Rebuilding Quantum Theory From Simple Physical Principles
quantamagazine.org
quantamagazine.org
Neutrinos aren't massless
Confirmed higgs
> Problems
Hierarchy problem
Fine tuning
Why is the cosmological constant so "wrong compared to theory"
No evidence for supersymmetry yet at 10^-17cm via LHC
No evidence for WIMPs
How do we combine QM + GR?
Do black holes destroy information? How to solve the BH firewall problem?
> Speculation
Is there supersymmetry at higher energies than the LHC can probe?
Is spacetime doomed? I.e. is space-time a hologram on the boundary or some other emergent phenomenon
Is there a multiverse?
Is decoherence a solution, or does the wave function "collapse", or simply many-worlds?
Is perturbation theory sensible or is there a deeper more elegant way to calculate scattering?
Is time emergent or fundamental?
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.
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.
This one is very interesting since it brings back the question what time really is. Your point involves “metacircular” observer that can only work/simulate as fast as it can, but the definition of “fast” is external to it. Sure, if we simulate predefined-but-calc-required in our universe, then it will take time. But why should we measure it this way? I mean, does calculation process exist at all without something that requires time for it?
[Or we’re really talking about the same fundamental thing that lies behind both our and hypothetically deterministic universe.]
Then, according to this idea, the calculation can not be simplified by using some kind of formula that predicts the final state, and one needs to fully compute all the intermediate states, which means your computation is fully equivalent to that person living for the time for which you want to calculate the final state.
So time here is the internal time for the system of your calculation, and not related to the time you take to calculate. This internal time is nothing more than a counter you use, and You can actually stop your calculation, change something in the initial state and calculate again.
I find this fascinating because it kind of explains the universe being predictable, and people having free will: everything is predefined, but only way to know what the choice of complex system will be is letting that system to make the choice!
If the view that consciousness can be explained without requiring quantum physics is correct, then this is true independently of specifics of simulated/real universe, and is just the way information/computation works.
But then maybe Penrose is right, and consciousness can't be calculated on a Turing machine, and we still have lots of interesting science to discover.
It is common to base such thoughts on analogies between our universe and our computers, i.e. our computers have only finite precision while the universe seems continuous, at least to a very good approximation. Therefore if we would detect rounding errors in the universe we would know that the universe is actually a simulation.
But that is at least naive and most likely not true. How would you know that a real universe does not have finite precision? Why would you assume simulation must have finite precision? And you have to answer the same question for any other feature you want to use to make the distinction.
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.
But the question "is simulation possible, and if yes what it can look like" is new, and can have useful answers.
That is pretty interesting, but now how most people formulate the issue. After all, what we could simulate, or what could be simulated in a universe like ours, in principle is pretty interesting. The question of what another reality simulating us would be like isn't, because it could be absolutely anything at all. Questions without the hope of answers are, to me at least, not interesting.
So if by not interesting you mean `this door is closed now, revisit later` i completely agree with you!
The reason is that we can safely assume that we are within one of n + 1 realities. The n simulated realities and the 1 real reality. Unless you attribute some sort of exceptionalism bordering on creationism to our existence, there's every reason to think that n is going to proportional to the number of advanced civilizations in existence and is presumably going to be very very large. And as you increase n the odds of us actually being in the 'real' reality, which are of course just 1/(n+1), approach 0.
Like you mention it's something that doesn't necessarily go anywhere. Even if you "prove" it after death, that life you'd be experiencing at that point faces the same logical issue - at least unless the argument loses consistency at some point. Something most seem reluctant to admit is that it's also comforting as an atheist. I always expected the infinity of time after my existence to be very much akin to the infinity of time before my existence. That's just disappointing. The seemingly high probability that all is not as it seems is certainly emotionally appealing. But it's certainly not just the emotional appeal driving me there - I could obviously have chosen to invoke Pascal's Wager in the decades of time prior to considering this, but it seemed fake -- this, somehow, does not.
It also answers, or at least compellingly kicks the can, of the question of existence. If I write a program to spit out a random number, I presume that there is no entity that suddenly whisks into existence under the false impression that it is choosing a random number - which it then decides upon, before then being whisked out of existence. So why am I, the 'thing' spectating the outcome of the series of chemical and electrical reactions carried out by this body, here? Descartes would have quite the time if the answer to our little question had been yes during his time. It changes the picture so much more than the dreams that drove his ponderances.
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From a scientific point of view, it's obviously not a great concept as it cannot be falsified. And like you mention, it also cannot really be physically proven without begging the question. On the other hand, it can be treated as a soft science and if a preponderance of evidence does lean towards supporting it then we can at least say, "Hmm.. well we can't really say anything for certain, but that's certainly interesting."
That's a key proposition and you don't support it at all. I find the idea highly questionable.
Or what if, while you are asleep, someone essentially detaches your brain from your body and uses the signals your brain sends to control a simulation of your body in a virtual environment and feeds back the simulation output into your brain as what you see, hear, feel, and smell? How would you detect that you are no longer really in the real world when you wake up?
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 that it's in a bubble managed by some outside system.
Is your argument entirely from lack of imagination in how it could be done?
Only because minecraft does a lot of things to save from doing extra work, like unloading chunks or skipping frames if it's under load. If you remove those optimizations (and add some error-correcting ram or a redundant process to double-check calculations to protect from cosmic-ray-induced errors), then it's easy to make a minecraft-like game that's deterministic across platforms and doesn't reveal details about whatever platform it's on.
Take something like Ethereum's blockchain: it's not possible for an executable turing-complete contract to know what type of computer it's executing on, because the VM is strictly specified, and if there were any flaws that accidentally revealed information from the environment, then every nearly every node in the Ethereum p2p swarm would get different results and the blockchain would fork ridiculously and practically halt as all nodes desynchronized from each other until people updated the software to fix that bug.
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.
The point is that reality is little more than what you experience. All that simulating a reality requires is that an individual's experiences are able to be constrained to within the controlled ream. Take a child, 'disable' all senses except sight - and install permanent VR goggles. That child, lacking outside interference, will believe in a reality that is not really real. Should it develop the cognition to wonder it will likely do as we do. Why do large bodies attract one another? We can explain the operation of this through perhaps the curvature of spacetime, but that then again one can ask then why is there spacetime? At some level the answer simply ends up being that because that is the way it is - a inherent facet of our universe.
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 reality) to them.
You can only make it take more time by suppressing noise, but eventually the "errors" will carry accurate information inside. (And someone inside can accelerate this process by causing noise in certain manners.)
> lacking outside interference
Depending on your interpretation of quantum mechanics, this is either impossible (Bohmian; maybe all of them) or insufficient (Copenhagen, MWI) -- in either case, small "errors" will reveal information about the actual nature of reality.
The Cave itself is only given definition in terms of what we might call the Ultimate (in a Platonic setting); though it's essence is to obscure the Sun (a symbol of the too bright to observe Ultimate), the very ability to do so is fundamentally related to the fact it's also a manifestation of the Ultimate.
Similarly, the Fire and anything used to cast Shadows. By careful observation of the nature of Shadows and Light from the Fire upon the Cave, we observe a manifestation of the Ultimate interacting with itself, because the Light from the Fire is merely a transposition of Truth from the Sun, while the essence of the Cave is revealed in it, and we can see the Ultimate through the lens of the Cave.
It's fundamentally impossible to separate the manifestation of an Essence from an expression of the Ultimate interacting with itself; ergo, any structure capable of self interacting and capturing its "Errors" will find in them the ability to distill a view of the Ultimate.
-- the argument is pretty endemic to any structure capable of expressing existing: what exists cannot be cut off from the nature of existence, because fundamentally it's doing that.
(Also, first time I think those philosophy classes came in handy.)
Then again it might have already happened, and we got rolled back to the last known good image.
The argument that we are most likely in a simulation because there are many of them and only one reality doesn't sit well with me either. Nobody at any level of nested simulations would be justified to believe that he is not simulated but actually lives in the outermost real universe. So why is it more likely that someone else lives in the real universe than us? Someone has to be the exception, why not us? I am unable to formalize it and maybe I am just committing a logical error, but something seems wrong to me if the conclusions everyone draws are, when taken together, obviously wrong, i.e. everyone concludes he is almost surely not in the outermost level but someone certainly is.
There's a logical slip in your math. It is not more likely that someone else lives in the real universe than you. It's equally improbable. And the more simulated the realities, the less probable of any given civilization existing within the real one. Just picture it as balls in a bag. There are 'n' black balls representing the number of simulated realities one may be within, but just 1 white ball representing the real reality. And like you mention, even if somebody was able to reveal and 'disable' the simulation of their reality -- the same logic holds (that the new unveiled reality is likely also false), unless there is some newfound reason to think it might not.
Universe simulations would be very resource intensive and advanced civilizations would have better uses for those resources. You may very well get some highly advanced simulations from the advanced civilizations, but they would likely me on a much, much, much smaller scale than the containing universe.
E.g., if there are a billion simulated universes, they may each be a trillionth the scope of the real universe. So your odds of being in the real universe are 1/(0.001 + 1), or almost 1.
Simulations can't be 100% efficient -- If a system was, I don't think it would be considered a simulation, but just a place in the regular universe -- but even if it were, simulating a solar system would take the full resources of an entire solar system. It's hard to see why an advanced civilization would devote those kinds of resources to creating simulations or if one did, how it would survive for long to maintain it.
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 software.
3) This is objective of course, but quite a lot of people are experiencing coincidences that seem unreal. That sounds metaphysics and most of us wouldn't touch it with a barge pole but from a simulation perspective makes total sense.
Oh and it makes a lot of people uncomfortable. For me it's one of the best ways to test someone's intellect. You bring it into a conversation and people start feeling unease.
This is not even remotely true, not even if a perfect Moore's law were to continue for thousands of years. Man, we're hard pressed to even simulate single molecules.
> quite a lot of people are experiencing coincidences that seem unreal
Oh come on x) "Coincidences" are psychological illusions and misatribution biases at work, not the work of an intelligence behind our universe. This is the "I prayed to god and my back pain healed; it's a miracle" type of thinking.
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't see any obvious evidence for that. And even then I think it could not work because if the universe is in some sense redundant and could be compressed then it actually provides less resources to work with than if it would not have those redundancies.
Take as an analogy for the later two processors executing the same code in lockstep as it is sometimes done for redundancy in safety critical systems. You can mostly get away with only simulating one of the processors but you essentially also only have one processor to work with. And while you can probably simulate the processors on the processors the simulation will probably be at least ten times slower than the actual processor if you only want to use one tenth of the available resources, i.e. clock cycles. And finally memory will be a real problem because you only have as much memory available as you want to simulate.
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 be digital or analog. If the size of such device can be comparable to the size of human body, then we can create a useful simulation.
And I don't think it would be meaningful to say the universe is the simulation. A processor executing some code is not a simulation of a processor executing some code, an electron flying across the room is not a simulation of an electron flying across the room, a dog walking down the sidewalk is not a simulation of a dog walking down the sidewalk. A simulation requires, at least that would be my ad hoc definition, one system recreating the states and behaviors of a different system, they can not be the same system.
Now, in the end, if we are in a simulation, that simulation (or one of its "parents") is reality, and so effectively we are all bound by the physics of the base reality, so one could argue that there is no harsh line between our simulations' physics and reality's physics, but that's another thread ;)
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?
They all share roughly the same idea, there is some reality but by some perfect arrangement of smoke and mirrors you are by definition unable to ever learn something about that reality. There is certainly some value in discussing those ideas on a meta level, finding common characteristics, figuring out limits, but beyond this the individual ideas are, at least in my opinion, mostly a waste of time. What is the point of analyzing something that by definition leaves you stuck?
And as far as I can tell philosophy has long ago mostly accepted this and made it something like an axiom that there is an reality and we can learn about it and doesn't concern itself much anymore with ideas that would, if true, block any possible progress.
https://www.quantamagazine.org/pilot-wave-theory-gains-exper...
> An experiment claims to have invalidated a decades-old criticism against pilot-wave theory, an alternative formulation of quantum mechanics that avoids the most baffling features of the subatomic universe.