Are We Living In a Computer Simulation? | Hacker News Reader

Are We Living In a Computer Simulation?

simulation-argument.com

34 pointsedu53 comments

The Simulation Argument is not that we are living in a computer simulation. It is that you must reject at least one of the 3 propositions:

(1) we are not living in a computer simulation

(2) the human species will give rise to descendants that have the power to run lots of simulations

(3) at least a few of them will run ancestor simulations.

Which of these three do you think is untrue? Alternatively you could reject the Simulation Argument that says the three propositions are mutually incompatible - but if so, how?

Personally I really doubt (2). I work in theoretical condensed matter physics, and it's awfully hard to accurately simulate anything with more than a very small number of atoms. Sure, computers will continue to get faster for a while, but these problems scale very badly with the size of the system, and we're not all many orders of magnitude away from the fundamental limits of computation. I suspect that even if you were to convert the whole mass of the solar system into one big computer, you probably still couldn't run a decent simulation of any system on the scale of 10^23 atoms.

It's possible you might be able to run a somewhat dodgy simulation which doesn't work on the atomic scale unless it has to (e.g. when your simulated person decides to do some atomic-scale experiments, it would suddenly launch a proper simulation, and otherwise it could get away with a neuron-level simulation). But I still don't think that we'll ever get the computing power needed to make these kinds of simulations trivially easy.

It may be possible that each universe will simulate a substantially simpler universe; it would of course be impossible to tell whether you universe has "lower resolution" from the inside, cause you'd have no frame of reference.

Perhaps our universe's resolution bottoms out at the quantum level, where a hack saves processing at the lowest level by using probabilities and a lazy evaluation scheme instead of deterministic calculations.

One possible solution is to elongate the time-steps; if we take a million years to simulate one second of simulation time you could get by with a lot less computing power.

If you do that, and load some information from a slow storage device (hard disk), calculate on it for a hundred years, then write it back, load some more, repeat, until you have computed "one planck time" accross your entire simulated universe...

... at what point in the loading, crunching, saving, does the information inside feel concious and self aware 'in realtime'?

Since this could apply to your life being run on a different substrate, with no actual effect on your perception, I don't see how this is a useful question.

The problem is that the scales involved are so ridiculously large that it could easily take 1 billion years to simulate one second. Even with 1 million years per second, simulation of a thousand years would require something like the age of the universe to compute. In that case, these "beings" could not be our descendants since they live in a universe with different laws.

Actually, at a million years per second, the age of the universe (so far) would go by in five simulated hours. I don't want to speculate on how long we have until heat death, but I doubt it's long enough to simulate a single human lifespan at a million years per second.

well perhaps a few options:

* Assume humans are the target of the simulation - our senses are fairly constrained (eg our focal point is only a tiny area where hi resolution is required etc...)

* What about non classical computing (quantum computing) - it may end up being nothing, but it seems to have some interesting promise in going beyond the raw computation power of atoms at least.

You're assuming that we'll be using the same approaches (e.g. molecular dynamics on classical computers) to do the simulation. We don't know what methods and techniques will be available in the future, so we can't confidently claim that it'll forever be out of reach. I bet there's some room for improvement over the current crude techniques.

But there are still fundamental limits, like the speed of light or the Bekenstein bound that forbid arbitrarily powerful computations.

I'm not saying that we'll have arbitrarily powerful computations, but that there's a lot more room for improvement. Like Feynman said, "there's plenty of room at the bottom".

Oh, I'm not assuming that. I'm just not-assuming the opposite.

When do you think Moore's law will fail?

Informational entropy causes a snag.

It is impossible for any information system to express all the information about a more complicated system than itself. Ie, the computer capable of simulating the entire universe, down to the smallest of the small would have to be bigger than the universe. (Because, whatever the smallest piece is that it tracks, it'll have to express that in something bigger, that smallest thing being the smallest thing that exists.)

The other alternative, is for the simulation to drop a lot of detail about the thing being simulated. But then we'd see compression errors. (Or, maybe that explains why QM sometimes seems like God just said, "F--- it, whatever, just flip a coin or something, I don't care"? ;)

What makes you think the entire universe exists?

You know, if you keep up this kind of intellectual exercise, you'll go blind.

Not necessarily, but already we're hitting up against the limits of what we we are capable of thinking.

I like the model of a computer universe. It makes sense to my consciousness. That's more than most of the other models, and it has some interesting consequences.

It was a joke. I was suggesting that this is mental masturbation.

When the theory can make a risky prediction that can be verified by an appeal to observable evidence, I'll consider it. Anything that starts with you'll never be able to test it, but... is not science or philosophy, but religion.

> Alternatively you could reject the Simulation Argument that says the three propositions are mutually incompatible - but if so, how?

Suppose the universe started normally a few billion years ago (explosion) and humans appeared several million years ago and we're not in any simulation right now. But at some point in the future there will be such simulations and "people" will "live" in them. Unlikely? Sure. Impossible? Nope.

After having just spend a bunch of time reading the "Why are geeks atheists" thread, this article cast an entirely new image of the phrase "Jesus saves" into my mind...

It's just another mind trick, enveloping the whole universe in something that we now understand (discret computer simulations).

Anyway, reality is an opinion, so any model is a valid model.

"reality is an opinion"

I like it. Can you explain further?

Off course immad, is based in the believe that using our brains as measurement tools for experiencing the universe we can only make models of it, partial maps (filtering a lot of information in the meanwhile). In this process we use our senses, experience, conditioning, prior beliefs, and other non-objective factors to create our unique map.

Every brain make his own reality tunnel (or reference frame) to experience the universe, and we may share some of it with other brains around (also called culture).

So if reality depends of the observer there must be more than one.

Before you start on this, what about the problem of consciousness? If the simulations can't give rise to consciousness, then I know this isn't the case.

What argument would have been made 100 years ago? Are we living in a steam engine?

That we are living in a book. Note that the popular plot device of being trapped in one (or more) books survived intact as being trapped in the TV and being trapped in a virtual reality game.

If you watch kid's cartoon series, you know that this plot device is as inevitable as the Freaky Friday contrivance.

Yeah, that's precisely the point I was trying to make (I think). It's the same basic mental model, "we ARE the technology we use." As it evolves, so does the theory.

Like McLuhan said, "We shape our tools, and then our tools shape us."

Exactly. Different observer, different models.

Throughout my youth, I always considered a similar thought experiment.

Make the assumption you were some higher power with no concept of 'time' (or lived forever in our concept of time). What would you do? Well, I believe you would get very bored quickly, and the only logical solution is to run some experiments. I would start small (lets for arguments sake say at the molecular level, but almost certainly it would be at a smaller level in our perceived world) and create every possibility. That would not take very long - so you would have to create an infinite number of expanding test areas. Each one of these you could equate to what we consider our universe. So basically you are testing every possible 'path' that could exist.

I haven't put it very well to words here due to time constraints - but basically it seems like a logical conclusion that we exist in one of these 'paths'.

"Make the assumption ... it seems like a logical conclusion"

For me, that sums up the problem with this kind of thing. Assumptions don't lead to logical conclusions, but "meta-assumptions" which have grown out of your original one. You can't put assumptions in one end of your experiment and get facts out the other, unless you can test your ideas.

Incidentally, I'm not hostile to your idea or the others discussed here. It's fascinating, but (like anything for which we can't acquire proof) my own belief is that it's not very useful.

Not this again...

It depends if the universe is capable of computation.

I think the fallacy here is the definition of "ancestor simulations". What does that really mean? I think it's more likely that posthumans will run simulations of whatever interests them at the time, which will probably not be the past. What they will want to know is what lies ahead.

Therefore, my scifi mythology is that we are in a simulation created by some other culture (ie not human).

Whoa. Déjà vu.

http://en.wikipedia.org/wiki/Simulated_reality#We_are_living...

http://cosmicvariance.com/2008/01/10/is-the-universe-a-compu...

I find the theory full of holes... 1) Just think about the amount of power needed by a system to maintain such a virtual world 2) Consider the magnitude of the power needed to further maintain a nested system/S within itself???

[....besides.. i doubt amazon ec2 could scale this kind of thing anyway \)

That doesn't bother me. Presuppose a fancy, futuristic computer that can handle it, and -- bam -- problem solved.

What bothers me is that it's tautological. It's meaningless and banal.

Well, nowadays philosophy is often meaningless. But I think it's a good exercise only to train our mind to think about non-conventional theories. Probably it's a lite version of 'What you can't say' http://www.paulgraham.com/say.html.

Evidently, it's a question whose answer is unreachable and, in my opinion, completely irrelevant (i really don't care if there is/isn't god, if we are a computer simulation, or if I'm a potato).

It's no worse than religion, and more likely to be true, from my perspective.

I have trouble understanding how the meaning of our existence or lack thereof is banal.

From the FAQ:

Do you really believe that we are in a computer simulation?

No. I believe that the simulation argument is sound.

That he thinks the argument is sound but does not agree with "(3) we are almost certainly living in a computer simulation" means Bostrom believes either:

(1) the human species is very likely to go extinct before reaching a "posthuman" stage; or

(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof).

No, he may be entirely agnostic on all three, neither believing nor disbelieving any of them.

That seems like a pretty sensible attitude to have, actually.

In the FAQ, Bostrom says he personally assigns about 20% probability to the idea we are living in a simulation, and that he views (2), that the posthumans are unlikely to run ancestor simulations, a bit more likely than the others.

Colloquially, it would be fair to say he 'believes' (2) -- as in the most likely of exclusive options, if he had to make one choice, if he had to bet, etc. And he definitely believes Union(2+3) more than (1).

man you all really hate this idea. why? I hope its not just because its a thought experiment you guys are afraid to think about.

I personally love this thought experiment and the consequences one can reach from it.

It's not that this is shockingly new, it's that it's exceptionally unoriginal.

Every 15 year old has done all these thought experiments already. Brain in vat. What happens to personalities when you clone? What happens if you copy a brain on the molecular level - do you get two different people or not? Are you the same person you were 20 years ago? Even though every cell your body has been replaced?

It's just psych 101. Not topics you can discuss over and over again.

The computer simulation model is uninteresting because you can't use the model to make predictions that can be tested. And if you can't make useful (or interesting) predictions the model stinks.

What psych 101 class did you take?

Philosophy. Not psychology. My bad.

What is interesting though is that no matter how unoriginal the question are we still don't have accepted answers, which suggests that it isn't time to stop asking the questions (which is unfortunate for those who are sick of the questions).

No.

do not try and bend the spoon. That's impossible. Instead... only try to realize the truth. There is no spoon.

Yes.

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