It could well be called the mother of all conspiracy theories, the most audacious of all pseudo-scientific ideas, or the most useless of all Byzantine discussions. But prestigious philosophers, reputed physicists and millionaire technologists are considering the possibility that we and our world might not be real, but only part of a kind of video game, an enormously sophisticated simulation: the Second Life or The Sims of the future.
The idea has often been dealt with by science fiction. One of the most popular examples is the film saga of the Wachowski brothers—The Matrix—in which intelligent machines keep humans immersed in a simulation of reality. But for centuries, the question of whether reality is really as we experience it has captivated philosophers. Already in the 4th century BC the Chinese skeptical thinker Zhuang Zhou dreamed that he was a butterfly, and when he woke up he could not help wondering: “I did not know whether it had formerly been Zhou dreaming that he was a butterfly, or it was now a butterfly dreaming that it was Zhou.”
In its modern form, the simulation hypothesis is usually attributed to the Swedish philosopher at Oxford University (UK) Nick Bostrom, author of a 2003 work that has generated endless debate. Under the title “Are you living in a computer simulation?” Bostrom stated in the Philosophical Quarterly journal that at least one of the following propositions is true: either humans will extinguish themselves before they reach a “posthuman” stage, or the posthuman civilization will not be interested in constructing simulations of their ancestors, or we live in a computer simulation.
Humanity will be posthuman
Bostrom argues that the evolution of humanity will lead to a posthuman state in which our descendants will have immense technological power, enough to create complex simulations of their ancestors in which everything seems real, even the consciousness of the characters. Posthumans will have such easy access to these simulations that they will be able to build as many as they wish, far exceeding the number of actual ancestors. Therefore, given that the probability of any of us being a simulated character is much greater than that of being a real ancestor, it can be concluded that we almost certainly live in a simulation.
Unless, Bostrom continues, such simulations do not come into being. But this would only be possible in one of two cases: either humanity is annihilated before reaching the posthuman state, or for some reason our descendants decide not to simulate their ancestors. Assuming that human beings endure and assuming our natural technological evolution, the conclusion is that most probably we, and our entire world, are as real as any of today’s videogames.
Bostrom’s proposal elicited responses of all kinds, from those who dismiss it for being unscientific or a purely mental game without much interest, to those who have supported and extended it with new works. The Swedish philosopher collects the progress of the discussion on a website that develops the so-called “simulation argument.” Some critics allege that it will never be possible to make such perfect simulations, with characters that do not know what they are, or that it is obvious to us that we are human, or that the possible future simulations have not yet been created and therefore we are real, or that if the simulations were able to create simulations of themselves they would eventually cause the computers of the posthumans to crash.
Glitches in The Matrix
But how are we able to know the truth? In The Matrix there were glitches such as déjà vu that offered glimpses of the true nature of the simulation. Interestingly, the idea has almost become a popular meme on sites such as Reddit, where users share unexplained events that have happened to them and that they interpret as glitches in the Matrix: a second life lived in a dream, or a box that changes its contents the second time it is opened moments later.
However, Bostrom does not endorse the glitch argument: whether we are real or not, we will always hear such stories, which are probably due to the twists and turns of the human mind even within a simulation. Posthumans, Bostrom argues, “would also have the ability to prevent these simulated creatures from noticing anomalies in the simulation.” The philosopher raises a disturbing argument: “even our own humble brains—unaided by technology—usually manage to prevent us from realizing when we are dreaming at night, even though the typical dream is teeming with the most fantastic anomalies.”
The logical argument leads to the inability to prove that we are real, because “any evidence we could ever get could be simulated,” said philosopher David Chalmers last year at the annual Isaac Asimov Memorial Debate at the US Museum of Natural History, dedicated in 2016 to the simulation hypothesis. Therefore, if we are not a simulation, we will never know for sure.
“You are living in a computer simulation”
But the opposite would be possible: to demonstrate that we are in a simulation. Bostrom writes on his website: “For example, the simulators could make a window pop up in front of you with the text: YOU ARE LIVING IN A COMPUTER SIMULATION. CLICK HERE FOR MORE INFORMATION.” But in the absence of this help, some physicists think that the detection of certain unnatural anomalies, such as an asymmetry in the cosmic rays, could reveal to us that the universe is a montage. The idea is that if the computational power of the posthumans were limited, their simulation would be bound to certain simplifications that would break the space-time continuum into discrete points.
We could also hack the source code. Some scientists and philosophers have been arguing for years about the so-called “fine tuning of the universe,” how certain fundamental physical constants seem to have the proper values for the cosmos to exist, and us with it. As cosmologist Max Tegmark put it, “if I were a character in a computer game, I would also eventually discover that the rules seemed completely rigid and mathematical.”
Scientists needed to break us out of the simulation
But it seems that someone has set out to rid us of doubt. Last October, a report in The New Yorker magazine signed by Tad Friend about Silicon Valley entrepreneur Sam Altman revealed that, “two tech billionaires have gone so far as to secretly engage scientists to work on breaking us out of the simulation.” Friend did not specify who it is, but some technological tycoons have not obscured their obsession with the matter.
One example is Elon Musk. The founder of Paypal, SpaceX and Tesla Motors said last year that the subject of simulation had become so recurrent in his conversations that he had agreed with his brother not to mention it when they relaxed in a hot tub. Musk thinks that there is only one possibility among the billions that we are living in the “base reality.”
Maybe the scientists, hired by Musk or others, will surprise us someday. But the answer might be less grand than we would expect. According to Chalmers, our creator could be “just some teenage hacker in the next universe up whose mom is calling him for dinner.” Let’s hope he does not turn off the computer.