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.
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.
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.
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.
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.
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.
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!
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.
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.
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.
I guess for whatever reason you don’t consider that to be the correct discovery?
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.
That said, isn't the obvious answer 'all of them'?
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'.