Probing The Matrix: Is our universe simulated, and if so… by who?

Interpreting the universe as a computer simulation is perhaps the inevitable byproduct of living in the computer age. The question today is not whether we live inside a simulation, but rather — what does it want, and what compromises with regard to the welfare its inhabitants might have been made to get it? The first rudimentary experiments to poke it in the belly and see how it jiggles are just getting underway.

If it’s possible to hack the universe, then particle physicists must be its early phone phreakers. Fears, which turned out to exaggerated, were raised few years ago that a black hole might unwittingly be created inside the Large Hadron Collider. Arguably, it is more accurate to say that with the theories that prescribe the existence of subatomic particles that exist nowhere else in the known universe, these folks actually invent them, rather than just discover them. The fact that they then go out and literally create subatomic particles inside of these huge, specially built accelerators, raises a very real question — what is a subatomic particle? Is it the blip on the oscilloscope, or the whole accelerator itself?

The Matrix

High-energy astrophysicists study cosmic rays — the most energetic particles naturally produced by the universe, as opposed to high-energy particles in accelerators. They are believed to come from distant events, like supernova explosions, pulsars, and quasars, and are detected in the vicinity of Earth using satellite- or balloon-borne instruments. Scientists have accumulated a wealth of data about cosmic rays. It is therefore not surprising that a recent proposal entitled Constraints on the Universe as a Numerical Simulation [PDF] seeks to reveal the structure of the grid underlying the simulated universe, using measurements of the energy distribution of these particles.

After considerable theorizing, the authors determine that the distribution and direction of incoming cosmic rays at the highest energies can be used to derive a limit on the spacing of the grid. That is actually quite a bold statement. Fundamental limits to how small space can be divided have arisen in physics discussions before, particularly in reference to the Planck length, which is quantum mechanical in nature. Here the authors only consider a simulation of a very small region of space, on the order of just a few femtometers, and assume ordinary classical computation comprises the simulation — which is to say there is no quantum computing necessary.

Before any definite conclusions can be drawn from these observations, more complete measurements of cosmic rays need to be made for the simple reason that astrophysicists have yet to observe a firm upper bound to the cosmic ray energy spectrum — its “tail” dips above a certain energy, but it is still long and of unknown length. In other words, the more we continue to look for cosmic rays, the more we continue to find particles at ever higher energies, making plausible explanations for their existence all the more difficult.

If the universe is a simulation, why is it being simulated in the first place?

One thing to bear in mind is that what constitutes a “proof” under one set of assumptions may not be accepted as such under another. Mathematicians can convincingly show for example, that the square root of two is an irrational number by proving that the opposite idea is false. As Kurt Godel showed in his incompleteness theorem, undecidable statements can and will arise within any finite set of axioms. Depending on our particular axioms, the question of whether we live in a simulation could be provable, disprovable, or neither.

Assuming that an upper limit to cosmic ray energy is found or other methods of verification are uncovered, and the simulation is to some extent quantified, is it possible to ascertain the purpose of the simulation? If it might be said that we are carrying out some kind of computation — what computation? It is no great leap to suppose that any advanced civilization or individual would seek to simulate the unfolding of its own universe, how life came to be in that universe, and how the simulator itself came to be, perhaps even nested within another simulation.

So suppose we suggest our own axiom as follows — “the simulation seeks to maximize the richness of the environment in which minds might develop, interact and probe the constraints of their own simulation while at the same time minimizing the amount of suffering of the unfortunate among those that arise in that simulation.” While the simulators may have had good intentions and respect for life, it is impossible to deny that there is and has been non-negligible suffering in our simulation. Is an axiom such as this compatible with what we can now observe?

One way to view our present simulation in this light is to imagine it set in motion with incomplete knowledge of what would unfold when left to its own devices. Perhaps the simulators cannot, or have chosen not to observe or manipulate the simulation. The original simulators might have long since expired or otherwise become detached from the simulation, having exhausted their own energy supply in an open universe, or having collapsed to a singularity in a closed one, somehow managing to manipulate matter on a scale grand enough to accelerate the simulation beyond collapse.

You are The One

Another way to examine the simulation is through the calculus of extremes. An appeal to the extreme viewpoint of the solipsist – the belief that the only sure thing in the universe is your own mind — would address the problem of minimization of suffering because it can simply be denied. The only discomfort in existence would be one’s own. Why then might a simulator even bother with simulating the environment if the most interesting thing to simulate is a mind?

If in fact many solipsistic minds are simulated, each in their own isolated world, the computational complexity of the task would grow enormously, making it desirable to at some point to overlap the environments. We might then ask, where in this kind of arrangement do we fall?

One question a simulation might attempt to answer is what is the optimal number of minds to apply to the major problems of the universe. I.e. how to maximally extend and allocate its finite resources. In other words, do you want a just a few large, hyper-intelligent minds attacking the problem, or rather lots of smaller minds?

To have faith that every water molecule in the ocean is being perfectly simulated at this very moment, in the absence of observation, may be a testament to just how easy it is for our universe to simulate reality. The number of permissible states for an ocean’s atoms would seem near infinite compared to the those for the three-pound mass in our heads, but which is really easier to simulate? The movements of the ocean can easily be captured with principles and even laws which could vastly simplify the task. Perhaps one day we will find a way to test this kind of hypothesis.

The idea of setting up some kind of “glitch” detector to look for inconsistencies in the simulation has been raised, but it may be difficult to characterize exactly what a glitch would be. People have experiences all the time in the normal operation of their own brains which could just as well be interpreted as as glitch, but typically we do not define them as such. Whereas a seemingly vivid apparition of a long since loved one in the hallway at night may be experienced fully from the incidental stimulus of a few errant sounds, another person would no doubt interpret the situation in an entirely different way.

The question of the degree to which simulations and minds may overlap is a question for another day. We are just beginning to write the experiments that create the conclusions we might draw, in the manner of the particle physicist. Solipsistic inspection is certainly useful as a tool for thought experiments, but as a social strategy it can only be a failure and is largely discounted as such. The viewpoint does offer one subtle abode — there is evidence that other people age and in fact die, but for you, there is only evidence that you get older.

© 2012 ExtremeTech Probing The Matrix: Is our universe simulated, and if so… by who?