You Don’t Exist

It didn’t take Douglas Adams’s faulty mathematics in The Hitchhiker’s Guide to the Galaxy for me to imagine that our universe could be controlled by a naked fat guy eating Cheetos and watching infomercials. It did, however, raise an interest that will have me forever questioning something I once held most true about my existence on this Earth: that it was real. This uncertainty reared its nonexistent little head again while I was researching subatomic particles for a physics class. “Truth is stranger than fiction” seems like something someone might say after a drunken brawl involving his grandmother; at least I would like to imagine that’s how the expression came about. The truth is, as science and physics advance our understanding of this so-called universe, it becomes harder to draw the line between reality and what we believe to be true. I’ve developed a rising suspicion that I, in fact, do not exist. More importantly, neither do you.

Let us start with time. From a young age, we learned the basics: how to read a clock, what the numbers meant, and when to pull the pizza out of the oven before it burns again. Now, as responsible grownups, our eyes are practically glued to our watches. We plan when to wake up, when to show up for work, and how to be fashionably late by starting our assignments the night before they’re due. We take for granted that time is a constant and, neglecting time zones, the same for everyone. Isaac Newton described time as absolute, flowing equally without regard to anything external. For hundreds of years, this was an understanding people generally held to be true.

Then Einstein came along and made things difficult. His theories of relativity showed that the passage of time depends on motion and gravity. To picture the motion part, imagine a poorly constructed monorail full of people hopped up on coffee and Red Bull, traveling at nearly the speed of light. For the passengers, time would seem to pass normally. The spectating crowd awaiting the monorail’s demise, however, would observe the passengers’ clocks running slower than their own. This is time dilation, and experiments with extremely precise clocks have confirmed that it happens. Apparently, being late can be a matter of perspective, although I wouldn’t recommend explaining this to your boss.

Our concept of time has been threatened further by these mischievous physicists. Some aren’t satisfied with changing the way we measure it. They’re questioning whether it’s a fundamental part of the universe at all.

For one, there’s an extremely small interval called Planck time. To get some idea of the scale, picture a grain of sand. Now imagine that the Earth, our solar system, and everything beyond it are nothing but a giant sand ball. Try to contemplate how many individual grains that would involve. Probably a lot. We’re going for a general sense of smallness here; I haven’t counted the sand.

A single second contains an unimaginably large number of Planck times. This may be a little hard to conceive, particularly if you’re wondering how anyone managed to push the button on a stopwatch that fast. Thankfully, this is a calculated scale, not a stopwatch measurement. Take a second and boggle your mind with the concept before moving on.

Done yet? Good. Here’s what those meddling physicists are up to. At this scale, our current theories can no longer reliably describe space and time together. That doesn’t mean the universe simply ceases to exist, although it would have made my argument considerably easier. It means the rules we use to explain it stop being sufficient. The building blocks of what we feel and touch, and even the method we use to measure how long it takes to properly burn a DiGiorno pizza, become a lot less straightforward.

To make things worse, those pesky physicists have been ambushing time with mathematics. John Wheeler and Bryce DeWitt developed an equation as part of an attempt to reconcile general relativity with quantum mechanics. What does this have to do with time? Well, time as we ordinarily understand it is conspicuously absent from the equation. Physicists are still arguing about what to make of that. I’m mostly concerned that the Benjamins I spent on a fancy digital watch could have been better spent elsewhere.

Then again, maybe it doesn’t matter. Maybe, just maybe, those Benjamins aren’t quite what they seem either, and my hard-earned cash wasn’t wasted. To investigate that possibility, we have to consider atoms. Yes, those small things made famous by the ’60s cartoon superhero Atom Ant.

Let’s start by thinking of atoms as little billiard balls piled together to construct rocks, trees, and virtually everything in the observable universe. This is a perfectly comfortable picture of matter, which should have been our first indication that physics wouldn’t leave it alone.

In 1900, Max Planck’s work on the radiation emitted by heated objects helped set the stage for quantum physics. What followed was considerably stranger than a collection of tiny billiard balls. Atoms have smaller components, and the behavior of those components bears very little resemblance to anything you might encounter on a pool table. There are quarks, electrons, bosons, and a whole bunch of other things whose behavior makes solid matter seem like an unnecessarily confident name for the finished product.

Why is this important to you? Well, as you may have found out by now, your body is made up of different parts: a couple of lungs, a leg, probably a liver, a fully functioning brain, I’m assuming. These parts are made up of cells. If you took a science course in high school, you probably also know that those cells are themselves made up of atoms. This doesn’t prove you don’t exist. It does suggest that whatever you are is considerably less solid and sensible than you might prefer.

Now that we have established that physics is doing very little to make us comfortable, it’s probably best to take an intermission. Let it all soak in and percolate for a while. Go grab a coffee and relax for a bit. Don’t worry, this isn’t going anywhere. Just prepare yourself, because it’s about to get philosophical up in here.

Now that you’re hopefully back from your break, it’s time to use your imagination again. If you’ve seen The Matrix, try recalling the scene where Morpheus breaks the news to Neo that he has been living in a simulation all his life. His point is that everything Neo considers real reaches him through signals interpreted by his brain.

This isn’t entirely a screenwriter’s invention. Our experience of the world depends on the brain interpreting signals from our senses. We don’t get to step outside that process and inspect reality directly, which seems like an oversight.

Since this is the case, is it hard to imagine that video games might someday be able to hijack those sensory inputs to let us play Grand Theft Auto or the latest version of Barbie Horse Adventures?

Let us take this a step further and imagine a demented individual keeping a brain in a container, connected to a computer that simulates a complete environment. This environment might include a small town, a wife, a son, all the things you and I consider normal. From the brain’s point of view, everything is normal, even the European convertible breaking down and the obnoxious friend who shut off the air conditioner one hot summer day. The brain is quite deceived about its world. It even believes it has a body and is reading some twisted essay that it knows, deep down, isn’t right.

Thankfully, philosopher Nick Bostrom offers another possibility. We might not need the container at all. We could be part of a computer simulation, right down to the brains we’re using to object to the idea.

His simulation argument proposes that at least one of the following is true:

1. Humanity is very likely to go extinct before reaching a stage capable of creating these simulations.
2. Civilizations that reach that stage are extremely unlikely to run significant numbers of simulations of their evolutionary history.
3. We are almost certainly living in a computer simulation.

For the sake of argument, this advanced, or “posthuman,” stage would involve enough computing power to simulate worlds full of billions of inhabitants, each with a conscious experience of being there. Whether that’s possible is a fairly important question. For now, let us assume it is and see how much worse things can get.

The bright side is that the third proposition isn’t a conclusion we can simply declare true. The argument depends on what happens with the first two. If civilizations generally go extinct before they can build these simulations, or survive but have very little interest in running them, there may not be many simulated people around.

In other words, humanity losing interest in itself or failing to survive could improve your chances of being an original. It’s difficult to know which part of that to feel good about.

This may seem a little depressing. In fact, believing you’re already a simulation might help soothe the emotional pain. Or is it better to have existed and lost than never to have existed at all? Either way, I think an explanation of how the simulations might come to outnumber the originals is needed.

Let us consider a civilization that already has the power to run simulations of its history and has done so. Is it likely to stop at one? Might it run several for more accurate results, or simply because someone wants to see what happens? If the simulated inhabitants can eventually run simulations of their own, things become even more crowded.

If you’ve mentally answered yes to any of these questions, the ratio of simulated people to original people is already stacking up against you. The more simulations there are, the less obvious it becomes that you should happen to be among the originals. This depends on quite a few assumptions, but none of them are particularly comforting once you’ve agreed to entertain them.

When considering games such as The Sims, where you control the actions of ordinary people within a virtual world, it doesn’t seem like much of a stretch to imagine ourselves as part of a nine-year-old’s video game.

Let’s just hope he doesn’t get his dad to buy the Godzilla add-on.

It’s a good thing to keep in mind that established physics, unanswered questions, and philosophical arguments aren’t all the same thing. Time dilation has experimental evidence behind it. The idea that we’re characters in someone else’s computer is considerably harder to test. Neither establishes that we don’t exist, although both make the question of how we exist more interesting than it first appeared.

Our understanding of the universe has changed before and will change again. Newton’s ideas worked remarkably well, and still do in many circumstances, but Einstein showed where they needed extending. The human race is on an epic quest to find all the answers to the universe, and we are bound to make a few mistakes along the way.

Personally, I don’t think it matters much whether our universe is the original or a very convincing imitation. I still have things I want to do, and being made of unfamiliar physics or someone else’s computer code doesn’t seem like a good reason to stop.

Although, if someone is controlling all of this, I’d appreciate a little more notice before the pizza burns.