Are You Living in a Computer Simulation?

Films like The Matrix and The Thirteenth Floor popularized the notion of a simulated reality, populated by simulated people who didn’t know they were living in a simulation. This might seem like clever idea, but in fact it’s not at all new. The Thirteenth Floor is based on Daniel F. Galouye’s 1964 novel, Simulacron-3, while in 1942, Robert Heinlein wrote “The Unpleasant Profession of Jonathan Hoag”, a short story with similar concepts. Indeed, one could argue that Plato’s myth of the cave is the progenitor of the notion that our world is a mental construct.

So, how about it? Are you living in a simulation? We’re going to look at this question from three perspectives: technology, philosophy, and neuroscience. Each gives us surprising answers.

Technology

In order for the question in the title to make sense, two things about our future state of technology must be true.

1. We will eventually be able to produce simulated people, i.e., self-aware artificial intelligences with the ability to process information in a way that’s indistinguishable from human intelligences; and
2. We will be able to produce a simulated reality of sensory inputs for these simulated people, and do so in such a way that the simulated people would be unable to determine that they were in a simulation.

Despite all the current hype around AI, we are nowhere close to achieving either of these things. Still, the general consensus is that it is possible, some think it’s even likely, that someday, maybe as soon as in the next hundred years, we will achieve the above two things. But the consensus is clear that we won’t do so any time soon.

In fact, we don’t even have a good definition of what it means to be self-aware, what consciousness is, or our how it arises in our brains. We’re a long way from even a theory of how to do (A) and (B).

Besides these theoretical constraints, our hardware is also far from being capable of (A) and (B).

Just for comparison, our brains are capable processing between 10¹⁴ and 10¹⁶ operations per second. Our current fastest super computer processes roughly 10¹⁸ operations per second, so that computer could—in theory—simulate as many 10⁴ or as few as 10² human brains. But, that doesn’t take into account simulating the reality for these brains, which could use up another 10⁸ (or so) operations per second. In other words, our fastest supercomputers couldn’t even do a simulation involving a few dozen simulated people and their associated reality, assuming we even knew how to simulate people or reality in the ways (A) and (B) posit.

Philosophy

We already mentioned the myth of the cave, but there’s a 2003 paper by the philosopher Nick Bostrom that asks the specific and personal question that’s the title of this newsletter: are you living in a computer simulation? Bostrom’s contribution is that he reframes this question: What are the chances you are living in a computer simulation? Instead of “yes” or “no,” this reframing lets him assign the odds of this being true. Are they one in one hundred? One in a thousand? Even? His reframing gave the following astonishing conclusion.

In terms of our question, Bostrom concluded there are two possibilities.

1. We someday acquire the abilities in (A) and (B) above, in which case it is almost certain you are living in a simulation—the odds are trillions to one that this is true; OR
2.  We never acquire the abilities in (A) and (B) above, so we’re never able to create the necessary simulation, so the odds are zero.

If, in fact, (A) and (B) are feasible, then if we’re not living in a simulation conclusion (2) suggests we destroy ourselves before our technology advances to the point that we can create such simulations.

One could argue that if we ever achieve (A) and (B), many simulations will include past realities, as in The Thirteenth Floor. That means that if we ever achieve (A) and (B), the future reality in which we do so will generate simulations that exactly mimic the world we think we live in.

In passing, I should note that Bostrom’s reasoning in getting to (1) and (2) is open to argument. For example, if (B) includes simulating features like quantum mechanics and the uncertainty principle, it’s not at all clear that we could ever achieve (B) on the scale required to reach his conclusions (1) and (2).

Neuroscience

Neuroscience tells us that most of what we think we see is a visual construct inside our brains, so we’re already living in a simulation, just not one that’s computer-generated.

Try this. Close your left eye. What’s that big thing jutting into the left side of your visual field? Oh. Of course. It’s your nose. Open your left eye, and it magically disappears. That’s evidence of your brain correcting what you “see” by consolidating the visual information from the two eyes and editing out the unnecessary bits. It’s not that your nose isn’t necessary. It’s just that we don’t need to see it in order to avoid that saber tooth tiger lurking in the savanna.

Next, hold out your arm and give yourself a “thumbs up.” See your thumbnail? That’s roughly one degree of visual arc. It turns out, that’s how much of the world we can see with 20/20 vision. The rest is blurred—so much so, that we’re legally blind outside of that one degree arc. It doesn’t look that way, because your eye is subconsciously moving around all the time, scanning your environment. The brain patches these scans together, seeking out patterns and predicting what’s in the out-of-focus pieces. Under most circumstances, the brain does a good job of this. Fooling that prediction is the source of most optical illusions.

Then there’s that famous dress. You remember that one, right? Is it blue and black or is it white and gold? The dress revealed individual differences in color perception.

The brain has over 100 trillion neural connections. That’s more connections than there are stars in the Milky Way. Those connections somehow work together to create us and the world we think we live in. It’s still a mystery how this gives birth to the self-aware, free-willed individuals we all consider ourselves to be. It’s even possible that our perception of self is an illusory construct of this complex neural network.

The point here is that neuroscience seems to be telling us that we already live in a simulated reality, one created by our brains based on our sensory inputs. Also, in case you didn’t know, that input includes information from between fourteen and twenty senses or even more, not just five.

Conclusion

So, what’s the answer? Are you living in a computer simulation?

The consensus is that it’s possible we might build such a simulation someday. Bostrom’s analysis says if we ever do, then the answer is an emphatic yes. But neuroscience says we’re already living in a simulation.

If the real world we think we live in is an illusion constructed by our brains, does it matter if we’re living in a computer simulation? Would your choices be any different if it turned out you are living in a computer simulation? If so, what choices and why would they be different? How about other people? Are they NPCs, non-player characters in the game of life and thus expendable? Or are NPCs, who are exactly the same as real people except for their cybernetic origin, deserving of the same respect and agency as you? What if you’re an NPC? If you were, you wouldn’t know it (see (B) above).

As authors and artists, these are kinds of questions that are interesting. They are questions about the meaning and purpose of life, about what makes us human, about ethics and morality, about freedom and destiny. Whether reality is just shadows on the wall of Plato’s cave or a simulation in Neo’s matrix, whether it includes the uncertainty principle or is deterministic, we still have to answer these kinds of questions.

In thinking about fiction and reality, I always come back to something Hemingway said: “I tried to make a real old man, a real boy, a real sea, a real fish, and real sharks. But if I made them good and true enough, they would mean many things. The hardest thing is to make something really true and sometimes truer than true.”

Whether reality is simulated or not, there’s still the shared truth, the truth that Hemingway is talking about, the truth that makes us all human.

That’s what matters.