20 thoughts on “If We Are In A Computer Simulation”

  1. Were the physical laws of the universe designed to reduce the computational cost of the sim? If so, what aspects of the physical laws were designed to make computation cheaper?

    Random number generator on the quantum states. God may not play dice, but he flips a lot of coins.

  2. Were the physical laws of the universe designed to reduce the computational cost of the sim? If so, what aspects of the physical laws were designed to make computation cheaper?

    As I wrote in my review of Leonard Susskind’s “The Cosmic Landscape” it is precisely the nature of the physical laws we observe that causes me to believe it’s more likely than not that we’re in living in a simulation:

    Suppose this is the case: we’re inside a simulation designed by a freckle-faced superkid for extra credit in her fifth grade science class. Is this something we could discover, or must it, like so many aspects of Theory 2, be forever hidden from our scientific investigation? Surprisingly, this variety of Theory 1 is quite amenable to experiment: neither revelation nor faith is required. What would we expect to see if we inhabited a simulation? Well, there would probably be a discrete time step and granularity in position fixed by the time and position resolution of the simulation—check, and check: the Planck time and distance appear to behave this way in our universe. There would probably be an absolute speed limit to constrain the extent we could directly explore and impose a locality constraint on propagating updates throughout the simulation—check: speed of light. There would be a limit on the extent of the universe we could observe—check: the Hubble radius is an absolute horizon we cannot penetrate, and the last scattering surface of the cosmic background radiation limits electromagnetic observation to a still smaller radius. There would be a limit on the accuracy of physical measurements due to the finite precision of the computation in the simulation—check: Heisenberg uncertainty principle—and, as in games, randomness would be used as a fudge when precision limits were hit—check: quantum mechanics.

    Might we expect surprises as we subject our simulated universe to ever more precise scrutiny, perhaps even astonishing the being which programmed it with our cunning and deviousness (as the author of any software package has experienced at the hands of real-world users)? Who knows, we might run into round-off errors which “hit us like a ton of bricks”! Suppose there were some quantity, say, that was supposed to be exactly zero but, if you went and actually measured the geometry way out there near the edge and crunched the numbers, you found out it differed from zero in the 120th decimal place. Why, you might be as shocked as the naïve Perl programmer who ran the program “printf(“%.18f”, 0.2)” and was aghast when it printed “0.200000000000000011” until somebody explained that with about 56 bits of mantissa in IEEE double precision floating point, you only get about 17 decimal digits (log10 256) of precision. So, what does a round-off in the 120th digit imply? Not Theory 2, with its infinite number of infinitely reproducing infinite universes, but simply that our Theory 1 intelligent designer used 400 bit numbers (log2 10120) in the simulation and didn’t count on our noticing—remember you heard it here first, and if pointing this out causes the simulation to be turned off, sorry about that, folks!

    Here are some specific nagging little discrepancies in present-day experimental science which might be signatures of round-off.

  3. If we existed in a simulation, we’d eventually see some obvious breakdowns due to innate limitations in the model. We wouldn’t be able to see infinitely far in all directions, for example. There’d be some problems with propagating signals at high velocities. There’d be some low level “graininess” that prohibited us from measuring positions and momentum in arbitrarily fine detail.

    Isn’t that reassuring?

  4. Oh shucks, great minds running in the same gutter! Fie on thee, John Walker!

    Okay, if we lived in a simulation, you’d see different people having very similar thoughts! So there.

  5. This sounds like a new religion when you ask, “what computer is this simulation running on?” Biblically, some time in the future there will be a resurrection from the memorial tombs. In other words, the computer is god’s mind and during the resurrection he will recreate people from memory.

    A test for this would be if we determine some discrepancy at extreme resolutions that seems to go away with further testing. It would be trivial for god to add qubits to his registers to push the anomalies beyond the levels of resolution that revealed them.

    Personally I suspect the babe is right and C is not constant.

  6. Time to do a re-write of Philip Jose Farmer’s excellent “To Your Scattered Bodies Go” with simulation as the deep secret.

  7. If the universe is a simulation, then everything we know about computers is based on a simulation, which may have no more to do with the real world than a D&D simulation does. Believing in the Great Computer is much an act of faith as believing in the Great Lion.

  8. If it isn’t a simulation now, then it will likely be in the future. One we construct to download ourselves into. Which may be the answer to galactic exploration without FTL travel. Who cares if it takes 100k years to get someplace if you’re immortal operating in side your own world.

  9. Since there will always be limits on one’s epistemology, regardless of one’s actual universe (it’s like a modern anthropic principle, no?), that argument could be made anywhere. Thus, the probabilistic case is perhaps the most compelling. (And this, too, seems like an updated Boltzman’s brain problem.)

    However, I’ve never seen a convincing argument addressing the existential problem of “downloading minds” that wasn’t, at its core, mere sophistry. I’ll keep my substrate for as long as I can, thanks.

  10. It really doesn’t matter. If our universe is really all there is, or if all we perceive is merely a simulation contained within a larger reality, it makes zero difference. Either way, we’re only limited by the inherent rules and our imaginations.

  11. Who cares if it takes 100k years to get someplace if you’re immortal operating in side your own world.

    The guy looking for the eternal power socket?

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