Is our Universe Simulatable?

[Opiop]

That was just offensive Drenius. Do you know how the universe works? No? Then don't tell me I don't either.

[SimonH]

Thinking about it some more...
Some of the most powerful computer systems are simulating the weather on earth with a pretty good degree of (short-term) accuracy. As CPUs get ever more powerful, it's reasonable to assume that models (rather than a simulations) will be made of the universe. That could get interesting! In the same way that our weather models showed the el nino current to be highly significant to our climate, maybe universe models will show us things we never guessed at? Wormholes maybe?

[Cero]

@Cero:
No, not the universe. Some physicists believe they have a pretty good idea of what the universe is and where it came from.
Reality. The existence of the universe requires at least one thing: Existence.
Not time or space but pure, meaningless existence. This is a paradox.

You are right, of course. However thats not a paradox just something beyond our grasp.
Our universe is the only amount of reality we know, there might be more, that universe is expanding "into" existence a room of existence if you will.
why that room is there or how is a question but not a paradox.
the universe could also turn non existing space, negative reality if you will into positive while expanding, during that process
point is yeah, we dont know but I dont see the paradox. A paradox implies that assumption A and B are both right but cancel each other out. like the drake equation
I mean our definitions of reality and existence are getting kinda muddy because we are wandering into philosophy since we are not that far in science.

Games published by our own members! Check 'em out!

[Drenius]

@opiop: You are right. You dont seem to have got what I mean, but probably because I explained it bad. Let it rest in peace please.

@SimonH: Nice to see somebody back on topic. (Edit: Cero too.)

[DrZoidberg]

Let's assume that we had a simulated universe running on a computer. A fully deterministic universe without any quantum randomness.
We have an initial state S and a function f that transforms the current state into a future state. f contains therefore the complete laws of physics of that universe.
That means any event that ever happens is fully determined by S and f alone and completely independant of the computer.
One question here is - what happens when intelligent beings evolve in that simulation? They would not be able to determine if they are simulated or not.
Again - anything that happens depends on S and f alone. So they couldn't possibly build an instrument that measures anything that isn't derived from S or f like for example the computer or the outside world.
The paradoxical thing about this is - Even if they somehow came to the believe that they are simulated, they wouldn't be able to tell whether the simulation is running or not, or whether it ever run at all. Because that information is not contained in either S or f.

[ctomni231]

It is certainly a very deep question.

Currently, for us to create semi-accurate simulations, we have to understand all the parts of the object we are simulating. Since we do not actually understand all the parts of the universe, I'd say that currently making a simulation is just plain impossible. So, currently, I believe it is impossible for human beings to create a valid simulation of the universe. (Maybe parts of the universe, but not as a whole.)

If we expand this question to the future...

Understanding of the universe and all its parts will completely remove the need for a simulation. If we knew how to create our own planets, our own stars, etc. Chances are we would just choose a section of the universe and create a real-life simulation on it. There would be no need to recreate it on binary when we can just use the universe as our playing ground.

Honestly, I believe the human race will cease to exist by the time this is figured out. Computers, no matter how advanced they are, have a weakness that they can only be represented in a series of numerical bytes. Recreating something like the universe on a machine with limitations only limits what you'll be able to create.

As far as we know, the universe is still expanding. Even if we dedicated all our current computing power to this, it probably still wouldn't be enough ...

[nerb]

Is it possible?

Without getting too philosophical:

I believe yes, theoretically it could be. If you consider that the universe and everything within it is the result of interaction between particles (of some description) and forces, then yes it could be modelled. Providing that you know the initial state, and precisely how everything interacts.

Practically, no it couldn't. We don't have the computational power, nor complete enough understanding of the 'system' to do it.

Getting very philosophical:

We have an initial state S and a function f that transforms the current state into a future state. f contains therefore the complete laws of physics of that universe.

Don't you find this very, very interesting? This leads me towards the belief that choice is an illusion, and that whatever has happened in the past was always going to happen, given the current values of 'S' and 'f' of the universe in which we currently exist. Not in a 'predetermined fate' kind of way (although I guess it is related), but in a 'we have multiple choices, but we were always going to make the choice that we made' kind of way.

I once saw it explained with a snooker analogy in some strange popular science video. If you could set up a snooker game so that the balls are in the exact same position at the start of the game, the environmental conditions are the exact same, and you break with the exact same application of force, then the balls will move the exact same way each and every time. I.e. the outcome is the same, given the exact same initial state and influences. Could this not then be extended to the universe? If you could 'reset' the universe to time = 0, give it the exact same state as our current universe, then let it run its course again, there is no reason to suspect that the outcome would be any different to now. I.e. I'd still be sitting here and writing this post, you would be sitting here reading it, I would've had the same thing for lunch, so on and so forth.

...interesting stuff...

[Roquen]

Never: http://www.java-gaming.org/topics/orders-of-magnitude/27917/view.html

[Riven]

Some people seem to assume you have to simulate the universe in realtime, before it is considered a true simulation.

Let's assume we have a universe consisting of 2⁶¹⁴ bodies.

Now we create a simulator that can handle 1 body-interaction per second. It would take 2¹²²⁷ seconds to advance to the next state, so it would take roughly 2¹²⁷¹ seconds to simulate 1 second. Now we set the initial state to be our current universe. Although it will take eons to simulate one tick (a planck time), any 'human' (an arbitrary group of particles in our simulation), would live out their life exactly the same as how they would in our universe.

Given limited (not unlimited!) computing power and endless time, where the simulator would run outside of our universe, it is trivial to simulate a universe, and there is no reason to exclude the possibility that our universe is such a extraordinarily slow running simulation.

[Roquen]

My response was for can "we" simulate our universe.  Is our universe a simulation?  Possible.  The earth might be flat (infinitely more probable) or we might live in "The Matrix".

For fun: http://arxiv.org/abs/quant-ph/0110141

Games published by our own members! Check 'em out!

[Opiop]

I found this interesting couple of paragraphs:

Everything in the universe is quantifiable in some way. Even life is quantifiable, despite medicine’s long reputation as an “inexact science.” The Human Genome Project, which sequenced the chemical base pairs that make up human DNA, was solved using computers. All the secrets of the universe are solved using math. In fact, we can explain the universe better using math than we can with words.

If everything is mathematical, everything could be broken down to binary code. So if computers and their data progress enough, could a functional human be created using the genome sequence inside a computer? And if you can build one being, mightn’t you build a whole world of them?

Really interesting to think about. Everything is truly based off of math, so it could be feasible to think we are in fact in a simulation. It also goes on to talk about "bugs in the code". Such as in the movie, The Matrix, where deja vu is just the simulation "skipping". There are some freak occurrences in everyday life that could be " bugs".

Weird.

[Drenius]

Did this pot before, it was moved. I cut everything opiop related now.

At the end, the universe we live in is what it is. We can understand parts of what it is and why it is, but there will always remain questions.
We could simulate it (although not yet), but just approximately and never 100% accurate.

My response was for can "we" simulate our universe.  Is our universe a simulation?  Possible.  The earth might be flat (infinitely more probable) or we might live in "The Matrix".

Everything depends on definition. Even "The Matrix" asks "What is 'real'?"

[Roquen]

Forget "What's real?"  Better questions are "What's feasible?" and "How probable?"  It's impossible to simulate our universe in some other universe that obeys the same rules as our own.  The scales are too large and you have to bend over backwards to make the numbers work out.  So it would have to be in a universe vastly more complex than our own.

[lcass]

to store and simulate exactly you would require more than one particle of memory per particle infact to simulate one particle to the exact specification of the universe you would require a large processing power and at minimum a megabyte of memory

[Cero]

It's impossible to simulate our universe in some other universe that obeys the same rules as our own.  The scales are too large and you have to bend over backwards to make the numbers work out.  So it would have to be in a universe vastly more complex than our own.

That is an interesting notion. I'm not sure it's true... it might be. I do recall that many of those science fiction stories were like that, that the super universe has more dimensions...

I dunno, quantum computing with quantum entanglement and everything - size should not be an issue

Btw that brings up a 2 classic questions:
1) can beings of lesser dimensions exist in a universe with more dimensions ?
2) Is there any chance of inhabitants of a simulation to exit out anyway ?

Coincidentally the main topic in the game I am working on is simulated reality

[lcass]

I dont think you fully understand what quantum computing does , quantum computing does not give you more memory it just allows you to perform a specific function (similar to for functions) very quickly and output a single result. It does not make standard processing any faster and doesnt support more memory. Quantum entanglement technically reduces the amount of memory avaliable because you are binding one particle to another making them "the same" of course in a very stretched out term.

[KevinWorkman]

This question has been asked many times before by philosophers, futurists, and sophomore-year college students. It doesn't have a "real" answer, but you can read about all the different schools of thought on it here: http://en.wikipedia.org/wiki/Determinism

[matheus23]

My god. I just got on JGO to find two pages of discussion in front of me, this topic is really hot!

Have you seen this? (Maybe it sparked this topic!) https://www.youtube.com/watch?v=YOxDb_BbXzU

Haha, yes. I have seen it, but it was some weeks ago. The Idea to post this question here was born because I saw your profile picture

The scales are too large and you have to bend over backwards to make the numbers work out.  So it would have to be in a universe vastly more complex than our own.

I don't think so. Remember what Riven said: We never said we would simulate the universe in real time. The other universe in which our universe is simulated might 'run' much faster than ours.  We couldn't notice

Logically, you can't simulate the universe.
If you managed to make a simulator, then the universe would be different - it'd have the simulator in it. You'd have to simulate the universe with the simulator in it simulating the universe which had in it the simulator simulating the simulator simulating the universe... and so on ad infinitum...

Quite an interesting thought but it's not quite true. Remember what Riven said, again.
We build our simulator. It runs 1/10 of a year of the universe every year (in our universe).
The simulated universe builds a simulator. It run's at the same speed. But in relation to our universe it runs with (1/10 * 1/10) the speed. It takes 10 years in the simulated universe to simulate one year in the simulated simulated universe. And it takes 100 years in our universe to simulate the 10 years in the simulated universe.

Meh. Words... Ewww.

1. Universe builds simulator. Time in simulator to time in our world: 1:10
2. Simulated universe builds simulator. Time in simulated simulated universe to time in our world: 1:100
3. Layer 3 universe builds simulator. Layer 4 universe in comparison to our world: 1:1000
And so on...


I'm asking myself also a little about: What is life? (philosophical, again)
If we simulate a human in a computer. It's thinking. It maybe learns to talk and maybe even starts to think about morality. I assume many people would argue it's not a living person, because he/she is simulated in a computer. Technically only bits and bytes. I think that's a little naive, but yeah...

Quite cool that this topic is so hot. These are questions I've asked myself a lot and it's nice to see I'm not the only one

[Cero]

I dont think you fully understand what quantum computing does , quantum computing does not give you more memory it just allows you to perform a specific function (similar to for functions) very quickly and output a single result. It does not make standard processing any faster and doesnt support more memory. Quantum entanglement technically reduces the amount of memory avaliable because you are binding one particle to another making them "the same" of course in a very stretched out term.

One problem about computing is that light is to slow and makes a cpu too hot. quantum entanglement would remedy that.
More memory is not needed imho.
If you build a death star sized object in space, with the technology we are going to have in 3000 years,considering 64gb micro SD so exist today, its a number so high I dont even wanna think about it

[KevinWorkman]

You might also be interested in reading about the technological singularity: http://en.wikipedia.org/wiki/Technological_singularity

[lcass]

I dont think you fully understand what quantum computing does , quantum computing does not give you more memory it just allows you to perform a specific function (similar to for functions) very quickly and output a single result. It does not make standard processing any faster and doesnt support more memory. Quantum entanglement technically reduces the amount of memory avaliable because you are binding one particle to another making them "the same" of course in a very stretched out term.

One problem about computing is that light is to slow and makes a cpu too hot. quantum entanglement would remedy that.
More memory is not needed imho.
If you build a death star sized object in space, with the technology we are going to have in 3000 years,considering 64gb micro SD so exist today, its a number so high I dont even wanna think about it

you still are not getting it quantum computing is using quantum entanglement , light is how all matter communicates and is the maximum speed (in non virtual particles). you physically cannot go faster than it without going really deep into horrifically complicated quantum physics. , just to point out aswell light is heat. you cannot perform any function other than data transfer with quantum entanglement, its useful for interstella transmission but is basically useless performing functions faster than standard electronics.

[Riven]

Offtopic:

just to point out aswell light is heat

AFAIK 'heat' is not really a thing. We perceive vibration as heat, but vibration is nothing more than a group of atoms that get in eachother's way, bouncing against eachother while trying to move in a straight line. A single atom can't vibrate (without external forces), because there is nothing to bounce off of, so a single atom can't be cold or hot: it only has a certain velocity, and combined with its mass, it results in kinetic energy.

So saying 'light is heat' is a bit off: light is a form of energy, just like kinetic energy. Heat/vibration is just a side effect of kinetic energy on a nano scale.

* Riven runs..!

[Drenius]

Maybe offtopic, but would you agree that any kind of energy is also a kind of movement, so energy is movement?

[matheus23]

bouncing against eachother

Wrooooooooong!
They don't actually get in contact with each other

* Philipp runs!

Maybe offtopic, but would you agree that any kind of energy is also a kind of movement, so energy is movement?

I don't think so. Is chemical energy movement? It's just tension between two particles, keeping them from getting apart from each other. I don't see any movment with a simple uranium atom. It's chemical energy is used in nuclear reactors.

[Opiop]

I took physics last year (10th grade), and possibly one of the coolest things I learned all year was that nothing actually ever touches anything else. As in, particles don't touch ever. Absolutely crazy to think that I have physically never touched anything, I just feel the heat coming off the atoms of other "objects" (or something, can't remember how the feeling of touch works).

[BurntPizza]

Maybe offtopic, but would you agree that any kind of energy is also a kind of movement, so energy is movement?

I would say that energy applied to mass results in movement of the mass, but I would not say energy is movement. Movement (or motion) is contextual to a physical body, usually a mass. (then there's photons and such)

It is sometimes difficult to differentiate these, as mass and energy are closely related. See http://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence

[BurntPizza]

I took physics last year (10th grade), and possibly one of the coolest things I learned all year was that nothing actually ever touches anything else. As in, particles don't touch ever. Absolutely crazy to think that I have physically never touched anything, I just feel the heat coming off the atoms of other "objects" (or something, can't remember how the feeling of touch works).

You feel the force exerted on your electrons by the electric field(s) of other electrons in objects you are "touching."

[Opiop]

I took physics last year (10th grade), and possibly one of the coolest things I learned all year was that nothing actually ever touches anything else. As in, particles don't touch ever. Absolutely crazy to think that I have physically never touched anything, I just feel the heat coming off the atoms of other "objects" (or something, can't remember how the feeling of touch works).

You feel the force exerted on your electrons by the electric field(s) of other electrons in objects you are "touching."

Ah, thank you. I had forgotten that. Physics really is interesting, I had a great time in that class.

[Riven]

bouncing against eachother

Wrooooooooong!
They don't actually get in contact with each other

* Philipp runs!

It depends on your abstraction level. You can see 2 'colliding' hydrogen atoms as solid spheres and the maths add up (almost like Newtonian physics), you can also go a few orders of magnitude 'closer' & 'shorter', and see how these atoms (or electrons/protons/quarks, if you will) exchange short lived particles, eventually resulting in them having a brand spanking new velocity vector.

[matheus23]

It depends on your abstraction level. You can see 2 'colliding' hydrogen atoms as solid spheres and the maths add up (almost like Newtonian physics), you can also go a few orders of magnitude 'closer' & 'shorter', and see how these atoms (or eletrons/protons/quarks, if you will) exchange short lived particles.

Shoot.
You win.

* Philipp sighs