Do We Live in a Simulation?
Before long, humans will simulate a worm brain. Then a mouse brain. Following that, a monkey brain. And after the monkey comes the brain of an eccentric billionaire living in a fortress beneath Silicon Valley.
The wheels may be in motion, but the task won’t be easy. The brain of even the simplest creature, in fact, is extraordinarily complex. For instance, the nervous system of Caenorhabditis Elegans – the roundworm we have yet to emulate – has only 302 neurons. But how these neurons interact to produce various behaviors has to date eluded our understanding. The worm, it seems, isn’t as dull as it looks.
By contrast, the human brain has around 100 billion neurons and perhaps a million billion synaptic connections between them. Our standard wetware is the most intricate structure in the known Universe. Even so, barring a global cataclysm that hurtles us back into the Stone Age, researchers should one day achieve whole brain emulation. To accept this premise, we need only assume that our evolved brains aren’t the only doorway to human-level intelligence. Physical processes can be replicated.
Once our knowledge of neural architecture nears completion, we could copy every aspect of mental life onto computer circuitry. Our minds could be reduced to strings of clever code. This code could then be inserted into a simulated environment, programmed with gravity, blue skies, and any other factor to make us feel at home. It seems obvious that a few hands would be raised to test this technology. The prospect of digital life-extension would be too tantalizing to resist.
Imagine you volunteer to be the first person copied to the cloud. You will be testing version 1 – a crude simulation of consciousness. In V1, you will appear to reside in a small country home with one computer for communication purposes. The entire experience, of course, will actually be housed within a powerful server back in the real world.
The experiment is a success. The first communication between simulation and reality – a few words of text on a monitor - is chronicled in headlines across the globe. But soon you grow disaffected with your artificial abode. It’s too simple. Too boring. After all, you’re hanging out on a mere acre of ersatz turf with no HBO access.
You long for the nuanced comforts of your real home and tell the coders this. And so, fueled by a cocktail of nootropics, they get back to work. Soon they develop a super-intelligent program to simulate worlds. Simply tweak a few criteria and out pops a simulation. To your delight, you are presently transferred to a richer environment with a few others as company.
The overarching goal, however, is not to make you happy, but to build a virtual world indistinguishable from the physical world. To test the "reality" of each simulation, the coders know they can’t simply upload existing minds. These minds would be wise to the game. The rational thing to do, reasons the chief programmer, is to simulate unique human brains to populate the digital matrix. In other words, all inserted subjects will be "blind" to the true nature of their reality.
The experiment begins without any discussion of its moral implications. Millions of universes - each filled with artificial human minds - are churned out. Some scenarios end in spectacular disaster. Other scenarios, more whimsical than scientific, feature God-like behemoths that demand all people wear underwear on the outside. Most simulations, however, hang close to the bounds of the base reality.
One night, the chief programmer wakes in a sweat. She just dreamed she was inside a simulation. It all seemed real - her husband’s smile, her daughter’s laugh, the smell of wet grass. But she knew it wasn’t really real. And that alarmed her.
Waking up from the dream, however, doesn’t soothe her nerves. ‘How do I know,’ she wonders, ‘that I’m not in a simulation now?’
She bounds out of bed and powers on her computer. With deft strokes, she creates a statistical model to analyze the probability of her living in a fake Universe (given the current capacity to create computer worlds.) She gets the answer she feared: the number of potential simulated worlds vastly outnumbers the number of actual worlds. The seasoned programmer knows what this probably means. She gulps a pint of simulated saliva.
It may sound bizarre, but the programmer’s epiphany is not simply the stuff of science fiction. Given a world in which we simulate worlds, the philosopher Nick Bostrom makes a detailed case that we are likely living in a simulation ourselves. If humans: 1) don’t go extinct and 2) decide to simulate our ancestors, asserts Bostrom, then it becomes statistically probable that we’re just one iteration in a digitized multiverse.
“One thing that later generations might do with their super‐powerful computers is run detailed simulations of their forebears or of people like their forebears,” writes Bostrom. “Because their computers would be so powerful, they could run a great many such simulations. Suppose that these simulated people are conscious […] Then it could be the case that the vast majority of minds like ours do not belong to the original race but rather to people simulated by the advanced descendants of an original race.”
Of course, it would be difficult to ever prove or disprove this notion. A simulation, in theory, could be so advanced that our simian brains could never pierce through the veil. And it gets spookier. If we have simulators, it’s also likely that our simulators have simulators. And that means our simulators simulators have simulators too. This quickly approaches absurdity. By this logic, even those residing at the base of reality can never be quite sure of their simulation status.
Before we simulate a human, of course, we’ll have to simulate a roundworm. If we do it right, the artificial worm will act and feel just like a real worm. Scale this up a few orders of magnitude and we’ll have the technology to simulate worlds full of homo sapiens.
And when it becomes clear that we can simulate people, we have to entertain the idea that we’re simulated ourselves. If that’s the case, let’s hope the simulators don’t decide to pull the plug.