I'm reading David Chalmers' Reality Plus. His main thesis is the following: If we found out, say, that we lived in some kind of Matrix scenario, we shouldn't then conclude that everything is unreal or just a hallucination. The right conclusion is that the stuff we see and interact with wasn't made the way we thought it was made. I thought the chair I'm sitting on right now was made of atoms, created through natural processes inside stars, but it's actually made of bytes, and programmed by someone in a computer. That's a massive discovery to be sure, but it's different from discovering that everything is unreal or just a hallucination.
I won't recap or review the whole book in this blog post - instead, I'll ponder a question that popped up while reading:
Why have demons fallen out of fashion? Why is it all about computer simulations these days?
Everyone who's taken a philosophy class knows about Descartes' Evil Demon thought experiment. What if I'm completely mistaken about the world, because my sensory impressions are actually caused by an Evil Demon who keeps feeding me inaccurate information? Perhaps it distorts my very thoughts? Descartes thought he could still be certain that he existed (at least as a thinking being), because if he didn't exist, he wouldn't be able to doubt anything either. But the Evil Demon scenario is meant to throw doubt on most of our knowledge. I think I know, not just that I exist, but also that I'm sitting on a chair typing on my computer right now. But perhaps that's just part of an all-encompassing demon-induced hallucination! (Or, on Chalmers interpretation, the sensory-world that the Demon creates is still real in its own way, but the Evil Demon thought experiment nevertheless gives me reason to doubt that the world works the way I thought it works.)
Descartes (in)famously provided a very unsatisfying "solution" to this problem of knowledge: if there really is a good and perfect God, He wouldn't deceive us like this. And God must exist, because unless perfection existed, we wouldn't be able to conjure up the idea of it. Therefore, we can trust that we're not subjected to this kind of large-scale deception.
The latter premise has been heavily criticized since Descartes made his argument, and Chalmers also pokes a hole in the former: Perhaps God, who works in mysterious ways and all that, has great reasons that we don't know of for creating a large-scale deception!
But this little blog post won't focus on Descartes critique, and I'm not an expert on his philosophy anyway.
There are precursors to Descartes' thought experiment throughout the history of philosophy. Ever since antiquity, there have been philosophers who argue that we are or at least might be radically mistaken about the nature of reality. But nowadays, such arguments usually invoke computer simulations. We've got the twentieth century Brain in a Vat scenario - basically like the Matrix, except people don't have entire bodies lying in pods, just disembodied brains. And we've got the more radical idea that we might not even be brains, but just (sentient, feeling, thinking) computer simulations. While reading Chalmers' book, it struck me that this is a curious shift.
I get the impression that philosophers nowadays prefer computer simulations to demons and other magical entities because it somehow seems more realistic. But is it? How would we even judge that?
Suppose I see some really weird phenomenon here in our world, like a dozen pink elephants walking on water across the Baltic sea. Suppose other people witness it too - say, sea captains and passangers on multiple vessels, pilots flying above, many other people - they all see the pink elephant procession before it disappears again. We rule out "hallucination", there's just no way that so many people could have the exact same hallucination at the exact same time. Even if it's possible to induce the same hallucination in a group of people, these are different groups, they had different food and drinks, they haven't been gathered together with a hypnotist who could have hypnotized all of them, there's nothing strange that scientists could detect in the air (and even if some hallucinatory gas had spread above the Baltic, it wouldn't give everyone the exact same sight), etc etc. So, after having ruled out mass hallucination, how should we explain the procession of pink elephants?
In this scenario, it seems more plausible to assume that the phenomenon was created via technological means, even if it's tech that's unknown to the vast majority of people. Maybe some tech company tested some amazing 3d hologram gizmo they just invented, but haven't told anyone of yet. Alternatively, we could assume that it was all magic. But unless we somehow manage to rule out the tech explanation, this seems more far-fetched. If we accept the magic explanation, we would have to radically revise well-established scientific theories. Better to assume, at least for the time being, that there's some new tech that abides by the laws of nature as we know them, even if we don't know how the tech works just yet. Occam's razor and all that.
However, the kind of thought experiments invoked in arguments for global scepticism are very different. They invite us to imagine that there's a kind of hyper universe, in which the world as we know it is generated.
Now, compare the following two scenarios:
1. The hyper-universe is radically unlike ours. Some kind of demon or deity continuously creates and runs the world as we know it via some process that we don't have words for (except "magic").
2. The hyper-universe is populated by humans, and all laws of nature we know about also holds.
Also, computer sims can be sentient. Actually, we have no idea if sentience somehow depends on brains or if it can be generated by computers, but in this second scenario, it can be computer-generated.
Also, the people of the hyper-universe have the extremely impressive tech and the resources required to simulate our whole universe, or at least as much of our universe as we can spot (that's still a lot).
Also, the people of this universe have some motivation for creating realistic simulated universes.
Maybe they have different ideas than us about what's entertaining to watch. In our world, neither highly commercial fiction, nor artsy fiction enjoyed by few, much resembles our real lives. Writers of biographies and autobiographies must pick and choose what to focus on, what to mention in passing and what to omit - no one would read them otherwise. But maybe the humans of the hyper universe enjoy a simulation which includes every single toilet visit and every instance of listless doomscrolling etc.
Maybe, despite being so much more technologically advanced than us, big computer simulations are still an important research tool for them (as opposed to them using scientific methods that we can't even imagine).
Maybe they have some other motivation.
Also...
Do we have any basis whatsoever for calling scenario 2 more plausible than scenario 1? Can we invoke Occam's razor in favour of scenario 2? The hyper-universe in scenario 2 is more similar to our own universe than the hyper-universe in scenario 1. Still, both scenarios invoke a whole extra universe. And, at least under some descriptions, scenario 2 requires us to make more additional assumptions than scenario 1.
This is just a blogpost. I won't pretend that it is of the same quality as a ready-to-go-to-peer-review philosophy paper. Perhaps there are still valid reasons to consider scenario 2 somehow less far-fetched, more plausible, than scenario 1 above. But I suspect that philosophers nowadays prefer 2 over 1 just because it seems "more sciency" to them, more science fiction and less fantasy. Which isn't actually a rational reason.
We should take scenario 1 as seriously as scenario 2. Maybe more so! There may be reasons as to why a universe that abides by all the laws of nature that we currently know of would be unable to support truly massive computer simulations with sentient sims. But a hyper-universe that is radically different from ours - well, it's in the nature of the thought experiment that we don't have any reason to deny its possibility.
