The classic problem of the external world presents an epistemic challenge forged by the skeptics: how do I know that what I seem to be experiencing as the external world is really real for real? Early skeptics claimed that what seems real might be a dream. Descartes upgraded the problem through his evil demon which used its powers to befuddle its victim. As technology progressed, philosophers presented the brain-in-a-vat scenarios and then moved on to more impressive virtual reality scenarios. One recent variation on this problem was made famous by Elon Musk: we are characters in a video game. This is a variation of the idea that this apparent reality is just a simulation. There is a strong inductive argument for the claim that this is a virtual world.

One stock argument for the simulation world  uses the form of statistical syllogism. It is statistical because it deals with statistics. It is a syllogism by definition: it has two premises and one conclusion. Generically, a statistical syllogism looks like this:

Premise 1: X% of As are Bs.

Premise 2: This is an A.

Conclusion: This is a B.

The strength of this argument depends on the percentage of As that are B. The higher the percentage, the stronger the argument. This makes sense: the more As that are Bs, the more reasonable it is that a specific A is a B.  Now, to the simulation argument.

Premise 1: Most worlds are simulated worlds.

Premise 2: This is a world.

Conclusion: This is a simulated world.

While “most” is vague, the argument is such that if its premises are true, then the conclusion is more likely to be true than not. Before embracing your virtuality, it is worth considering a similar argument:

Premise 1: Most organisms are bacteria.

Premise 2: You are an organism.

Conclusion: You are a bacterium.

Like the previous argument, the truth of the premises makes the conclusion more likely to be true than false. However, you are not a bacterium. This does not show that the argument itself is flawed. The reasoning is good, and any randomly selected  organism would most likely be a bacterium. Rather, it indicates that when considering the truth of a conclusion, one must consider the total evidence. That is, information about the specific A must be considered when deciding whether it is a B. In the bacteria example, there are facts about you that would count against the claim that you are a bacterium, such as the fact that you are a multicellular organism.

Turning back to the simulation argument, the same consideration applies. If it is true that most worlds are simulations, then any random world is more likely to be a simulation than not. However, the claim that this specific world is a simulation would require consideration of the total evidence: what evidence is there that this world is a simulation? This reverses the usual challenge of proving that the world is real by requiring evidence it is not real. At this point, there is little evidence that this is a simulation. Using the usual fiction examples, we do not seem to find glitches that would be best explained as programming bugs, we do not seem to encounter outsiders from reality, and we do not run into some sort of exit system (like the Star Trek holodeck). That said, all this is still consistent with the world being a simulation: it might be well programmed, the outsider might never be spotted (or never go into the system) and there might be no way out. At this point, the most reasonable position is that the simulation claim is at best on par with the claim that the world is real since all evidence is consistent with both views. There is, however, still the matter of the truth of the premises in the simulation argument.

The second premise seems true, whatever this is, it seems to be a world. As such, the first premise is the key. While the logic of the argument is good, if the premise is not plausible then it is not a good argument overall.

The first premise is usually supported by a now standard argument. The reasoning includes the claims that the real universe contains large numbers of civilizations, that many of these civilizations are advanced and that enough of these advanced civilizations create incredibly complex simulations of worlds. Alternatively, it could be claimed that there are only a few (or just one) advanced civilizations but that they create vast numbers of complex simulated worlds.

The easy and obvious problem with this sort of reasoning is that it involves making claims about an external real world to try to prove that this world is not real. If this world is claimed to not be real, there is no reason to think that what seems true of this world (that we are developing simulations) would be true of the real world (that they developed super simulations, one of which is our world).  Drawing inferences from what we think is a simulation to a greater reality would be like the intelligent inhabitants of a Pac Man world trying to draw inferences from their game to our world.

There is also the fact that it is simpler to accept that this world is real rather than making claims about a real world beyond this one. After all, the simulation hypothesis requires accepting a real world on top of our simulated world. Why not just have this be the real world?