There's been a lot of talk in recent years about the idea that our Universe—and all of our human experiences along with it—may be running entirely inside some sort of ultra-advanced computer simulation.

The implications of this idea are simultaneously profound and insignificant. Profound because it challenges our perception of reality and rewrites our thoughts on metaphysics; insignificant because it really changes nothing—our lives remain the same whether we do or don't live in a computer simulation (apart from any psychological turmoil that may result in pondering such a question).

But there's also an implication for how it could all end. What if the computer program upholding our Universe suddenly shuts down? What if, mid-sentence, someone closes the program without first hitting CTRL + S and all of our work is lost forever? We'd be effectively dead. Worse than that: erased, our entire Universe banished to non-existence.

This is what I'm referring to as "Death by CONTROL + ALT + DELETE." And to understand how this crazy idea could possibly make sense, follow along here as I attempt to summit this very challenging conceptual mountain. Here are the topics:

  1. Overview of the Simulated Universe Idea
  2. We're already building Simulated Universes
  3. It's just a matter of Computing Power
  4. We're probably not in The Matrix
  5. What does it all mean?
A couple of keyboard strokes could end the whole Universe
Image Credit: Dan Levesque


Acceptance of the simulated Universe theory begins with how you answer a basic question about metaphysics: is the Universe composed entirely of matter and does it adhere to a set of physical laws?

Reasons for not accepting the fully material and physical nature of the Universe would include: belief in a god that can act upon or alter the Universe at will; belief in some sort of spirit realm (heaven, hell, ghosts, etc.) that influences reality; belief in an indestructible soul (the essence of a person) that lives on after the death of the body; or the idea that there's no such thing as a 'physical' world at all, and that everything that exists is upheld entirely by your subjective conscious experience (this is hardcore idealism).

What if all of the physics of the Universe could be written in computer code?
Image Credit: Markus Spiske

Either of these scenarios would break causality as we understand it, and would render scientific observation of the Universe worthless. For example, there's the god problem—some omniscient agent could one day decide to change the laws of the Universe on a whim. If such an agent so desired, it could decide to break mathematics by making it so that two plus two sometimes equals five instead of four, resulting in our never being sure whether or not our mathematical proofs were logically sound or not. 

This is somewhat similar to the act of causing miracles or changing the outcomes of what would otherwise be causally pre-determined events (like stopping a supernova from exploding); if some being external to our Universe is able to cause changes to our Universe, then causality would be broken and science could never tell us anything valuable.

The point here is that unless the Universe is a closed causal system that cannot be effected by some non-material god-like agent, our physical models won't be accurate.

But our experience is that science seems to work really well. We have theories ti explain the physical world that have proven useful over decades and sometimes centuries. We also have mathematical models of physical phenomena that aren't broken—as we can see directly in the case of Einstein's relativity and the continued success of our communications satellites and GPS systems.

Logic is the process that allows us to infer that A + B = C. Science is a more complicated version of that. We know with a very high certainty that combining x amount of chemical A with y amount of chemical B will produce z amount of compound C; and this observation holds no matter how many times this same process is done. 

We're also getting good at manipulating things at the particle level, having mastered nuclear fusion an made advances in materials engineering at the microscopic level (we're figuring out stuff like quantum computers, carbon nanotubes, molecular 3D printing, etc.). 

The Tarantula Nebula, too, could be running in a computer simulation.
Image Credit: ESA/Hubble

The implication for continually improving technologies is that there's no reason why we won't one day be able to model every particle in the Universe and calculate all of their interactions throughout billions of years of the Universe's existence. Doing so would allow us to simulate the Universe in its entirety, and allow us to watch the Universe unfold for billions of years into the future (and all the way backwards in time) with quite a bit of certainty (depending on how accurate our models were).

This is the sort of thing we may want to do in a computer simulation of our own one day—create a model of a big bang, input all of our theoretical physical models, and watch how the Universe expands and changes over time. If the simulated Universe matches our real Universe, then we know our physical models are accurate and that we have a pretty good understanding of cosmology.

And if such a detailed simulation were to lead to the creation of a simulated civilization just like our own, well, that'd be interesting too—sort of a computer nerd's equivalent to Nietzsche's eternal recurrence: a conceptualization of the notion of infinity in which we're bound to live the same life over and over for eternity (as well as every other possible life and non-life, too). 

This might all mean that we're presently trapped in a series of infinite simulations each running their own simulations, each with their own unique sets of conditions and physical laws that may lead to exotic universe and alternative modes of existence that what we couldn't possibly comprehend. How's that for a multiverse?

2. We're Already Building These Simulations

Physicists already create simulations of our Universe, but in small chunks. By inputting known variables (like mass and volume) and combining them with somewhat understood physical processes (like our models of gravity and galactic winds), scientists have been able to simulate galaxies on the macro level, allowing us to model how galaxies evolve and interact over time. 

A human-made simulation of tens of thousands of galaxies.
Image Credit: Schaye et al.

This is a far less complicated version of simulating individual particles, where we're instead simulating whole galaxies (tens of thousands of them) as single objects with a set of properties—that is, looking at really big objects, but not their individual components. 

While we can't yet run a simulation that takes into account every particle in the Universe, we can simulate the general evolution of tens of thousands of galaxies at once. And there could be as many as two trillion galaxies in the observable Universe alone, so we still have a long ways to go in this particular area.

Meanwhile, particle physicists at CERN have been trying to create reliable models of how the smallest particles in the Universe interact with one another. And it turns out that subatomic particles colliding at extremely high velocities are actually very difficult to accurately model, though increasingly powerful particle accelerators have been gradually helping to unlock the secrets of the most fundamental building blocks of our Universe. 

Whether we're aware of it or not, we are in the process of building this Universe-sized simulation right now, today in 2016. All we're really missing is a gigantic computer with enough memory and processing power (well, a unified theory of physics would help too, but that's another topic altogether) to calculate lots of stuff.

To really put things in perspective: accurate weather modelling depends a lot on computer processing power, and we all know how inaccurate weather forecasts tend to be. If this is any indication, a total simulation of our Universe is a loooong way off.

3. It really is just a matter of Computing Power

For decades, the processing power of computers has been approximately doubling every two years, and this trend shows little signs of quitting (it may be slowing, but definitely not stopping). 

From 1997 to 2000, Intel's ASCI Red supercomputer held the record for processing power: it was capable of 1,338,000,000,000 operations per second (1.338 TFLOPS) and cost $67 million dollars. 

Intel ASCI Red: the fastest supercomputer in the world less than two decades ago.
Image Credit: Intel

When Sony launched their Playstation 4 console in 2013, it was capable of a peak performance of 1,840,000,000,000 operations per second (1.84 TFLOPS), higher than the fastest supercomputer in the world only a decade and a half earlier. The price tag? $400.00. Also, it was way smaller.

It only took 13 years for a video game console to surpass the most advanced supercomputer in the year 2000, and it only cost about 1/200,000th the price per FLOP. If airline ticket prices were to drop by a similar amount, it would cost pennies to fly anywhere in the world.

This progress in processing power is important, because it's going to take some seriously powerful computers in order to simulate an entire Universe worth of particles and all of their interactions for billions of years. 

We know that the observable Universe is finite in size and mass, and we have good reason to believe that his may also be true for the rest of the Universe beyond our event horizon (we can only see light that's younger than the 13.8 billion-year-old Big Bang, and a big part of the Universe is likely to be more than 13.8 billion light years distant, so we'll never see it).

This means that the entire Universe has a finite number of logical operations per second, or per millisecond, or per Planck-second (what we conceptualize to be the smallest possible unit of time in the Universe), or whatever other metric we choose to adopt. 

An ancient supercomputer. No simulated Universe to see here, folks.

With only a finite number of operations occurring in the Universe at any given time, then simulating many billions of years worth of a Universe's existence would only require calculating a finite number of operations (that is, calculating the location and state of every particle at every interval)—though that number would be incomprehensibly huge, and I have no idea what order of magnitude it would even be on. 

But as long as there are a finite number of operations, it is physically possible to simulate all of them. It's just a matter of waiting for the hardware to catch up. And in 2016, the fastest supercomputer in the world is about 100,000 times faster than Intel's ASCI Red was, which held that same record just 16 years previously. 

It could take decades, centuries, millennia, or even longer for a powerful enough supercomputer to emerge that can simulate a Universe like our own. But as long as civilization doesn't end and technological innovation doesn't completely stall, it's inevitable that it will one day be possible.

And when that day comes, we will literally have built ourselves an entire Universe in a box—something even Morpheus could be proud of.

4. But No, We're Probably Not in the Matrix

Keanu wakes up and realizes his whole career was a lie.
Should've taken the blue pill.

Image Credit: The Matrix (1999)

We could be, but it seems unlikely that there would be robots growing human bodies for use as batteries. It'd probably be a lot better to just manipulate the weather and use solar power, I would think. Plot holes...

It's far more probable that our thoughts, experiences, memories, and desires are all just 1's and 0's—part of the program. We don't need a physical body detached from the simulated Universe in order to exist inside of it. It's probably a lot easier to just simulate our entire consciousness inside of the computer simulation itself.

Sort of like The Sims. A video game that features simulated people, each with their own behavior patterns, personality traits, hobbies, jobs, and so on. When the original The SIms game launched back in 2000, it was somewhat rudimentary—the simulated people were able to perform basic tasks automatically, but had a limited number of options available to them and depended largely on player control to complete simple tasks, such as staying alive.

The original The Sims was even more boring than real life.
Image Credit: Electronic Arts

Further iterations of the original game have introduced added complexity and variability in the lives of the simulated people. For example, 2014's The Sims 4 includes a complex "emotions" system where these simulated people move through various emotional states, subject to being either positively or negatively effected by their interactions with objects and people in their surrounding environment. 

Rather than simply moving about the environment performing simple functions (like cooking, sleeping, etc.), the updated version of The Sims has resulted in a world in which the simulated people can be emotionally effected and influenced by their surroundings, for better or worse. 

The Sims 4. These poor people have no idea...
Image Credit: Electronic Arts

As technology and processing power advances and more complex iterations of The Sims continue to be developed, the simulated people in the game will become increasingly similar to real people outside of the game world. Perhaps The Sims 57 will reach a point where gameplay becomes identical to reality, and simulated people live lives just as complicated and profound as their real-life counterparts. 

To get super existential, The Sims 4 also allows its simulated people to play video games—and one of the video games they can play is The Sims from the year 2000. This means that human beings are playing a video game in which simulated people can play a video game that features simulated people. 

A simulation in a simulation...
Image Credit: Electronic Arts

18th Century philosopher George Berkeley is famous for his argument that no material world exists at all, and that all of our perceptions aren't based on anything that's physically real. Instead, he argues, everything that exists is only possible because the infinitely powerful mind of god is imagining everything that we perceive firstincluding our own thoughts and our sense of self. The implication here is that, if god stopped imagining everything, then it would all disappear and cease to exist.

Today in the 21st Century, we can take this idea and repackage it—replace the omniscient mind of god with an incomprehensibly powerful computer simulation, one with trillions of lines of computer code being spontaneously generated and altered in order to account for the gradual evolution of the Universe. And voilà, a Universe in a box, no god required.

And now we've reached the summit of the conceptual mountain of despair. Human beings have thought similar thoughts before, they've just been renovated here for 21st Century consumption.

At least this way, instead of floods and plagues, we'll only have to experience brief glitches in computer code—and maybe occasionally a few odd commands from a disgruntled 12-year-old that we feel strangely compelled to carry out, lest we be forced to swim for eternity in a swimming pool we can't get out of.

5. The View From The Top

Even if we are living in a computer simulation, nothing changes. The world doesn't suddenly fall apart. Unless it does...

How secure is our supercomputer/universe? Imagine someone just walks up to the computer that we're all running on and hits CONTROL + ALT + DELETE. The task manager pops up, this psychopath selects "End Task," and we all go night-night forever. 

We wouldn't even know that it was happening. I don't know if that's more or less sad. We probably just wouldn't be consciously aware of the shutdown at all. 

I mean, does a simulated person in The Sims know when the game has been paused? Do they wonder when the player is coming back? When you save and hit exit, do they all scream in terror? Probably not.

When you close your eyes, do you only see this too?

If the Universe follows a sequence of logical operations, one after the other, then hitting PAUSE on that sequence would stop it immediately. But because no other sequences are taking place, there would be no process by which we could ponder the pause event. We'd be frozen in time, unaware that we're frozen. Stopped mid-thought, a thought that could last for eternity without ever being completed. And we wouldn't be consciously aware of it.

All that we would be aware of in this simulation is the logical process of the 1's and 0's playing out in sequence, and to us that would (or does?) look like reality. Our lives would just be contained there, in that big box (if this super-advanced supercomputer is even contained in a 'box' at all). Every second of our existence could take a century for this computer program to compute, but to us, it still only takes a second. 

We would be prisoners here, in this simulated box. Or what is conceptually similar to a box, as we know it. Maybe we're only in The Sims 4 version, and our thoughts are still incredibly infantile compared to those of the programmers of our simulation. Or we could be in that hypothetical The Sims 57 version in which our creators look, talk, think, and behave just like we do. 

If they do decide to delete us, or if the computer we're all running on somehow blows up, or if someone CONTROL + ALT + DELETE's us, then we wouldn't even know it. We'd just be uninstalled, like the previous three versions of The Sims, replaced by the newer, updated version of the software. 

So, if some big floating notification pops up in the sky one day telling us that 'the computer' needs to be 'restarted' to 'install updates' for 'Windows 57' (or some other iteration), let's not panic. Just know that everything will probably be fine, we'll come back to life soon, and then everyone will wish they could just go back to the previous version because it somehow seemed better. Life goes on.

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