and all, so I'm afraid that theory doesn't work for me.

Our universe appears geared up to make black holes. In time, the only thing this universe will consist of is super-super-super massive black holes decaying slowly away through Hawking radiation. Our universe is a power plant for black hole mining super beings that haven't even noticed these sub microscopic specks of carbon scrabbling round in a very thin layer of gas surounding a miniscule dustball orbiting a very slightly less miniscule gas ball.

That's right folks, were just a power station for extra universal beings.

[tomf]

Put a center of gravity in the center of the rock. Or better still if someone starts looking for the light bending affects of a rock you just create the photons they would expect to see appear in the eye of the observer - no time travel required.

[Cheebsta]

If you were running a simulated universe you wouldn't have to fully simulate every particle. A rock that no-one is looking at with a microscope can just be a surface, a collision mesh etc. If someone comes along with a microscope you will just have to fill in some details. For the simplest simulation you only simulate one consciousness fully and fake the rest. A weird kind of solipsism - "I'm not real but I'm the only real simulated person".

You are probably aware, but this is actually an accepted quantum theory in a sense. Objects are just possibilities, observation allows, or forces, them to take shape. Making the goofy part how exactly everything takes the same shape for all of us. Almost like a universal non-local regulatory consciousness at work behind the scenes.

Our universe also has at least one redundancy scheme. Each individual person exists physically, but there is also an instance of that person in their own mind, and in the mind of every person they meet. All these instances represent the same physical body, but can all also vary wildly from that, and each other. I am pretty sure this concept is what drove the guy who made Neon Genesis Evangelion crazy, lol.

[Monkeh]

Put a center of gravity in the center of the rock. Or better still if someone starts looking for the light bending affects of a rock you just create the photons they would expect to see appear in the eye of the observer - no time travel required.

No time travel, just a small level of omnipotence. I find this to be equally unlikely. Especialy when we're the cosmological equivalent of extremophile bacteria clinging on to a tiny speck of Uranum in the reactor of a nuclear power plant.

[Cronos988]

You are probably aware, but this is actually an accepted quantum theory in a sense. Objects are just possibilities, observation allows, or forces, them to take shape. Making the goofy part how exactly everything takes the same shape for all of us. Almost like a universal non-local regulatory consciousness at work behind the scenes.

That doesn't sound correct to me, though I have only very limited knowledge of quatuum physics. Anything as big as a rock will have it's potentials locked into that specific shape. Only single, unrestricted particles exist as possibillities. As soon as they get together, their waveforms collapse into a single possibility. It is still possible for objects to randomly change completely, but the likelyhood of that is so low that statistically it won't even happen once in the lifetime of the universe.

Our universe also has at least one redundancy scheme. Each individual person exists physically, but there is also an instance of that person in their own mind, and in the mind of every person they meet. All these instances represent the same physical body, but can all also vary wildly from that, and each other. I am pretty sure this concept is what drove the guy who made Neon Genesis Evangelion crazy, lol.

The differentiation between the "physical" person and the person inside one's head isn't exactly unproblematic. And every instance of us inside the consciousness of other people isn't correct. Those are all only partial, sometimes completely incorrect, versions. One could argue that fictional characters do indeed "exist" in hundreds of very similar instances across the readership. But that is completely off topic now .

Put a center of gravity in the center of the rock. Or better still if someone starts looking for the light bending affects of a rock you just create the photons they would expect to see appear in the eye of the observer - no time travel required.

You still need the entire data, though. And depending on the observer, you will need to simulate not only his consciousness, but every natural phenomenon he comes into contact with. If your simulated consciousness is an astrophysicist, that might be a lot of simulation to run. Anyways, the idea of only simulating a single consciousness seems theoretically possible. We have absolutely no idea how hard it is to simulate consciousness, but we might actually find out in the not so distant future. If the programmers of our simulation allowed it, that is.

[Cheebsta]

That doesn't sound correct to me, though I have only very limited knowledge of quatuum physics. Anything as big as a rock will have it's potentials locked into that specific shape. Only single, unrestricted particles exist as possibillities. As soon as they get together, their waveforms collapse into a single possibility. It is still possible for objects to randomly change completely, but the likelyhood of that is so low that statistically it won't even happen once in the lifetime of the universe.

What does matter act as, a wave, or a particle? And what happens when I smash the rock? Or when a tree falls down and rots away... That's fairly complete change, and I've personally seen it happen several times in my life... I must be really old >.>

[MBobrik]

For the simplest simulation you only simulate one consciousness fully and fake the rest.

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thus making the whole humbug prone to being blown upon first complex debate about something.

[jdsutton]

You still need the entire data, though.

The full data for an object could be stored in the equivalent of a hard drive, only being loaded into the RAM equivalent and fully simulated by the program while it was being observed.

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thus making the whole humbug prone to being blown upon first complex debate about something.

Consciousness isn't necessarily equivalent to intelligence. There could exist one single entity that actually experiences the universe, while all other intelligence might be unconscious arrangements of particles or simple variations upon a single algorithm.

[Albert VDS]

The full data for an object could be stored in the equivalent of a hard drive, only being loaded into the RAM equivalent and fully simulated by the program while it was being observed.

No matter where you keep the data, you still need to a bigger universe than the one you are simulating.

It's like a book, it doesn't change size because you are only reading 1 page at a time.

[magnemoe]

Just a surface wouldn't have the gravity of a proper rock, it wouldn't bend light from distant galaxies, we wouldn't have stars whizzing around super massive black holes at the centre of the galaxy at ridiculous speeds if there was only a non-visible surface there to intract with.

To suggest this could be added as we observe would require time travel, you know, speed of light being finite and all, so I'm afraid that theory doesn't work for me.

Would it really, think like how computer game graphic work. You only render the part you see, not things behind your character or behind walls.

You operate outside the universe so if somebody look at an galaxy with an telescope you will generate the image shown.

Yes you would get an serious savegame bloating as you would have to remember all of this things so you can show the same image to other.

On the other hand I find this idea extremely little convincing. It would also be impossible to prove, as in prove it exist an omnipotent god who do not want to show himself.

[Cheebsta]

No matter where you keep the data, you still need to a bigger universe than the one you are simulating.

It's like a book, it doesn't change size because you are only reading 1 page at a time.

Space doesn't even have to be a thing outside the simulation, neither does any other notion relative to the simulation, like size. This is the primary reason why a) there is nothing you can do about it and there is nothing you can prove about it.

[jdsutton]

Yep, we can't really make any assumptions about the limitations of external universes when we currently have no way of observing them. We shouldn't assume that our universe is particularly complex, either. For all we know, simulating something like this could be a walk in the park in a different dimension.

[Omicron314]

I find this an intriguing yet scary thought. Knowing that you are completely at the mercy of extraterrestrial beings that are smarter and more real than you are. But it's a nice feeling, as well. You do not actually exist by the Programmers' (that's what I am going to call them for now) standards, but neither does anybody else. I wonder if we build a large enough space station we can lag the system...?

This would be an interesting thing to teach children in school, but I have no doubt it will be more contentious than evolution for the proceeding centuries. Too bad, I guess.

[Albert VDS]

Space doesn't even have to be a thing outside the simulation, neither does any other notion relative to the simulation, like size. This is the primary reason why a) there is nothing you can do about it and there is nothing you can prove about it.

Neither does time, if it's compressed or stretched, or the which way and how many directions in flows.

Or what about dimensions? We could add 10, maybe 200, or let's say 10^40. That could bring down the space requirement needed to simulated our universe.

That could even make it possible for the entity who's simulating our universe to simulated a multiverse right in his own home network.

We could say a lot of things which sound solid and reasonable, but without prove it just crumbles down to being as silly as some flying spaghetti monster up in the sky.

Edited July 23, 2013 by Albert VDS

[Cheebsta]

Lack of proof is proof of nothing.

[jdsutton]

There's a "what if" in the title of this thread, so we should all expect it to be mostly speculation. There's nothing wrong with entertaining interesting thoughts.

[CleverClothe]

I highly recommend Stephen Baxter's novels by the way, most interesting. Most relevant to you lovely Kerbal enthusiasts would be 'Titan' and 'Voyage'. All about planning and executing manned missions to Mars and Titan. Fascinating stuff.

I LOVED Titan. Now I have a very visceral image whenever someone mentions Tholins. So I will have to check out Voyage.

[3_bit]

If so, wouldn't thinking about paradoxes kill us? Even if we were a simulation, who really cares? We're still sentient life forms. Nothing really changes except how we perceive our home. if we were people might start blaming those who created us for all of their problems, no doubt.

[Lanfranc]

Somewhat relevant (and by PBS Ideas Channel, so also awesome):

Edited July 24, 2013 by Lanfranc

[Monkeh]

Would it really, think like how computer game graphic work. You only render the part you see, not things behind your character or behind walls.

You operate outside the universe so if somebody look at an galaxy with an telescope you will generate the image shown.

Yes you would get an serious savegame bloating as you would have to remember all of this things so you can show the same image to other.

On the other hand I find this idea extremely little convincing. It would also be impossible to prove, as in prove it exist an omnipotent god who do not want to show himself.

The universe does not work like a computer game. If I look away from one part of the night sky the stars still have to orbit, the galaxies still need to rush away from each other, all these things still need to be computed and results applied for when I look back.

A game can render only the parts that you look at because normally there's nothing happening in the bits you don't see. NPC's don't carry on walking and talking, bosses don't sit playing poker with their minions until you turn up, it's all scripted for when you get to a certain place in the terrain or time frame. So very, very different it's a silly analogy, sorry.

Edited July 25, 2013 by Monkeh