One of the sick enjoyments of a philosophical argument is the ability to justify an absurd conclusion by a few, seemingly plausible premises. Unfortunately, this is also why philosophy majors tend to make good lawyers. A recent philosophical trend to take the academia by storm is the idea that the universe is likely a simulation. Since Descartes, philosophers could not rule out the possibility that reality is a dream. Largely through the work of Nick Bostrom, however, some philosophers are now taking seriously the idea that the universe is likely a matrix.
The likelihood that we live in a computer simulation is not embedded in the kooky equations of string theory. Rather, the conclusion can be reached by pure a priori reasoning. What makes the simulation argument so attractive is that it reaches the conclusion that the universe is likely a matrix by a few, seemingly plausible premises. The simulation argument takes the following: Consciousness is the result of information processing at the level of the brain. Future, advanced civilizations will create simulations of the past in the same way we create simulations of the Sims. Last—and here is the kicker—simulated universes outnumber actual universes. Therefore, it is more likely we live in a simulated universe than an actual universe. QED.
The conclusion is indeed absurd. However, pinpointing where the simulation argument goes awry is surprisingly difficult. One move that could be made is to deny that consciousness is capable of being artificially simulated. Whether or not consciousness is capable of being downloaded is a hotly contested issue by artificial intelligence theorists that cannot be done justice to within the confinements of this article. Nevertheless, it is at least conceivable that one day, engineers will be able to create an artificial neuron made of silicon capable of performing the in-put and out-put tasks of a biological neuron. A mad neurosurgeon could slowly pick away a patient’s neurons, while replacing them with artificial neurons without altering their conscious experience. Since it is at least conceivable such a procedure could be performed, let us assume for the sake of argument that consciousness is capable of being simulated.
So where else might the simulation argument go awry? Another move that could be made is that it is unlikely a civilization could become so technologically advanced without first self-annihilating. Yet this move largely depends upon whether the universe is infinite. If the universe is infinite but contains only a finite number of atoms, then there are only a finite number of ways to assemble those atoms. Therefore, somewhere out in the infinity of space is an exact replica of the Earth and its denizens. If the universe is finite in size, however, then the probability that a civilization would become technologically advanced without first self-annihilating is low.
The question boils down to, is the universe infinite? As of right now, the only theory that is capable of explaining the locked uniformity of the cosmic microwave background radiation left over from the big bang is the theory of inflation which in turn, predicts the universe to be spatially infinite. However, if the simulated universe is a replica of an infinite universe, then there is no way of determining whether it is more probable that we are one of the infinite civilizations in the actual universe, or one of the infinite civilizations in a simulated universe!
What other features might we expect a simulated universe to take? One feature we might expect is that the constants of physics do not vary considerably. This is because the constants of physics cannot be expressed as irrational numbers (an irrational number is a number that cannot be represented, since its decimal representation extends to infinity). Irrational numbers, as far as we can tell, cannot be fully represented in a computer. In fact, computers contain safety guards from infinity loops that can hang up the system. An advanced civilization might simulate the constants of physics up to an arbitrary cut-off point at say, one-hundred decimal places. Yet the observed constants of physics in our own universe do vary considerably (pi is a common example). Therefore, we have positive evidence that the universe is not a simulation. All this in the infinite round, we can now sleep peacefully at night with the knowledge that the universe is likely not a computer simulation. QED.
By Nathan Cranford