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Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:14PM (#41782770)
Thought experiment on the nature of reality:

- In a much larger universe, write down in a log book every event to every particle at every instant, from the Big Bang to the restaurant.

- Put it on the fireplace mantle and leave it there.

This is basically a log of a simulation. It exists in much the same way as an ongoing simulation would, except that its time dimension isn't shared with the simulating universe. But every observer within has had the same observations as if it did.

Re:On the Nature of Time by skissane on Tuesday October 08, 2024 @07:17PM (#41782790)
This assumes that a map, if sufficiently detailed, is identical to the territory.

Maybe it is, maybe it isn’t - but it is a highly debatable metaphysical assumption. I’m not sure how seriously we should take some people’s claims that they “know” that such an assumption is actually true

Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:21PM (#41782818)
It's an argument about simulations, not about reality. If reality is a simulation, then arguments about simulations apply to it, but that's the big if.
Re:On the Nature of Time by skissane on Tuesday October 08, 2024 @07:47PM (#41783009)
Not necessarily. Suppose that consciousness/qualia/etc is “something extra” which has to be added to non-mental reality, as some dualists believe. Then, it would be possible that we live in a simulation which contains consciousness because that “something extra” has somehow been added to it. And yet, maybe the “much larger” universe which contains our simulation also contains such a “log book” of a very similar universe to our own, also containing intelligent life - and yet, if the “something extra” has not been added to that “log book”, it would lack consciousness and qualia, unlike our own universe.

I’m not arguing that a dualism (of this sort) is actually true, merely that we don’t (and can’t) know for a fact that it is false. But if we can’t know for a fact that it is false, then even if we (somehow) knew our reality was simulated, that wouldn’t give us grounds to make confident inferences about the nature of other simulations, or the nature of simulations in themselves

Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:55PM (#41783054)
I agree with your post. However, I was using the most mechanical meaning of simulation: "the production of a computer model of something, especially for the purpose of study," which implies determinism and excludes the "something extra."
Re:On the Nature of Time by skissane on Tuesday October 08, 2024 @09:35PM (#41783617)
It doesn’t actually exclude the “something extra”, it is neutral as to whether or not there is any “something extra”

Panpsychists claim everything is conscious, even rocks, even atoms. Again, I don’t claim this is true (I’d be rather shocked if I somehow found out it was), but we can’t know for a fact that it is false. Yet if panpsychism (or at least certain versions thereof) is true, every simulation (even a simulation of the weather, or of crop growth) is conscious, simply because absolutely everything is. But I don’t think most standard definitions of “simulation” are excluding that possibility - on the contrary, they are agnostic with respect to it, treating its truth or falsehood as outside of their scope

It also doesn’t necessarily imply determinism because some computer simulations use RNGs. Most commonly people use pseudorandom RNGs for this, but there is nothing in principle stopping someone from replacing the pseudorandom RNG with a hardware RNG based on some quantum mechanical process, such that it is indeterministic for all practical purposes, and the question of whether it is ultimately deterministic or indeterministic depends on controversial questions about QM to which nobody knows the answers

Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @09:59PM (#41783732)
> It doesn’t actually exclude the “something extra”, it is neutral as to whether or not there is any “something extra”

Roger, that's even better. I tried to clarify the log book idea in another reply.[1] The question is whether you can have reality (from the observer's perspective) just based on whether coherent information exists in any setting.

Basically the question is whether we can go from "I think, therefore I am" to "something is constructing information." The latter is obviously a simpler, lower-level proof than other concepts of existence.

That brings us back to the "something extra." Is it required for our observations to be possible, i.e. can we rule out the log book conjecture? I don't think we can, but I might be wrong.

[1] https://news.ycombinator.com/item?id=41783599

Re:On the Nature of Time by orangecat on Tuesday October 08, 2024 @10:26PM (#41783875)
And yet, maybe the “much larger” universe which contains our simulation also contains such a “log book” of a very similar universe to our own, also containing intelligent life - and yet, if the “something extra” has not been added to that “log book”, it would lack consciousness and qualia, unlike our own universe.

In that case, the non-conscious people in the log book would spend a lot of time pontificating on their experiences of consciousness and how mysterious it is and whether it's possible for there to be other universes that contain entities like themselves except not conscious. They'd be having these discussions for reasons that have nothing to do with actually being conscious, but coincidentally their statements would perfectly correspond with our actual perceptions of consciousness. Maybe not logically impossible, but it seems extremely improbable.

(This is pretty much the argument at https://www.lesswrong.com/posts/fdEWWr8St59bXLbQr/zombies-zo... which I find persuasive).

Re:On the Nature of Time by mistermann on Tuesday October 08, 2024 @07:29PM (#41782886)
The word "simulation" is it self a simulation. So is the word "is".

https://en.m.wikipedia.org/wiki/Semiotics

Reality is a multi-disciplinary domain, but it gives off the appearance of being physics only, because of its metaphysical nature.

Re:On the Nature of Time by FrustratedMonky on Tuesday October 08, 2024 @07:22PM (#41782831)
Except for the randomness introduced in Quantum Mechanics.

If they ever solve the randomness, then if the map is down to every particle, then yes, the map and reality could be the same. But think at that point you need a computer the size of reality to keep track of every particle.

Or, maybe the entire universe is one giant wave equation. But again, I think you need a computer the size of the universe to solve it.

Re:On the Nature of Time by skissane on Tuesday October 08, 2024 @07:53PM (#41783048)
We don’t know for a fact that QM contains irreducible indeterminism. If many worlds is true, then QM is ultimately deterministic. Same if hidden variables is true. A large class of local hidden variable theories have been ruled out by Bell’s theorem, but non-local hidden variable theories survive it (such as the Bohm interpretation and the transactional interpretation), as do local hidden variable theories which deny the Bell theorem’s assumptions about the nature of measurement, such as superdeterminist local hidden variable theories.
Re:On the Nature of Time by goatlover on Wednesday October 09, 2024 @12:29AM (#41784509)
An MWI universe would be hard to simulate though. There's an unknown vast number of branches.
Re:On the Nature of Time by zeven7 on Wednesday October 09, 2024 @03:47AM (#41785482)
Maybe with a quantum computer in a larger multi worlds universe?
Re:On the Nature of Time by FrustratedMonky on Wednesday October 09, 2024 @07:57AM (#41786899)
Wasn't the Noble prize last year for eliminating local hidden variables? That spooky action at a distance does occur?

And for many worlds. Doesn't it punt randomness into other universes, but doesn't help us solve for results in our own individual universe. Since we can't measure what happens in the other universe we don't really know. If there were two results, and one is in one universe, and one in our universe, sure we determinedly know both results. But we don't know which universe we are in, so instead of a random result, now we have 2 answers and 2 universes, but now randomly don't know where we are?

Re:On the Nature of Time by kaibee on Wednesday October 09, 2024 @12:23PM (#41789680)
> now we have 2 answers and 2 universes, but now randomly don't know where we are?

We are in both. Both universes are equally real. Each 'copy' of you knows it's in the universe where the result matches the observation.

Re:On the Nature of Time by FrustratedMonky on Wednesday October 09, 2024 @01:08PM (#41790197)
I'm pretty sure this is not true. Nobody has proven this.

If in my universe I could always predict the correct results, then we would just have determinism, and I could predict exactly when an atom would decay. There would be no need for statistics.

Some high level background that might help.

https://www.youtube.com/watch?v=z-syaCoqkZA

https://www.youtube.com/watch?v=433tAfO4dbA

https://www.youtube.com/watch?v=rvG1A795tqE

Re:On the Nature of Time by skissane on Wednesday October 09, 2024 @06:02PM (#41793178)
> Wasn't the Noble prize last year for eliminating local hidden variables? That spooky action at a distance does occur?

The 2022 Nobel Prize in Physics was for experimental verification of Bell's theorem. The experiment did not rule out superdeterministic local hidden variables; superdeterministic local hidden variables does not violate Bell's theorem, since Bell's theorem assumes "free will" (that there is no correlation between arbitrary choices made by an experimenter and the state of the system being measured), but superdeterminism is the denial of that assumption.

Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:29PM (#41782897)
Are you saying that some things are just not simulable, given a sufficiently large and powerful computer, or that the universe is or might be infinite?
Re:On the Nature of Time by FrustratedMonky on Tuesday October 08, 2024 @07:38PM (#41782955)
If the universe is real, not simulation.

If you know the position and speed, everything, about every particle, then you should be able to extrapolate the future by calculating it. The problem is you need a computer the size of the universe to do that calculation.

So even thought the map is the territory, equal scale, and you have the map. It is little worthless because the map ends up being reality.

Edit: Little different than the idea that if this is simulation, you can do clipping and only render what we see. I'm saying the entire universe is 'real'.

Re:On the Nature of Time by jorvi on Tuesday October 08, 2024 @08:11PM (#41783181)
> The problem is you need a computer the size of the universe to do that calculation.

I’m not sure were you get that idea from. The amount of calculations we can do, per say, 1 000 000 molecules dedicated to the calculation has absolutely skyrocketed, and will continue to skyrocket.

Re:On the Nature of Time by FrustratedMonky on Tuesday October 08, 2024 @08:19PM (#41783232)
"The amount of calculations we can do, per say, 1 000 000 molecules dedicated to the calculation "

Lets say it takes 100 molecules in a circuit to calculate 1 particles state. Then you already would need a universe 100X the size to calculate our 1X size universe.

I'm assuming all particles, not that this is somehow clipping and only rendering what we see. I'm not talking about the brain in box simulation, I'm talking about idea that entire universe is out there. What would it take to calculate every position of every particle.

Re:On the Nature of Time by jorvi on Wednesday October 09, 2024 @07:19AM (#41786615)
> Lets say it takes 100 molecules in a circuit to calculate 1 particles state. Then you already would need a universe 100X the size to calculate our 1X size universe.

That’s not how it works though. You’d have a lot of fixed costs to build a computer that simulates exactly the behavior of one particle. But then simulating a secondary particle will have a much, much, much smaller marginal cost.

Since you brought up clipping, games are actually a perfect example. You can see games as very crude simulations of our own reality, or slices of it. Take for example Red Dead Redemption 2. Run it on a PS5. Now compare the size of your PS5 to the mass of what was the old Wild West territory :)

Plus there’s the whole quantum computing thing, where in a way you’re reaching into “alternate” realities for extra compute.

Re:On the Nature of Time by FrustratedMonky on Wednesday October 09, 2024 @08:06AM (#41786972)
Yes. Just like a Minecraft World is like the size of 64,000 Earths, but it runs on my laptop.

That is what I'm saying is not happening. I'm saying that in a particle collider, we measure particles, and those exist all the time, not just when we are looking at them. Like, I have DNA and bones, they exist all the time, not just a simulation showing a 'skin' so it doesn't have to render everything.

Unless you are making a bigger point. That a computer that could be simulating every single particle, must exist outside this universe, and maybe mass and energy in this outside universe is so radically different we can't even grasp the scales of it.

Just like someone inside a minecraft world with blocks, couldn't grasp the amount of energy in our world.

Re:On the Nature of Time by jorvi on Wednesday October 09, 2024 @12:29PM (#41789752)
Well, I don’t know about outside the universe, but you’re still not understanding how scaling works. And our technological progress.

The simplest way I can put it is that at some point of compute, there is a crossover where you need less mass to simulate something than the mass of the actual thing is. This will hold true for particle simulations as well. So no, you would not need more particles than the universe has to simulate the universe perfectly.

Re:On the Nature of Time by FrustratedMonky on Wednesday October 09, 2024 @12:54PM (#41790042)
Ok. I'll try again. I think the 'scaling' issue here is not understanding the size of the scale if we are talking about if dealing with every particle in the universe. The largest super computers today aren't simulating every particle in even a few molecules.

So lets say you have Minecraft running.

You can completely build a CPU / Memory, etc... Inside Minecraft with Redstone.

Lets say you do this, build a PC inside Minecraft to the point that it is functional enough to run Minecraft. Minecraft running in Minecraft.

There is huge overhead.

You need an astronomically large real PC that could handle running Minecraft such that the Minecraft version running inside Minecraft is usable. That is the scale problem.

I'd have to dig up the citation. But pretty sure this compute power needed to compute the universe has been worked out.

Re:On the Nature of Time by jorvi on Thursday October 10, 2024 @08:32AM (#41798173)
> Ok. I'll try again. I think the 'scaling' issue here is not understanding the size of the scale if we are talking about if dealing with every particle in the universe. The largest super computers today aren't simulating every particle in even a few molecules.

So.. we are basically just a few meters over the start line in terms of doing perfect particle simulations :)

Look at protein folding. For decades, we could do it incrementally faster as our globally available compute increased. Then Alphafold came along and proved that it could be done much more efficiently. Now there's multiple models / companies that are planning to jostle for supremacy in that space.

Our ways of simulating particles will get more sophisticated and efficient as time goes on. Our hardware will push more calculations per watt and per density (aka per unit of mass).

I guess ultimately you take the pessimistic view and I take the optimistic view, so we'll have to agree to disagree. Good talk though!

Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:46PM (#41783002)
If the universe is not infinite, and if individual particles and waves are calculable, it follows that one can postulate a larger universe capable of simulating it, or a large enough log book in this example.

What I find interesting is looking at whether some observable things look like they might be performance optimizations, or even "magic seeds" (as in RNG seeds.)

No proof of a simulation obviously, but maybe hints.

Re:On the Nature of Time by tines on Tuesday October 08, 2024 @07:46PM (#41782996)
> If you know the position and speed, everything, about every particle, then you should be able to extrapolate the future by calculating it.

But isn't that the exact thing that quantum mechanics refutes? You cannot know the future just from the past; you can only know the probabilities of different futures.

Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:58PM (#41783075)
OK, but if you own the machine, you can just pick the outcome you want, or draw it from the distributions at random. We (observers inside the machine) cannot know the future of course.
Re:On the Nature of Time by FrustratedMonky on Tuesday October 08, 2024 @07:57PM (#41783069)
Yes. I referred to the randomness that would prevent this, "once that is solved".

Guess I'm in the camp that eventually we'll find some model or discover something new, to discover what is behind the randomness, so it is no longer just random. But, yes, that is big IF.

Until then, with current theories, we couldn't do these calculations. They'd just be approximations accounting for some randomness.

Re:On the Nature of Time by Filligree on Tuesday October 08, 2024 @09:33PM (#41783600)
Many-Worlds doesn’t contain or require any randomness.

I guess for whatever reason you don’t consider that to be the correct discovery?

Re:On the Nature of Time by FrustratedMonky on Wednesday October 09, 2024 @07:49AM (#41786836)
Because it doesn't remove the randomness from our universe. It punts it to other universes. That is great, but doesn't allow us to predict things in our individual universe.

Or another way of saying it. We have 2 answers, they are determined. That is great, we know the 2 answers, one in each universe. Now the problem is we don't know what universe we are in. Now which universe we are in is random.

We didn't move the ball towards doing something useful in our own universe.

Re:On the Nature of Time by Filligree on Wednesday October 09, 2024 @08:22AM (#41787094)
The 'universes' are loose abstractions, not a defined part of the theory; there's no actual hard distinction between timelines, in much the same way as coastlines don't have a defined length. They all blend into each other if you look closely enough.

That said, isn't the obvious answer 'all of them'?

Re:On the Nature of Time by partomniscient on Wednesday October 09, 2024 @08:40AM (#41787270)
I am King Ozymandias look upon my complete data dump/backup*, ye mighty and despair!

*May be subject to entropy over time.

Re:On the Nature of Time by amelius on Tuesday October 08, 2024 @07:27PM (#41782873)
If I took the binary representation of that log and XOR'ed it with a random binary string, then would the result also have observers with the same observations?
Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @07:33PM (#41782922)
Good question? :) I'd say no.

How about an exact copy of the log book, but with one bit flipped. Voila, mostly universal physics.

Re:On the Nature of Time by kouru225 on Tuesday October 08, 2024 @09:12PM (#41783498)
Ok but the act of writing it down would always take longer than the actual unfolding of the universe itself. Just like the halting problem, we can’t skip ahead at any point and we have no idea what will come next.
Re:On the Nature of Time by worstspotgain on Tuesday October 08, 2024 @09:33PM (#41783599)
Sure, but the timebases are different. Maybe it took the butterflypeople a thousand butterflyweeks to write it out.

Let me restate the metaphysics a bit differently. Let's say there's no us, no butterflypeople, nothing at all. Entropy reigns supreme, no information is organized.

Now add the butterflypeople. They write the humanpeople's log book. Information exists in organized form. The humanpeople's bits have been divined out of the great entropic nothing. Maybe that's all it takes?

Re:On the Nature of Time by garaetjjte on Tuesday October 08, 2024 @09:47PM (#41783671)
Reminds me of https://xkcd.com/505/
Re:On the Nature of Time by julianeon on Wednesday October 09, 2024 @12:49AM (#41784601)
There's a hidden condition here.

How do you know every event to every particle?

The answer to that will literally change what gets written in the log book.

Re:On the Nature of Time by kridsdale3 on Wednesday October 09, 2024 @01:32AM (#41784793)
The point is the log is a graph or a tree, not an array.
Re:On the Nature of Time by throw310822 on Wednesday October 09, 2024 @02:33AM (#41785109)
Now shred that log to particles and scatter them everywhere, and you have the "dust theory". Neither the time dimension or the log are shared with the simulating universe, and yet they are still valid for the observers within the universe.

If the sequence of the log states is entirely deterministic based on the initial state, then you don't even need to actually write down the entire log for it to "exist". This is Greg Egan's Permutation City.

Re:On the Nature of Time by worstspotgain on Wednesday October 09, 2024 @03:38AM (#41785442)
Can we reduce this to an estimate of survivorship bias? If there is only one universe, then our survival is clearly explained: we're in the only reality there is. If all possible universes exist, then we really lucked out in ending up in this one (well, depending on who wins the election I guess.)

In the middle are the permutations selected through the filter of other realities, when they chose which universes to simulate. We lucked out but not as much, because uninteresting universes never made it out of the entropic soup.

It would have to be a conditional estimate of course, because our sentience biases our contemplation.

Re:On the Nature of Time by oersted on Wednesday October 09, 2024 @02:34AM (#41785115)
Quick appreciation for the Douglas Adams reference :)
Re:On the Nature of Time by buginprod on Wednesday October 09, 2024 @02:58AM (#41785235)
Randall has you covered: https://xkcd.com/505/
Re:On the Nature of Time by nonameiguess on Wednesday October 09, 2024 @01:11PM (#41790229)
This kind of thought experiment seems like it breaks down due to the uncertainty principle. We can't exactly specify the full state of every particle in the universe. The universe might also be infinite and you can't enumerate an infinite set even without uncertainty, though you can write a generating function or recurrence relation for it, which seems to be Wolfram's point.

But why bother with this kind of detail? What's the difference between what you're imagining here and a normal reel of film? It can be played back, but even if it isn't, it records the state of events that happened, including observers that once existed and no longer do, experiencing events that once happened but no longer do. It's possible for a record to describe a canonical sequence even if the record itself doesn't change. Somebody outside of the record can view it out of order, speed it up, slow it down, pause it, reverse it. A film reel doesn't share the time dimension of its own universe in that way.

I'm struggling to come up with what this implies and why.

Re:On the Nature of Time by worstspotgain on Wednesday October 09, 2024 @03:44PM (#41791855)
To your first point, if it's a simulated universe, the simulators can just choose to make it finite, and come up with their preferred particle behavior rules.

As observers, we perceive time as passing, but is there anything special in this perception? Looked at another way, everything could be frozen in a 4D log book and we couldn't tell the difference, or could we? In this interpretation, Napoleon is as alive (in 1820) as we are (in 2024.) A film reel is a similar concept, except it's just a 3D projection rather than a complete detailed 4D account.

Re:On the Nature of Time by nonameiguess on Wednesday October 09, 2024 @05:33PM (#41792908)
I get the questions of eternalism, the reality of the past and future, why privilege the present (or at least my present), and all that. I just don't understand why the fact that you can record events in a medium that doesn't experience the time that it records has any implications for how we should think about this.

Whether or not you want to say "Napoleon exists" or "Napoleon existed" seems to be a matter of linguistic convention and the more common latter would reflect speakers privileging their own time. If you want to look at it another way, Napoleon exists, but entirely in my past light cone, and I exist entirely in his future light cone. I can't send him any kind of information, but he can send information to me. Is there anything special in this perception? To who? To observers at the absolute end of all time, my future is just as written in stone as Napoleon's. To observers I can receive information from, my future is unknown.

To any particular observer, there are regions of spacetime in which you have no past. There are regions in which you have no future. There is a region in which you have both a past and a future. Is there anything "special" in perceiving the sequence of events within the third region as passing rather than existing forever as a log? Not really. You're just describing a different variety of the Copernican principle or relativity as far as I can tell. But so what? None of us are the center of the univers. None of us exist in a special inertial frame describing absolute spacetime. These facts, however, have consequences in terms of how to measure and compute stuff. They change the kind of testable predictions you make given certain conditions. What computational or predictive consequences arise from observing that the entire world curve of the universe exists at once from a perspective outside of the universe? Going back to the I can't send information to Napoleon thing, if observers outside of our universe are keeping a log, none of us nor anything else in our universe can receive information from them, so what difference does it make?

It's an interesting shower thought but kind of also a big so what?

Re:On the Nature of Time by worstspotgain on Wednesday October 09, 2024 @08:01PM (#41794145)
One way the simulation argument starts is: Is this the ultimate nature of reality? A universe out of thin void? One possibility is that all possible universes exist, we just have survivorship bias. But we're blessed with poetry and rainbows and Goldilocks constants, which seems like a very lucky draw.

So we proceed to wonder if it's a simulation. That would mean the universe is interesting because it was designed or selected as such. This answers some local questions, and punts the existentialism into the simulating world.

My argument is that a simulation need not look like the Matrix, where there's a machine running in real time so that the simulating and simulated universes share a timeline. The simulants might just be doing the relevant computations in whatever graph-traversing order, and printing them out or whatever.

The computed information would make up our universe, it would be the essence of it. The universe would have come into "being" just by being selected out of the big entropic soup of all possible 4D log books to write.

As for "so what," it's just amateur philosophy, no guarantee you'll find it interesting.

Re:On the Nature of Time by jiggawatts on Wednesday October 09, 2024 @10:34PM (#41794929)
A fun variant of this is that the log can be taken at variable intervals and as long as it is sufficiently detailed, it can still capture all salient details.

Similarly a simulation run at some "tick rate" can also be run at 2x the rate while taking 1/2 the step per tick. Within the universe nobody would notice, as long as the steps were fine enough to begin with.

I think it was in Diaspora (or Permutation City?) that Greg Egan proposed that any tick rate would be unnoticable to that simulated beings, including "none".

In other words, the movie Top Gun will continue to exist as-is, no matter how many copies are made of it, including none. Encoded as a digital file it is just a number, a pure timeless concept, it doesn't have to be written down to exist. It always existed on the number line, even before Tom Cruise was born. In fact, every encoding of Top Gun exists on the number line, in every compression format, in every resolution, even a future 16K resolution that was never filmed and has no display devices made for it yet. Its encoding as a 400GB long number is there, already, and will always be there.

In other words, and simulation, an log of events, any experience already exists in mathematics, in every encoding... somewhere on the number line. This includes the entire physical universe. This isn't hypothetical, it's necessarily true! Anything that can be represented by a finite amount of information must be on the number line.

Even if you assume the Universe lasts forever, you can break its history up into a sequence of states, each of which is finite. Then the series will exists on the number line as a set of points heading off to infinity.