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Constraints on the Universe as a Numerical Simulation (2012)

arxiv.org

131–140 of 178 posts

Re: Constraints on the Universe as a Numerical Simulation (2012)

#131
post #75
post #70

Earlier quoted context omitted.

I'm not sure I buy into that, because we haven't been able to draw a strict line between what a "player" and "npc" would potentially be.

Players = gods. NPC = rest of us.

The players are those lucky few that have an internal voice and their own agency. They can do almost whatever they want, as long as they can figure out how.

NPCs are more like walking zombies and have to fill the role they were born into.

Re: Constraints on the Universe as a Numerical Simulation (2012)

#132
post #112
post #93

Earlier quoted context omitted.

You can change symbols all you want, but when life appears in your simulation they won't care. If they put 2 items and then another 2 items, and 4 items are there - for all they care 2+2=4. And if sometimes its 5 - they will do what we did with relativity when it turned out velocities doesn't add up like they "should". We haven't changed addition - we changed the equations used in physics. I guess you could hand-made…

If you put 2 male mice in a box with 2 female mice and wait a while, you may find 5 or more mice in the box. Or if you put 2 clouds in a box and later put 2 clouds in the box, you probably won't find 4 or 5 clouds in the box. The act of putting things in boxes (after first perceiving and classifying them as discrete entities) and the abstract notion of addition are only as related as you need them to be for a given p…

> The act of putting things in boxes (after first perceiving and classifying them as discrete entities) and the abstract notion of addition are only as related as you need them to be for a given purpose.

Yes. That was my point. How would you change the abstract notion invented by creatures in your simulation if not by changing reality to shape their abstractions? And how do you change enough instances that their math develops in such way that 2+2=5?

I think our basic math (logic, set theory, integer math) with some exceptions (choice theorem) is the only useful consistent basic math there is.

Re: Constraints on the Universe as a Numerical Simulation (2012)

#134
> At fixed quark masses, the CRR of a lattice ensemble generation (in units of petaFLOP-years) scales roughly as the dimensionless number...

The formula they give, indicates that the largest QCD calculations to date have taken 7.9e11 petaflop-years; this is consistent with the graph they give, but not with actual feasibility. What am I missing?

Re: Constraints on the Universe as a Numerical Simulation (2012)

#135

In my opinion this seems all pretty pointless. To be able to differentiate between a simulation and reality you have to know at least how one of those works in quite some detail. What if we discover floating point rounding errors in the laws of physics we observe? Who is to say that this is not a feature of reality? What if it is the other way round, what if we live in a simulation with laws of physics made out of re…

Not so pointless. Think that one of the NPC in a computer game gets intelligent. It could learn how to trigger bugs or cheats in the game or features thought only for the player. Examples: crash the game, which hopefully restarts from the last save. Get where no NPC was supposed to be, only players, and get teleported somewhere else. Trigger a stack overflow and perform actions in the host, maybe changing the program…

But how would that NPC know that it is in a game? What if we figured out how to do teleportation or time travel? How would you determine whether that is a feature of reality or whether we discovered a bug in a simulation?

Re: Constraints on the Universe as a Numerical Simulation (2012)

#136
post #86
post #80

Earlier quoted context omitted.

I see the distinction you're making (I think), but I still don't see how that invalidates GP's analogy. Surely "running" a wavefunction is computationally cheaper than re-evaluating the particle's characteristics at every universal frame. Perhaps it's not so much about our own "watching" but rather "do not calculate when irrelevant". My own analogy might be an online map frame like google maps, where tiles outside th…

The particle's characteristics ARE the wavefunction - or to say it another way, the wavefunction is the only real characteristic a particle has. When I run a quantum mechanics simulation at work, I might afterwards calculate the particle positions or some other classical characteristic of the system. But I need those characteristics only because I'm trying to get a classical model of the system. The system itself, wh…

> The particle's characteristics ARE the wavefunction - or to say it another way, the wavefunction is the only real characteristic a particle has.

As far as I know not in the De-Broglie-Bohm theory (but I'm not a physicist, so correct me if I'm wrong):

> https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory

> http://plato.stanford.edu/entries/qm-bohm/

> http://plato.stanford.edu/entries/qm-decoherence/#PilWavThe

Re: Constraints on the Universe as a Numerical Simulation (2012)

#137

Keep in mind that if you wanted to create a simulated universe you can ensure nobody ever finds out. If someone does find out, you can simply fix the problem and revert to a point in time just before the data leading to the discovery was captured. Speaking academically, you might be playing with fire if you probe the outer limits of the universe and we are in a simulation run by some entity concerned with keeping tha…

> Keep in mind that if you wanted to create a simulated universe you can ensure nobody ever finds out.

> If someone does find out, you can simply fix the problem and revert to a point in time just before the data leading to the discovery was captured.

Keep in mind that if you wanted to create an operating system, you can ensure that there are no kernel exploits.

If there is some kernel exploit, you can simply patch the kernel and reboot.

Re: Constraints on the Universe as a Numerical Simulation (2012)

#138
post #80
post #69

Earlier quoted context omitted.

This is a common misconception, but superposition has nothing to do with "do not render if the player is not watching." As far as we know, every particle in the universe is interacting with every other (with a light speed delay) and thus "measuring" it (modifying and responding to its wavefunction) at all times. In the two-slit experiment, for example, the wavefunction of a particle moving through a slit interacts wi…

I see the distinction you're making (I think), but I still don't see how that invalidates GP's analogy. Surely "running" a wavefunction is computationally cheaper than re-evaluating the particle's characteristics at every universal frame. Perhaps it's not so much about our own "watching" but rather "do not calculate when irrelevant". My own analogy might be an online map frame like google maps, where tiles outside th…

The computational problem of simulating a wavefunction is suspected by computer scientists to be exponentially harder than simulating classical physics (this is the question of whether BPP=BQP). So quantum physics is the opposite of a computational optimisation!

Re: Constraints on the Universe as a Numerical Simulation (2012)

#139
post #86

Earlier quoted context omitted.

The particle's characteristics ARE the wavefunction - or to say it another way, the wavefunction is the only real characteristic a particle has. When I run a quantum mechanics simulation at work, I might afterwards calculate the particle positions or some other classical characteristic of the system. But I need those characteristics only because I'm trying to get a classical model of the system. The system itself, wh…

> The particle's characteristics ARE the wavefunction - or to say it another way, the wavefunction is the only real characteristic a particle has. As far as I know not in the De-Broglie-Bohm theory (but I'm not a physicist, so correct me if I'm wrong): > https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory > http://plato.stanford.edu/entries/qm-bohm/ > http://plato.stanford.edu/entries/qm-decoherence/#PilWavT…

Yeah you're right, but in the De Broglie-Bohm theory the wavefunction is calculated, and then the movements of the particles are calculated on top. So from a computational perspective it's strictly harder.

Re: Constraints on the Universe as a Numerical Simulation (2012)

#140

Keep in mind that if you wanted to create a simulated universe you can ensure nobody ever finds out. If someone does find out, you can simply fix the problem and revert to a point in time just before the data leading to the discovery was captured. Speaking academically, you might be playing with fire if you probe the outer limits of the universe and we are in a simulation run by some entity concerned with keeping tha…

> Keep in mind that if you wanted to create a simulated universe you can ensure nobody ever finds out. > If someone does find out, you can simply fix the problem and revert to a point in time just before the data leading to the discovery was captured. Keep in mind that if you wanted to create an operating system, you can ensure that there are no kernel exploits. If there is some kernel exploit, you can simply patch t…

There are Operating systems without Kernel exploits, they are simply less efficient than modern OS's.
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