Physicists To Test If Universe Is A Computer Simulation • Hacker News Board

Re: Physicists To Test If Universe Is A Computer Simulation

#191

Post by aswanson » Thu, Apr 18, 2013, 2:53 AM UTC

nilkn wrote: post #186

aswanson wrote: post #148

Earlier quoted context omitted.

The objection is totally relevant because you cannot calculate probabilities if you don't know the number of real universes, the probability of life arising from non-life, etc. I would argue, using that line of reasoning that it is more likely that we would be a dream of a sentient entity rather than a simulation of one if his probabilistic assumptions are taken as probable.

Dreams only last a few hours, so that's not really a possibility. If you are proposing we are the "dreams" of a sentient and extremely advanced machine, then that is hardly different from saying that we are just simulated. And I'm pretty sure the numbers you mentioned--like the number of real universes, the probability of life arising from non-life--really don't come into it at all. Skimming over the paper, none of t…

Im not talking about universes within universes. Let's take our own universe as an example, and using probability as we know it in our own as holding in whatever 'real' universe(s) that may or may not simulate itself or some subset of itself. If sentient beings evolve (taking Bostroms postulate of that probability as reasonably high) and assuming they 'dream' if they are anything like us, as he does, and since we have (yet) to develop a technology that can simulate a universe as complex as ours, it's far more probable that sentients evolve and dream universes than evolve and simulate us. Even in our own "existence" (whatever that means) you have to agree that there have been far more dreams than games played. This follows probabilistically; not all people play games but almost every human that has ever lived has dreamed. Therefore it is far more probable that we are a dream, or passing thought, for that matter, than an intended simulation. Hinduism win.

Re: Physicists To Test If Universe Is A Computer Simulation

#192

Post by aswanson » Thu, Apr 18, 2013, 2:56 AM UTC

gwern wrote: post #95

aswanson wrote: post #55

Earlier quoted context omitted.

Bostrom's postulates are exceedingly bad. His assumptions rely to much on the isotropy of properties of the one "real" existence and the simulated ones. I would expect, statistically, that there would be far more universes simulated that have properties that are nothing like the "real" one as technology progresses, i.e. there are more instances of "sonic the hedgehogs" and "super mario brothers 1" over the more "real…

> It follows that if our universe is one of the more probable universes that our laws of logic and probability estimates are not calculated from probable postulates, thus our assumptions leading to any conclusion are probably in error. What 'postulates' would they be calculated from? Does it even make sense to speak of universes following different 'logics'? > far more universes simulated that have properties that ar…

What 'postulates' would they be calculated from? Does it even make sense to speak of universes following different 'logics'?

Exactly the point. What game do you know of that follows the laws of logic as we know them in the 'real' universe we habitate? It follows that it's nonsensical that we can reason ourself to reality if we are a simulation.

Re: Physicists To Test If Universe Is A Computer Simulation

#193

Post by aswanson » Thu, Apr 18, 2013, 3:02 AM UTC

XorNot wrote: post #98

endtime wrote: post #35

I think it's a bit silly to try to infer things about the computer that could be simulating our universe based on things internal to the simulation. Many of our fictions don't have the same laws of physics as we do.

It's a hypothesis - namely, that the entities running the simulation are trying to simulate their own universe to make deductions and discoveries about it. Therefore, our universe would be a reasonable facsimile of there's in most respects. Which has the implication that their may be limitations on their computational substrates which required workarounds or optimizations, or as the lattice QCD case points out - whic…

'Sense' is from the perspective of your limited (human) viewpoint. It makes no 'sense' to me that a civilization advanced enough to simulate a whole universe for the purpose of study would be stupid enough to expose such a bug/limitation that would expose their (possible) existence before we even built the first transistor.

Re: Physicists To Test If Universe Is A Computer Simulation

#194

Post by jonnathanson » Thu, Apr 18, 2013, 3:07 AM UTC

polshaw wrote: post #175

jonnathanson wrote: post #167

Earlier quoted context omitted.

"What I would like to discuss is what purpose would simulating a universe have for the advanced civilisation?" The Douglas Adams-style answer would be that we're some kid's physics homework. Perhaps, in a sufficiently advanced civilization, building a working computer model of an advanced universe is child's play. An alternative is that the simulators inhabit a very different universe from our own, and that our simul…

If we are to say it is a perfect or near perfect simulation ('copy') then I don't see how, as stated in my first post. It's interesting to consider if we were a different simulation. But it would still have the same limits (that the sum of the activity ('reality') in each simulation must be less large/complex than it's host), prohibiting the 'infinite simulations' concept. It surely isn't necessary that we are simila…

"It surely isn't necessary that we are similar to a host universe, but I wouldn't you say it was a necessary part of this theory?"

I don't think it's a necessary part of the theory, but it's a necessary part of the test we would need to conduct. And given that such a test is simply testing for inconsistencies, artifacts and bugs inherent to our own universe/simulation, it's possible to detect whether we're in a simulation without having to test for the precise nature of it (or the nature of the simulators).

But our tests are inherently being conducted from our own frame of reference, with our own understanding of what should and shouldn't be found. Ergo, we can prove a simulation by finding artifacts of one as recognizable to us, but we can't necessarily disprove a simulation by not finding artifacts.

That being said, the proper way to think about the test wouldn't be "Physicists are testing to determine if we're in a simulation." It would be "Physicists are testing to find evidence that we're in a simulation."

Re: Physicists To Test If Universe Is A Computer Simulation

#195

Post by qu4z-2 » Thu, Apr 18, 2013, 6:16 AM UTC

devb wrote: post #41

It's apparently a good time to link to a writing entitled "Creating Infinite Suffering": http://www.utilitarian-essays.com/lab-universes.html "Abstract. I think there's a small but non-negligible probability that humans or their descendants will create infinitely many new universes in a laboratory. Under weak assumptions, this would entail the creation of infinitely many sentient organisms. Many of those organisms wo…

Makes me wonder: Is computing universes with a computer all that different from simulating universes with imagination?

Re: Physicists To Test If Universe Is A Computer Simulation

#196

Post by qu4z-2 » Thu, Apr 18, 2013, 6:28 AM UTC

cscheid wrote: post #10

seanmcdirmid wrote: post #3

Earlier quoted context omitted.

Imagine if you not only realized you were living in a simulation but that the simulation involved randomness (god playing dice) and you could somehow force backtracking with a simple button so that different values were chosen. Now, play the lottery and hit that button whenever you don't win; you could then surface an unlikely universe where you get really lucky.

Have you heard of Max Tegmark's quantum suicide argument? If you believe it sufficiently, well, buy a lottery ticket and cyanide, and really commit yourself to it :) (No, please, do NOT do this.)

Hah, that's very cool. I came up with this as an idea for a short story a couple of days ago (except slightly more drastically, as it involved the complete annihilation of humanity on a failure condition, allowing the practitioner to drag everyone else with him into his preferred outcome-world). I'm simultaneously pleased and displeased that someone's already given it a lot of thought.

Re: Physicists To Test If Universe Is A Computer Simulation

#197

Post by Houshalter » Thu, Apr 18, 2013, 12:37 PM UTC

tcgv wrote: post #160

Houshalter wrote: post #124

Earlier quoted context omitted.

There is a similar argument against AI. That a computer can't "feel" or experience any of the sensations we do. If you type 'emotional_state = "happy"', does that mean your computer feels happiness? Even if you have a complex simulation of neurons, if you zoom in, all you will see is little electrons bouncing through various logic gates and ending up in some kind of pattern. But the thing is, the exact same thing is…

"But the thing is, the exact same thing is true for your brain too!" That is pure speculation. Just because we can observe similarities between two phenomenons it doesn't mean they are the same thing. You're erroneously assuming that the universe can only work in a way that fits our theories and models.

What are you suggesting? That the brain fundamentally is not a machine, a process of some kind? Even if everything we know about the universe was wrong, which could be true, but it is far, far, far from pure speculation. You might as well say it's pure speculation that gravity exists.

Re: Physicists To Test If Universe Is A Computer Simulation

#198

Post by Houshalter » Thu, Apr 18, 2013, 1:20 PM UTC

pdonis wrote: post #166

Houshalter wrote: post #124

Earlier quoted context omitted.

There is a similar argument against AI. That a computer can't "feel" or experience any of the sensations we do. If you type 'emotional_state = "happy"', does that mean your computer feels happiness? Even if you have a complex simulation of neurons, if you zoom in, all you will see is little electrons bouncing through various logic gates and ending up in some kind of pattern. But the thing is, the exact same thing is…

Complexity isn't what makes something intelligent or conscious after all. Why not?

This is a good explanation http://lesswrong.com/lw/ix/say_not_complexity/

Re: Physicists To Test If Universe Is A Computer Simulation

#199

Post by Houshalter » Thu, Apr 18, 2013, 1:53 PM UTC

randallsquared wrote: post #150

Houshalter wrote: post #124

Earlier quoted context omitted.

There is a similar argument against AI. That a computer can't "feel" or experience any of the sensations we do. If you type 'emotional_state = "happy"', does that mean your computer feels happiness? Even if you have a complex simulation of neurons, if you zoom in, all you will see is little electrons bouncing through various logic gates and ending up in some kind of pattern. But the thing is, the exact same thing is…

> The only thing I can think of is that the character in the book is far simpler than a human. Words that say "john is happy" is similar to setting a variable on your computer equal to "happy". Happiness in a human is far more complex, involving tons of interactions between neurons. But this answer isn't satisfactory to me. Complexity isn't what makes something intelligent or conscious after all. This is the differen…

Well I'm not really claiming the book is sentient, just trying to come up with a criteria that excludes books and everything else except for people, without being completely arbitrary.

Anyways you can think of time as a dimension. Each moment of time exists, connected to the ones that came before and come after it. You can represent the every state that a turing machine goes through all at once. Just like those rows of rocks. What does "running" even mean in a universe where all points in time can exist at once?

But regardless of that, you can still say the book is "running" when it is being written or when it is being read. The characters don't just exist in the book, but literally in your mind. Though I still wouldn't call them conscious or even intelligent.

Re: Physicists To Test If Universe Is A Computer Simulation

#200

Post by randallsquared » Thu, Apr 18, 2013, 4:50 PM UTC

Houshalter wrote: post #199

randallsquared wrote: post #150

Earlier quoted context omitted.

> The only thing I can think of is that the character in the book is far simpler than a human. Words that say "john is happy" is similar to setting a variable on your computer equal to "happy". Happiness in a human is far more complex, involving tons of interactions between neurons. But this answer isn't satisfactory to me. Complexity isn't what makes something intelligent or conscious after all. This is the differen…

Well I'm not really claiming the book is sentient, just trying to come up with a criteria that excludes books and everything else except for people, without being completely arbitrary. Anyways you can think of time as a dimension. Each moment of time exists, connected to the ones that came before and come after it. You can represent the every state that a turing machine goes through all at once. Just like those rows…

> What does "running" even mean in a universe where all points in time can exist at once?

If they all exist at once, then in what sense are they connected? Certainly not a causal sense, which I would argue matters quite a lot.

> The characters don't just exist in the book, but literally in your mind. Though I still wouldn't call them conscious or even intelligent.

If your mind was able to simulate the actual process of consciousness in the brain of the character being read about, then I would argue that the character could be conscious. Of course, brains don't have that much additional processing power. :)