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Rebuilding Quantum Theory From Simple Physical Principles

quantamagazine.org

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Re: Rebuilding Quantum Theory From Simple Physical Principles

#31

Post by elorant »

danbruc wrote: post #18
elorant wrote: post #16

Earlier quoted context omitted.

It is appealing for three reasons. 1) As computer engineers we understand it's doable. Give it a couple of centuries and our civilization could reach a computing capacity to simulate the entire observable universe 2) A lot of things just don't make sense. Like consciousness for example. We can't define it, and we don't even know it it's real. If you take consciousness out of the equation humans are just laborious sof…

As computer engineers we understand it's doable. Give it a couple of centuries and our civilization could reach a computing capacity to simulate the entire observable universe This seems at the very least questionable. Why do you think you can simulate the entire universe just using a tiny fraction of the resources of the universe? It seems to me that could only work if the universe were highly compressible and I don…

For all we know, 99,999% of the universe could be just a projection. You don't need to simulate all of it down to the proton level, just the things we can see. And the reason our cosmological theories fail miserably in things like dark matter or dark energy could be because there's really nothing out there.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#32

Post by SomeStupidPoint »

danbruc wrote: post #27
SomeStupidPoint wrote: post #21

Earlier quoted context omitted.

Yes, lots of ways: For example, in Minecraft you can build a redstone interferometer to detect things about the computer you're executing on and over time the statistical behavior will detect the physics of the real system. A character in Minecraft could build a cosmic ray detector, for instance. So yes, absolutely -- my expectation is that any intelligent structure in a computational "bubble" will be able to detect…

Is a redstone interferometer an actually thing, a quick search didn't turn anything up? But even if you could detect influences from the outer reality within the game world, how would you decide between them being part of the game mechanics and them being shadows of the outer world given that you have no ground truth knowledge of what the game is supposed to be like?

> Is a redstone interferometer an actually thing, a quick search didn't turn anything up?

I'm probably using slightly different terminology than other people -- I haven't played much in a while.

The basic idea is to use two quasi-connected redstone wires hooked up to a piston -- one providing an update signal but no power and one providing power but no update signal.

The circuit is such that the two wires are actually branches off of a single redstone wire, using only redstone -- so you can detect if the left or right branch off of a redstone line updates first (within a single update cycle) based on if the piston extends: it only extends if the line carrying the update signal is updated after the line carrying the power signal. (If they come in the other order, it stays retracted because it updates before there's power available.)

> how would you decide between them being part of the game mechanics and them being shadows of the outer world given that you have no ground truth knowledge of what the game is supposed to be like?

You only have an operational model, just like us -- but it's eventually going to look like an extremely localized computation running their world that occasionally gets bumped by outside sources. That sounds like them discovering that their reality is a subregion hosted in another, richer reality.

The question of "game mechanics" only has meaning to the people outside in their language for discussing their actions -- at the end of the day, there is no "game", there's only what the simulation does as a facet of reality. The people inside will accurately suss out a model that includes a structure that looks like them being run as a simulation.

How they interpret that is likely to be different, but no more or less correct, than how we do.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#33

Post by chr1 »

QAPereo wrote: post #8
danbruc wrote: post #6

Earlier quoted context omitted.

I have to disagree and I can not really understand what is so appealing about the simulation idea to many. It is an idea that will lead nowhere because you are unable to distinguish a real universe from a simulated one. In order to do this you would have to know what at least one of those scenarios looks like and then compare the universe you observe to what you know to be true about a real or simulated universe. It…

I have to disagree and I can not really understand what is so appealing about the simulation idea to many. You can’t see the appeal of an unfalsifiable conjecture that everything including us, is an intentional creation of some manner of vast and powerful intelligence? Aliens, Simulators, Bulk Beings, or you know... Gods. It’s just new window dressing on an ancient dream.

The question "whether we live in simulation" is indeed a new dressing.

But the question "is simulation possible, and if yes what it can look like" is new, and can have useful answers.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#34

Post by danbruc »

chr1 wrote: post #29
danbruc wrote: post #18

Earlier quoted context omitted.

As computer engineers we understand it's doable. Give it a couple of centuries and our civilization could reach a computing capacity to simulate the entire observable universe This seems at the very least questionable. Why do you think you can simulate the entire universe just using a tiny fraction of the resources of the universe? It seems to me that could only work if the universe were highly compressible and I don…

You don't need to simulate the entire universe, just the tiny bit where interesting things are happening (read surface of earth), places farther away can be simulated with much lower precision as long as they look plausible. In that sense the universe is indeed highly compressible as it is mostly empty/uninteresting. The question is how large computing device is needed to simulate a brain, and whether that device can…

The part of the universe that is empty also provides nothing you can use for a computer to run a simulation on, i.e. you don't have to simulate it but it doesn't help running the simulation either. And given that we probe the entire visible universe looking at gravitational waves from across the galaxy, spectral lines in the light of galaxies at the other end of the universe, and the decay products of Higgs particles, you still need a quite good simulation or good heuristic approximations for a lot of stuff in order to not produce inconsistencies. Or you have to limit what your simulated humans can do and keep them actively away from discovering your speed optimizations. Faking parts of something as complex as our universe without it becoming obvious would probably not be a small feat.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#35

Post by wruza »

After familiarizing with QM/SR concepts some years ago, I came to the conclusion that there is nothing more strange and pointless than the world without these two. If max speed was infinite (or finite but non-relative, which is essentially the same) and there was no probabilistic outcomes, then the world would "happen to the end" instantly and/or with analytically predefined series of events. From any initial state. The entire "consequence" concept would fall apart. There is no point for the universe to exist in classical & atomic-ball electron mode.

Idk why both seem so unnatural to so many people who try to get what it means; it feels like it should be obvious instead - it means evolving existence, the only thing you're able to appear in and think about it. Classical uniform fundamental time is much stranger to me than what emerges from what we have now; we simply shifted our focus to "oh" forgetting how much "wtf" was left behind.

I'm not claiming any deep-enough physics or math knowledge (layman actually), consider it a funny philosophical view.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#36

Post by danbruc »

chr1 wrote: post #30
danbruc wrote: post #28

Earlier quoted context omitted.

To look for imperfections in a simulation requires knowing what the real thing actually looks like. If our universe is a simulation, where do you get the knowledge from what a real universe looks like?

You can look for contradictions, inconsistencies or for macro scale phenomena not explainable by micro scale laws.

That doesn't work. The rules used by the simulator could just be the rules of the real universe, you can not tell the difference. Or to put in programming terms, you are given an object x to inspect, our universe, and you have to decide whether it is an instance of class RealUniverse or an instance of class SimulatedUniverse but you have no knowledge of what any of those classes looks or behaves like.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#37

Post by danbruc »

elorant wrote: post #31
danbruc wrote: post #18

Earlier quoted context omitted.

As computer engineers we understand it's doable. Give it a couple of centuries and our civilization could reach a computing capacity to simulate the entire observable universe This seems at the very least questionable. Why do you think you can simulate the entire universe just using a tiny fraction of the resources of the universe? It seems to me that could only work if the universe were highly compressible and I don…

For all we know, 99,999% of the universe could be just a projection. You don't need to simulate all of it down to the proton level, just the things we can see. And the reason our cosmological theories fail miserably in things like dark matter or dark energy could be because there's really nothing out there.

If 99.999 % of the universe is fake, than you only have to simulate 0.001 % of the universe but you also only have 0.001 % of a universe to turn into a computer and run a simulation on.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#38

Post by chr1 »

wruza wrote: post #35

After familiarizing with QM/SR concepts some years ago, I came to the conclusion that there is nothing more strange and pointless than the world without these two. If max speed was infinite (or finite but non-relative, which is essentially the same) and there was no probabilistic outcomes, then the world would "happen to the end" instantly and/or with analytically predefined series of events. From any initial state.…

> with analytically predefined series of events.

This doesn't make universe less interesting or more predictable. Consider Mandelbrots set, it is fully analytically predefined, but only way to find it's details is to perform the whole calculation.

Similarly the universe can be predefined, but the only way of finding its state after some amount of time can be performing a calculation fully equivalent to letting the universe to live for that time.

Re: Rebuilding Quantum Theory From Simple Physical Principles

#39

Post by openasocket »

SomeStupidPoint wrote: post #26
indubitable wrote: post #20

Earlier quoted context omitted.

Consider that your perception of reality is just that. What your brain tells you and what is really there are not necessarily the same thing. There was another excellent article on QuantaMagazine arguing that there's even an evolutionary imperative that would drive our brains to beneficially misrepresent reality: https://www.quantamagazine.org/the-evolutionary-argument-aga... That article is a bit of another very int…

A child you made deaf like that would still discover sound as the vibrations that distorted the lenses on the eye once detection got sensitive enough. I dispute the very notion that it's possible to cut someone off from the basic nature of reality, because you must fundamentally have constructed the cage from that reality and thus their interaction with their cage will reveal its mechanics (and hence the mechanics of…

If you didn't know, his example is just a re-hash of Plato's cave: https://en.wikipedia.org/wiki/Allegory_of_the_Cave

Re: Rebuilding Quantum Theory From Simple Physical Principles

#40

Post by WhitneyLand »

danbruc wrote: post #6
dboreham wrote: post #2

Reading this I see for the first time why the notion that the universe is a simulation isn't so far fetched.

I have to disagree and I can not really understand what is so appealing about the simulation idea to many. It is an idea that will lead nowhere because you are unable to distinguish a real universe from a simulated one. In order to do this you would have to know what at least one of those scenarios looks like and then compare the universe you observe to what you know to be true about a real or simulated universe. It…

You have basically said it may be unprovable.

First, that may be true, but it also may not be true.

Secondly even if it were true, why would that change anyone’s interest or curiosity about it being a possibility?

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