The simulation argument has its background in the philosophical question of reality and reality perception (in a field of study formally known as Epistemology or Theory of Knowledge). The doubt in the true nature of what we perceive as reality has been expressed by philosophers as early as Plato (“Allegory of the Cave”) and led to the foundation of rationalism under René Descartes (“Cogito ergo sum”); it even found it’s modern day interpretation in pop-culture movies like “The Matrix”.
Until very recently, the thought that our universe might be simulated was considered science-fiction-y at best or right out lunatic at worst. I mean like tin-foil-hat lunatic. However, recent technological advances in neuroscience, physics and computer science shook the very foundations of what we thought impossible, or deemed too far-fetched to ever take seriously.
Now we have a bunch of very smart people taking the “simulation argument “ seriously and trying to investigate it with the tools of science and rational thought.
Of scientific paradoxa and probabilistic reasoning
To understand the scientific basis for the simulation argument, we have to go back in time and start with Nobel-Price winning nuclear physicist Enrico Fermi, infamously known to the world as “architect of the atomic bomb” together with J. R. Oppenheimer, one of his many contributions to the fields of physics. While working at Los Alamos, Fermi went into an argument about the recent spate of UFO reports in the 60’s, which famously led him to proclaim “Where are they?”. The interesting part about Fermi is not his curiosity, but that he had the intellectual courage to followed up with some probability calculations. His reasoning was simple, he calculated that with the large number of stars in our galaxy (the Milkyway) alone, even if life only occurs on a minuscule percent of all the planets inhabitable, our universe should be filled with simple life. Furthermore, if life has a tendency to overcome scarcity similar to what we observe on our planet (evolution), then intelligent life would have developed on a fraction of these planets as well. Now given that life took “only” one billion years to start after the formation of our planet (which is a young planet in our 13,8 billion years old universe), there has been plenty of planets that have been around at least as long, or way longer, than earth, giving potential alien civilizations millions of years time to expand into the universe and colonize it. However, we do not observe any sign, signal or artifact of alien civilisations in our universe; so where the hell is everybody?
There are several potential answers to Fermi’s paradox, and they boil down to three main ideas:
- extraterrestrial life is rare or not existent (“We are alone”)
- No other intelligent species have arisen yet (“We are the first”)
- Intelligent species self-destruct before being able to colonize the galaxy (“The big filter lies before us”)
Explanation one is the most depressing, two seems to be the most improbable, while explanation three is by far the scariest. Either way, there is no hard evidence for any of those explanations.
Related to Fermi’s paradox is the Drake equation, named after and written by Frank Drake to stimulate scientific discussion at S.E.T.I projects. As such, the parameters formulated by the Drake equation are considered guidelines to what we would need to find out to make better estimations, while realistically, we lack capabilities to estimate their true values. (That’s one of the problems we face once confronted with infinity and it’s relation to certainty) In any case:
Most scientist agree that given what we know so far about the vastness of the universe and the history of our planet, it seems very unlikely that earth is unique to host life.
From astro-physics to computer science
Usually computer science does not occupy itself with investigating our universe, but with creating universes on their own. The last decade of progress in creating virtual things has fundamentally shifted how we think about reality. We all use virtual currency to pay for stuff, or store and manipulate data in the cloud every day. While it was unthinkable to ever mistake a computer-generated human face, poem or artwork with a real human a generation ago, the line has gotten very blurry right now.
Virtual reality is gradually losing its sci-fi touch, as we get a better understanding of our neurobiology and constantly increase our computational capabilities. Have you ever experience how real it can feel to be completely immersed into a video game? Take a look at people’s reactions to Oculus Rift Virtual Reality glasses. That is just the beginning.
What we experience today is the exponential progression of information technologies, we have now computers understanding human speech, reading human handwriting, beating us at our own games like Jeopardy and Go.
Well that’s all fine, but what does our technological progress tell us about our universe?
At some point, if technological progress does not unexpectedly stop, our computers will be extremely potent at generating virtual realities, which in turn will be so convincing, so accurate, so fundamentally similar, that it will be impossible for us to distinguish them from reality. While today we are working hard to simulate a couple of hundred neurons up to the human brain, consciousness is still a dubious concept for us.
Any technological advanced civilisation will be able to generate and live within simulated worlds that are inhabited by simulated conscious entities; which will be conscious of themselves by all definitions. How would those entities know that they are living in a computer simulation?
Coming back to Fermi’s paradox and the Drake equation, we know that there is a very high probability that our universe is filled with life, even if we are not sure why we do not detect them.
We have to assume that there exist an abundance of alien civilisations out there, many of them computationally more advanced than we are. Furthermore, there is no reason to believe that they would not be able to run computer simulations of immense power and size.
They might choose not to do so, but they will at least have the computational capabilities to make crazy realistic simulations. Furthermore, we have to assume that each advanced civilisation could potentionaly run countless numbers of simulations, similar to how many games we are creating, thus we face a high amount of simulated universes compared to “real” universes.
The purposes of these simulations could be manifold, maybe it is to estimate physical parameters that lead to life, a big experiment to understand how physicals laws have to fall to allow intelligence to develop. Maybe it’s as simple to simulate universes for them as is growing a bacteria civilisation in a petri-dish for us, or they just create them for fun like we do with our videogames. In any case, if we are so humble to believe that we are neither the first nor the only intelligent life in the universe, we have to face the following conclusion:
Given the sheer amount of simulated universes compared to civilisations simulating them, the overwhelming odds are that we will be part of a simulated universe.
To put this in perspective: If one civilisation generates 1 million virtual reality universes with conscious species inside, then only 1 out of 1.000.001 conscious species will be “actually real” and the rest will be simulated, while still believing their world is “real”.
So the real question we have to ask ourselves is not about the odds that we are living in a simulation, but how likely it is that we will be a technological advanced species that can simulate universes with conscious beings inside?
This question leaves us with Field pioneer and Oxford philosopher Nick Bostrom, who has been tackling the logical implications of technological advancements for years. He came to the conclusion that least one of the following propositions has to be true:
(1) the human species is very likely to go extinct before reaching a (technological advanced) “posthuman” stage;
(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);
(3) we are almost certainly living in a computer simulation
There is no way to know which one of the three is true or even more likely, for point one, some people argue that any higher technological civilisation is bound to destroy itself before reaching post-human level, while others question the odds that we will ever be able to simulate consciousness. Some philosophers argue for the high likelyhood of point 2, explaining that as we progress, also our moral progresses, and for future generations it will be unthinkable to create simulations with conscious beings inside, because it would be not ethical. Questionable if all future civilisations and individual actors would subscribe to the same moral standards though, in my opinion. In any case, point 1 and 2 will play out if we give it enough time.
The human species either makes it to post-human civilisation or dies out before, if we live we will agree upon common moral when we reach the capabilities to simulate such universes.
Which brings us to point 3, which not unlike the spaghetti monster, will be impossible to disprove. There is no experiment for “realness” of our universe. Every argument we could ever make, every experiment we could think of, could just be part of the simulation. If everything is simulated, all our actions, thoughts, observations will be part of the simulation to.
However, if we can not disprove it, there still might be a chance to proof the existence of a computer simulation. It is remarkable that our universe runs on natural laws that have their roots in mathematics, which is a purely human construct. Math is the father of things like logic and algorithms, one might call them the “natural laws” for our computer programs. The question is, why would our universe feel like it needed to comply with the laws of math? Furthermore, everyone who codes knows that there are things that can screw up algorithms, things like NP complexity, Alan Turing’s halting problem and it’s mathmatical counterpart of Gödel’s incompleteness theorems. The idea behind this is:
if computer programs are incomplete and can screw up, we can basically look for bugs to proof if our universe is a simulation.
However, it will not be as easy to find a bug like the infamous “Déjà vu”-bug in the Matrix.
One way some physicist think about this problem is on the computational power needed to run a simulation like our universe. It is practically impossible to compute how every particle will move and interact with all other particles, so maybe the simulators cut corners and they are not simulating everything, just approximating their algorithms to work at a certain granularity. Think about what we do in our computer simulation, we have a certain pixel depths that defines the image resolution (=granularity) of our simulation; usually the higher the resolution, the more computational power we need.
One way how we could find proof of being in a simulated universe is to just zoom further into the resolution of our universe and look for pixels.
If we find pixels, for physicist this would be for example a gap in resolution between energy and the mass of the smallest sub-atomic particles, this would be some strong evidence for the simulation argument. However, so far there has always been a smaller particle to find; we found that atoms make up molecules, and that quarks make up atoms. If we would find “zorcs“ making up quarks and “snorks” making up “zorcs” (fictional fun names) and so on, than the probability of a simulation would be lowered with each new layer of particles that a simulator would have to find computational power for. Now it should be clear that having basically an infinite resolution simulation would drive computational demand also to infinity, which makes it impossible to compute.
However, if we find bugs in our universe, or if we manage to advance to a technological advanced civilisation that can create crazy accurate simulations, we would have to give in to a high probability of being simulated ourselves.
So what does it all mean for our life right now?
One intriguing possibility is that our view in science is strengthened, because if our natural laws by which the universe runs are actually hardcoded, then investigating this code will be the best tool we have in predicting the future. Furthermore, we could conceive that our simulation can be shut off at any time (though unlikely, why run a simulation for 13,8 billion years and then shut it of during one species lifespan?), so we better make the best out of our life as long as we still exist (which is a good advice no matter what you believe in anyways).
Finally, we are left with one notion:
Our universe is too beautiful not to be experienced by conscious beings, so simulation or not, we might as well enjoy the ride.
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