- The simulation argument was first put forth in a paper published in 2003 by philosopher Nick Bostrom.
- Bostrom assigns less than a 50 percent probability that we're living in a simulated universe.
- Some physicists believe that we can test this scientifically.
Are we living in a simulation? This idea has been explored on a number of levels. While there has been a fair share of sophomoric musings and half-baked proposals surrounding the hypothesis — usually in hazy podcast studios and college dorm rooms — there are actually a number of respectable contemporary philosophers and physicists who are seriously considering the idea and its implications.
The argument as we know it today first popped up in a paper by Swedish philosopher Nick Bostrom. Who argued both for and against the proposition of a simulated universe and then explored a number of consequences that flow from that proposal. His main points appear at the start of the argument, in which Bostrom states at least one of the following are true:
- The human species is very likely to go extinct before reaching a “post-human” stage.
- Any post-human civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof).
- We are almost certainly living in a computer simulation.
Bostrom calls this the Trilemma. We’ll be revisiting these points as we explore the arguments supporting that we live in a matrix-esque simulation and arguments that refute the idea.
Nick Bostrom’s trilemma
Bostrom is undecided on the true validity of the simulation theory, but he is one of the major proponents of the argument for it. Here are some of his arguments for the idea that we might be living in a simulation. He believes that there is a significant chance that there will one day be post-human entities with the possibility to create an ancestor simulation, unless we’re already in that simulation.
Bostrom accepts the simulation argument, but rejects the simulation hypothesis. Meaning that he thinks that one of the three possibilities is true, but he’s not entirely convinced we are in the simulation. He states:
“Personally, I assign less than 50 percent probability to the simulation hypothesis — rather something like in 20 percent-region, perhaps, maybe. However, this estimate is a subjective personal opinion and is not part of the simulation argument. My reason is that I believe that we lack strong evidence for or against any of the three disjuncts (1) – (3), so it makes sense to assign each of them a significant probability.”
He goes on to say that although some accept the simulation argument, their reasons for doing so differ in a number of ways. Bostrom is quick to point out that this is not a variant of Descartes famous demon hallucination brain-in-vat thought experiment
” … the simulation argument is fundamentally different from these traditional philosophical arguments… The purpose of the simulation argument is different: not to set up a skeptical problem as a challenge to epistemological theories and common sense, but rather to argue that we have interesting empirical reasons to believe that a certain disjunctive claim about the world is true.”
His simulation argument depends on hypothetical future technological capabilities and their use in the creation of a perfectly simulated universe and world, which would include our minds and experiences of what we consider reality.
Have we discovered the rules of the simulation?
In a far ranging and elucidating discussion a few years back at the Isaac Asimov memorial debate, Max Tegmark, cosmologist from MIT put forth a few arguments on the nature of the simulation in comparison to a video game.
If I were a character in a computer game, I would also discover eventually that the rules seemed completely rigid and mathematical. That just reflects the computer code in which it was written.
His point was that it seems like the fundamental laws of physics will eventually grant us the capability to create increasingly more powerful computers, far beyond our current capacity. These things could be the size of solar systems, perhaps even galaxies. With that much theoretical computing power, we could easily simulate minds if in fact that’s not already our fate.
Now under the supposition that we’re already in a super complex system emanating from some galaxy-sized computers, some detractors have said that we should be able then to spot “glitches in the Matrix.”
Bostrom was quick to point out that any glitch we considered real could just be frailties of our mind. That would include things such as hallucinations, illusions, and other types of psychiatric problems. If any kind of glitch occurred, which is expected in a computing system, Bostrom feels that the hypothetical simulators would be able to account for that by:
“… having the ability to prevent these simulated creatures from noticing anomalies in the simulation. This could be done by avoiding anomalies altogether, or preventing them from having noticeable macroscopic ramification, or by retrospectively editing the brain states of observers who had happened to witness something suspicious. If the simulators don’t want us to know that we are simulated, they could easily prevent us from finding out.”
He goes on to consider how this isn’t that far-fetched as our organic brains already do such a thing. While in the midst of a fantastical dream, we are usually left unaware of the fact we’re dreaming and this simple function is carried out by our technologically-unaided brain.
Testing the simulation hypothesis experimentally
Zohreh Davoudi, a physicist at the University of Maryland, believes that we can test if we’re in a simulation.
“If there is an underlying simulation of the universe that has the problem of finite computational resources, just as we do, then the laws of physics have to be put on a finite set of points in a finite volume… Then we go back and see what kind of signatures we find that tell us we started from non-continuous spacetime.”
The evidence that would prove we are living in a simulation could come from a unusual distribution of cosmic rays hitting Earth and suggesting that spacetime is not continuous, but instead made up of discrete points. Although the problem of proving you’re in simulation still has the implication that any proof found might also be simulated.
In a continued discussion of the subject at the Asimov’s conference, Davoudi brings up an old theological point with an up-to-date and modern premise.
“… What’s called the simulation is you just input the laws of physics, and nature and universe emerges. You don’t actually try to make it look like it’s something going on. You don’t try to — the same as with computer games. You don’t interfere with what you’ve created. You just input something that is very fundamental and just let it go, just as our universe.”
Other commentators remarked on this ideas similarity to deism. This means that “god” or deus was the first cause to set the creation of universe in motion, but doesn’t interfere in it afterwards..
From the simplicity of these laws of physics then emerges complex processes which seem to have continued to grow and evolve as the universe ages.
Arguments against the simulation theory
Theoretical Physicist, Sabine Hossenfelder, from Goethe University Frankfurt is in the camp that believes that the simulation hypothesis is just plain malarky. She argued in a blog post that a good deal of physicists don’t take this problem seriously. Hossenfelder also has problems with the nature of the argument and the way the theory is presented. She says:
“Proclaiming that ‘the programmer did it’ doesn’t only not explain anything — it teleports us back to the age of mythology. The simulation hypothesis annoys me because it intrudes on the terrain of physicists. It’s a bold claim about the laws of nature that however doesn’t pay any attention to what we know about the laws of nature.”
Hossenfelder believes that there is a trivial way in which to say that the simulation argument is correct:
“You could just interpret the presently accepted theories to mean that our universe computes the laws of nature. Then it’s tautologically true that we live in a computer simulation. It’s also a meaningless statement.”
Leaving the realm of linguistic logic and entering into the mathematics and fundamentals of physics, Hossenfelder goes on to explain that a universe cannot be built with classical bits and still have quantum effects. You also need to take into account special relativity, which no one who has been testing any kind of experimental hypothesis has been able to remedy.
Indeed, there are good reasons to believe it’s not possible. The idea that our universe is discretized clashes with observations because it runs into conflict with special relativity. The effects of violating the symmetries of special relativity aren’t necessarily small and have been looked for — and nothing’s been found.
No ability to distinguish a simulated universe
Lisa Randall, a theoretical physicist at Harvard University, is somewhat baffled as to why this is a topic up for serious debate. Her logic is operating under the premise that this idea cannot ever be tested scientifically and is just mere linguistic floundering for scientists.
“I actually am very interested in why so many people think it’s an interesting question,” she has said about the topic.
Her prediction is that the chances of this argument turning out to be right are effectively zero. There is zero evidence that can be conceived of that we’re living in a simulation and runs in parallel to the old idea that “a god did it.” Now the only difference is that a computational system has taken the place of the clockmaker, Jehovah, or the world being the breath of Brahmin and so on in this similar strain of religious examples.
To really distinguish a simulation, you really do have to see just our whole notion of the laws of physics breaking down, or some of the fundamental underlying properties… Not because of interaction of the environment, but just the computer just couldn’t keep track of stuff… I mean, to simulate the universe, you need the computational power of the universe.
Inherent contradiction in the argument
Cosmologist Sean M. Carroll believes that there is a blaring contradiction endemic to the argument. He first lays out the gist of the argument in a supposed logical system. Here is how he views the simulation hypothesis:
- We can easily imagine creating many simulated civilizations.
- Things that are that easy to imagine are likely to happen, at least somewhere in the universe.
- Therefore, there are probably many civilizations being simulated within the lifetime of our universe. Enough that there are many more simulated people than people like us.
- Likewise, it is easy to imagine that our universe is just one of a large number of universes being simulated by a higher civilization.
- Given a meta-universe with many observers (perhaps of some specified type), we should assume we are typical within the set of all such observers.
- A typical observer is likely to be in one of the simulations (at some level), rather than a member of the top-level civilization.
- Therefore, we probably live in a simulation.
With the above logic in mind, Carroll goes on to explain that if we accept all of that then we most likely live in the lowest level of the simulation, in which we wouldn’t be able to perform any of our own simulations even if we wanted to and somehow had the capability to do so.
Hopefully the conundrum is clear. The argument started with the premise that it wasn’t that hard to imagine simulating a civilization — but the conclusion is that we shouldn’t be able to do that at all. This is a contradiction, therefore one of the premises must be false.