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I've never understood this argument in the context of this discussion. Why would the constraints of the simulation apply to that which is running the simulatio

by dwrowe 10y ago

I've never understood this argument in the context of this discussion. Why would the constraints of the simulation apply to that which is running the simulation?

michaelfeathers 10y ago
Exactly.
- fallingfrog 10y ago
  OK, there are lots of people here insisting that you can simulate a larger machine inside of a smaller machine, in terms of the total state space. Let me assure you that in general, you cannot. That's absolutely a fact. Windows can fool you into thinking it can simulate a 20GB system inside a 10GB system, because it's using the hard drive as the extra 10GB. Which means you really still have a 20GB+ simulating system! I'm talking about a system in which you don't have some other form of memory to fall back on. Data cannot be infinitely compressed, and state space is finite no matter how it's partitioned into dimensions and so forth.
  - JoeAltmaier 10y ago
    Still simulation means you may not have to represent every particle/state but can instead estimate. Or even not represent them at all until they are observed. Like a graphical system renders only what's in front of the camera. So the effective universe size could be enormous and use fewer resources than is apparent.
    - fallingfrog 10y ago
      Actually, the opposite is true. Read this great explanation by Richard Feynman: https://people.eecs.berkeley.edu/~christos/classics/Feynman.pdf https://people.eecs.berkeley.edu/~christos/classics/Feynman....
fallingfrog 10y ago
You can't write a virtual machine with 20 GB of memory running on a real machine with only 10. Simulation isn't magic.
- dwrowe 10y ago
  I'm not understanding your point - which may be completely on me - but your example here - why would the "child" universe require more memory than the parent has available?
  - JoeAltmaier 10y ago
    On my computer, I can write 2D simulations, or 1D. Or even 4D or 5D. The simulated universe doesn't have to have any relation to the host one.
    - fallingfrog 10y ago
      That's magical thinking. I was referring to the total simulated state space, which does not depend on the number of dimensions or any other parameter of the simulation.
      - JoeAltmaier 10y ago
        Not sure that sentence means anything. Of course the dimensionality has everything to do with the state space. It grows, by definition, geometrically with the number of dimensions.
        fallingfrog 10y ago
        If your state space is 16 bits, then you can create a 4x4 2-dimensional space or a 2x2x2x2 4-dimensional space, but the total space is still 16 bits. You cannot simulate a 32-bit state space on a machine with only 16 bits of memory, regardless of how many dimensions the simulated space has.

by dwrowe 10y ago

I've never understood this argument in the context of this discussion. Why would the constraints of the simulation apply to that which is running the simulation?

michaelfeathers 10y ago

Exactly.

fallingfrog 10y ago
OK, there are lots of people here insisting that you can simulate a larger machine inside of a smaller machine, in terms of the total state space. Let me assure you that in general, you cannot. That's absolutely a fact. Windows can fool you into thinking it can simulate a 20GB system inside a 10GB system, because it's using the hard drive as the extra 10GB. Which means you really still have a 20GB+ simulating system! I'm talking about a system in which you don't have some other form of memory to fall back on. Data cannot be infinitely compressed, and state space is finite no matter how it's partitioned into dimensions and so forth.
- JoeAltmaier 10y ago
  Still simulation means you may not have to represent every particle/state but can instead estimate. Or even not represent them at all until they are observed. Like a graphical system renders only what's in front of the camera. So the effective universe size could be enormous and use fewer resources than is apparent.
  - fallingfrog 10y ago
    Actually, the opposite is true. Read this great explanation by Richard Feynman: https://people.eecs.berkeley.edu/~christos/classics/Feynman.pdf https://people.eecs.berkeley.edu/~christos/classics/Feynman....

fallingfrog 10y ago

You can't write a virtual machine with 20 GB of memory running on a real machine with only 10. Simulation isn't magic.

dwrowe 10y ago
I'm not understanding your point - which may be completely on me - but your example here - why would the "child" universe require more memory than the parent has available?
- JoeAltmaier 10y ago
  On my computer, I can write 2D simulations, or 1D. Or even 4D or 5D. The simulated universe doesn't have to have any relation to the host one.
  - fallingfrog 10y ago
    That's magical thinking. I was referring to the total simulated state space, which does not depend on the number of dimensions or any other parameter of the simulation.
    - JoeAltmaier 10y ago
      Not sure that sentence means anything. Of course the dimensionality has everything to do with the state space. It grows, by definition, geometrically with the number of dimensions.
      - fallingfrog 10y ago
        If your state space is 16 bits, then you can create a 4x4 2-dimensional space or a 2x2x2x2 4-dimensional space, but the total space is still 16 bits. You cannot simulate a 32-bit state space on a machine with only 16 bits of memory, regardless of how many dimensions the simulated space has.