“The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to be.”—Douglas Adams
In 2003 the philosopher Nick Bostrom published a paper called “Are We Living in a Computer Simulation?”, in which he uses solid logic to reach a wacky conclusion. Bostrom argues that a highly sophisticated civilization might choose to run simulations of its evolutionary history, so detailed as to capture conscious experience. If this happens, the number of simulated worlds could vastly outnumber the single, original reality. Therefore, unless such simulations are impossible, there’s a reasonable chance that we live in one.
For the moment, Bostrom’s simulation argument remains pure philosophy. It has not been tested (scientists and philosophers argue about whether it even can be tested), so we should be skeptical about its assumptions and curious conclusion. We don’t yet know if we can make lifelike simulations, nor if they can give rise to consciousness. History is full of smart people who have wasted time pursuing logic down dead ends, unaided by the guiding light of evidence (for example, see Isaac Newton and Kurt Gödel). Where we lack evidence, we lack solid ground from which to make radical claims about reality. Accordingly, when wondering whether we live in a simulation, best to remain agnostic.
That said, some aspects of reality appear to lend support to the simulation argument. Although high-level maths, physics, and computer science will be needed to gather definitive evidence, I believe that potential evidence of our simulated reality is accessible to the average layperson. In the rest of this essay I will present that evidence. I do so not because I think that the simulation argument is necessarily true, but because contemplation of it highlights the limits of our knowledge while reinforcing the strangeness of reality. Intellectual humility and a sense of wonder are vital parts of a full life, and thinking about the simulation argument can nourish both.
Mind, Matter & Experience
Pop culture has helped make the idea of simulated worlds more palatable. Shows such as Black Mirror and movies like The Matrix have familiarized people with the notion that computers could house entire universes. However, while people enjoy fantasizing about simulated worlds, few take seriously the possibility that our own world is a simulation. When presented with the simulation argument, most people write it off by pointing to the limits of technology or the apparent miracle of consciousness. How, they ask, could information technology possibly give rise to consciousness or a world as complex as ours? Sure, video games might look realistic, but ultimately they’re just lines of code and pixels on a screen.
And the doubters might be right: information technology may never be up to the task of producing consciousness within other worlds. But the very existence of brains and minds seems to suggest otherwise.
To the best of our knowledge, every iota of experience is the product of brains and nervous systems. Sights, sounds, smells, and sensations all emerge from the arrangement of our neural architecture. And this architecture has much in common with information technology. Neurons can be either firing or at rest, just as binary can read either “0” or “1”. Brains transmit signals through electricity, just as computers do. To build neural implants or other brain–computer interfaces, we draw upon knowledge of information processing, and the resulting success implies that brains do, quite literally, process information. In this sense, the brain is nature’s own information technology.
It’s therefore plausible that felt experience is an emergent property of some branches of information technology. As the physicist Max Tegmark said in Our Mathematical Universe, perhaps consciousness is simply what it feels like to process information.[1] And if biological systems produce consciousness by processing information, why couldn’t artificial systems do the same?
But even if we could create experience through information technology, wouldn’t new consciousnesses simply exist within our original, base reality? Brains might prove that we can simulate minds, but do they also prove that we could simulate worlds? Maybe. After all, we weave intricate worlds out of whole cloth every night when we dream. And if we involuntarily dream up self-contained worlds, who’s to say that we couldn’t voluntarily create them?
Though the idea of fully-fledged simulated universes might seem improbable, we must remember that we’re not even a century into the modern computing era. In the 1950’s we had punch cards; now we’re working on quantum computing. Given another hundred—or thousand—years, who knows what’s possible? As Bostrom writes, “It is currently hard to be confident in any upper bound on the computing power that may be available to posthuman civilizations.”
Light & Information
Our universe has a speed limit. Nothing can travel faster than the speed of light, which is around 300 000 kilometres per second. No matter how much energy you put into a system, you cannot break this barrier. At first glance, the cosmic speed limit seems strangely arbitrary: why should it exist, and why does it equal the speed of light? If something accelerates, shouldn’t it be able to do so indefinitely? Stepping back and considering the issue in light of the simulation argument, though, perhaps we can make sense of it. Maybe the cosmic speed limit is a consequence of the fact that we live in a simulated world.
Any world made of information would be constrained by the speed at which information can be transferred and processed. Regardless of complexity or content, simulations are ultimately limited by the speed of information transfer (to believe otherwise is like believing that a car could travel faster than its tires). And upon reflection, information and light have much in common.
Light has no mass and reaches lightspeed instantaneously. Photons need not accelerate, because from the moment of creation they’re already moving at the speed of light. These are puzzling properties—how can something have no mass and no acceleration, yet move through the world at the cosmic speed limit? Does anything else exhibit such traits? In fact, yes: pure information is a massless, ethereal property that can reach across vast distances at the speed of light. And since information is not physical, it—like light—undergoes no acceleration.
Given these similarities, one could suppose that the cosmic speed limit is actually the information speed limit. If our world is a simulation, then an upper speed limit—equal to the speed of information—is just what we’d expect.
Fungibility & E=mc2
On the surface, our world appears incredibly diverse. Unique elements in specific arrangements give rise to distinct forms, each with their own characteristics. Yet there is a unity to reality that we often overlook. Upon close inspection, the differences throughout nature collapse into a kind of sameness. For instance, every element in the periodic table is built from the same array of smaller particles (called composite particles), which themselves are composed from the same set of even smaller particles (called elementary particles).[2]
This is nothing new; we’re all taught about protons and electrons in science class. But we rarely appreciate the extent to which elementary particles (the base constituents of matter) are actually the same. When considering two photons, we tend to think that they appear identical, which misses the point that they are identical. This counterintuitive property, known as fungibility, can be understood by thinking about electronic money.
In The Beginning of Infinity, the physicist David Deutsch writes about how, when moving a dollar around in an online bank account, it makes no sense to say whether the dollar that’s been moved was the last dollar deposited or some other dollar. All of the dollars in an (electronic) account are fungible, meaning that they are “literally identical in every way except that there are [more than one] of them.”[3] Just as electronic money is fungible, so are many basic components of reality.
Fungibility is a tough concept to grapple with. It makes sense when thinking about something as simple as a bank transfer, but how could material aspects of reality be fungible? How can physical things be the same yet not-the-same all at once? If we suspend our disbelief and imagine that we live in a simulation, fungibility makes more sense.
In a universe made of information, we’d expect to see fungibility everywhere, because information is a fungible property. For example, the following numbers are fungible: 19, 19, 19. But why? It’s not because the pixels are identical, nor because they occupy the same region in space (they clearly don’t). These numbers are fungible because the information conveyed by them is identical. In information-technology, fungibility abounds: strips of code can be identical—thus interchangeable—yet occupy different regions in the overall structure. If reality is made of information, fungibility should come as no surprise. For instance, if a class of fundamental particles all run on the same code, they can’t be anything but fungible.
Taking things a step further, the unity revealed by modern science could flow from the fact that reality, at a fundamental level, is pure information. Though matter and energy appear irreconcilably different, mass-energy equivalence (captured in Einstein’s famous E=mc2) tells us that mass and energy are actually aspects of the same underlying property. By peering deeply at reality, we might be converging upon the common, fungible bits of information that structure our world.[4]
Quantum Weirdness
Bostrom has proposed that simulations could save on processing power by only rendering that which is experienced. Just as video games need not render everything at once, so a simulation could render its world on the fly, constructing it only where conscious experience occurs. Remote astronomical objects and nearby microscopic objects could be coarse-grained when out of sight. For instance, a few photons from a distant star would suffice as a placeholder for that star, so long as we aren’t looking closely. As Bostrom writes, “On the surface of the Earth, macroscopic objects in inhabited areas may need to be continuously simulated, but microscopic phenomena could likely be filled in ad hoc.” In other words, in a simulated reality the observed and unobserved worlds might be starkly different. Unless an observation takes place, simulated phenomena could exist in a radically conserved form.
In our own world, there’s been much speculation about strange happenings at the quantum realm, where our ability to measure physical properties is fundamentally limited. Perhaps this is yet another consequence of living in a simulation.
The uncertainty principle—not to be confused with the observer effect, which holds that measurements affect a system—states that our ability to assess the physical properties of particles is fundamentally limited. For example, we cannot know both the position and momentum of particles at the quantum realm; the better we know one, the worse we know the other. The uncertainty principle is only significant when considering microscopic objects; it has little to say about macroscopic ones.
In a simulation designed to conserve processing power, we could expect to find something like the uncertainty principle. If, to save on computing power, quantum reality regularly goes unrendered, maybe our universe cannot actually render the full quantum realm. When we peer at the smallest building blocks of matter and energy, our knowledge may ultimately be bound by the limits of our simulation’s processing power.
If video game characters could analyze the nature of their reality, they’d eventually hit upon a world that appears incomplete and inconsistent. Given the proper maths and physics, they could make some sense of it, but compared to familiar existence it would be thoroughly baffling. We may be more similar to such video game characters than we care to admit.
Improbable Events
I’m a skeptical person. I don’t believe in reincarnation, extrasensory perception, telepathy, or telekinesis. Where reports of such phenomena surface, I assume that trickery, credulity, or outright lying is the cause. That said, there is much we don’t know, and many smart people claim to have found evidence for these outlandish ideas. The astronomer Carl Sagan, though he didn’t subscribe to parapsychology, thought that such phenomena were worth investigating. As he writes in The Demon Haunted World:
[…] there are three claims in the ESP field which, in my opinion, deserve serious study: (1) that by thought alone humans can (barely) affect random number generators in computers; (2) that people under mild sensory deprivation can receive thoughts or images ‘projected’ at them; and (3) that young children sometimes report the details of a previous life, which upon checking turn out to be accurate and which they could not have known about in any other way than reincarnation.
Regarding reincarnation, Sagan is likely alluding to the work of Ian Stevenson, a psychiatrist who spent decades investigating thousands of children who claimed to remember past lives. While it’s tempting to write off Stevenson’s work as a product of gullible confirmation-bias, many respected publications—including the Journal of the American Medical Association—have described his research as methodical and unbiased.
Although I suspect that Dr. Stevenson’s work was indeed a casualty of wishful thinking, nobody can say for sure. Given the pittance of rigorous research on reincarnation and our rudimentary understanding of the mind, we must be willing to tolerate ambiguity for some time yet. If, somehow, reincarnation or other ESP-like phenomena turned out to be real, we’d have to figure out how to incorporate them into a scientific worldview.
Many people claim that the existence of supernatural phenomena would undermine the power of science. But if supernatural phenomena truly exist then they are, by definition, natural phenomena, wholly subject to the explanatory tools of science. Therefore, if reincarnation, telepathy, or any other fantastic notion were true, they would be true for reasons that could, in principle, be explained. If parapsychic phenomena ever prove real yet elude scientific explanation, I’d suggest that we should ask whether the simulation argument can help explain them.
In any elaborate simulation, errors would crop up now and again. Many of these would go unnoticed, masked by statistical noise. But wherever underlying code is complex and underlying calculations demanding, we could expect more pronounced errors. Brains, being so intricate, would be especially finicky aspects of any simulation. Therefore, we might expect to see some strange happenings when it comes to brains, which could shine through as parapsychic events.
Consider a hypothetical reincarnation. In a simulation, it’s unlikely that new brains would be coded from scratch. To conserve computing power, they could be based on templates, which would update every generation to preserve evolutionary changes. A single brain might be a patchwork of code from several stored templates. If the simulation ever drew from the wrong template (or from the wrong segment of the proper template), the resulting brain could contain memories or personality traits that don’t belong. Denizens within the simulation might interpret this as divine reincarnation, never realizing that it’s actually the profane result of a data-retrieval error and some misplaced code.
Again, I doubt that reincarnation or similar phenomena exist. But if they do, we should ask whether it’s time to take the red pill and give the simulation argument serious thought.
* * *
We can speculate endlessly about what it would mean to live in a simulation. Could it explain why mathematics and logic are capable of describing our world? Or why the laws of physics seem so fine-tuned? Or why matter appears to lack form and substance when viewed up close?
It’s strange to look around and imagine that everything is the product of information processing. But is such a thought any stranger than the fact that solid objects are mostly empty space, or that massive bodies curve space-time, or that something—rather than nothing—exists?
Wherever our speculations lead, they do not change the fact that this reality, here and now, is the only reality we’ve got. If anything, contemplating the strange nature of existence should highlight this fact. We may never know whether we live in a simulation or not, and in the end it probably doesn’t matter. But pondering the unknown does matter, as it can liberate us from the familiar self-concern of conventional existence. In this way, the simulation argument is worthy of speculation.
[1]Although Tegmark believes that we live in a mathematical construct (and a multiverse), he does not believe that we live in a simulation.
[2]Protons and neutrons are examples of composite particles; photons, neutrinos, and quarks are examples of elementary particles.
[3]Deutsch believes that we live in a multiverse but not that we live in a simulation. In fact, he recently published a paper arguing that information emerges from the laws of physics, not vice versa.
[4]A bit is the simplest unit of information. The answer to a “yes or no” question or a binary signal each provide one bit of information.
Stories From the Ground. 