As far as we know, there’s only one way to be conscious, so it’s possible that in that one way we’re all exactly the same. That’s an assumption, but it’s a safer assumption than the alternative. If we assume that we’re all different, and it turns out that we’re actually all the same, that’s a pretty big mistake. But if we’re actually all different, and we’ve been treating each other like we’re all the same, what’s the worst that could happen? Too much compassion and kindness in the world?

What is it that makes humans different from animals? Or that makes one person different from another? A lot of it has to do with what’s happening in our brains, and there are many words that describe that kind of activity—intelligence, thoughts, consciousness, emotions, instinct, and learning, for example—but it’s not clear which ones really capture the difference between individuals or how all these ideas interact or overlap. In this series, I am going to propose some new definitions for these ideas, which hopefully will make it easier to think about how our minds work and how we are different from other living things and each other. Let’s start somewhere relatively straightforward: What term should we use to describe all processes that we’re aware of in our heads?

Cognition: the neurological causes of a conscious agent’s behavior

Cognition is a good term to use. It’s broad enough to catch all the different processes we’re talking about, while also not being so vague that it loses all meaning. The most important term in this definition is “conscious.” That’s because we want to be able to distinguish what makes animals like us interesting, animals which I am calling “conscious agents” because their behavior is affected by their consciousness. Cognition can include a variety of things—learning, intelligence, and emotions, for instance—but what it really highlights is that though consciousness plays an important part in causing our behavior, it’s not the only part. There are lots of things happening in our brains and nervous system, some that we’re aware of but many that we we’re not. Almost all of them, however, appear to interact with or are dependent on consciousness in some way.

There’s a lot we still don’t know about consciousness, and there are a lot of possibilities for how it works and what causes it. In the next couple of articles, I’ll ask if consciousness is a physical phenomenon and how it leads to things having meaning. For now, though, let’s look at a hypothetical scenario about the ways human consciousness could work. Exploring why this scenario could be possible can help us think about how to define consciousness and the other parts of our cognition as well. It will also look at the differences between ourselves and other people.

The Brain Box

Sixty thousand years ago, a small alien ship visited our planet on a scouting mission and found one particularly intelligent species of primates. They also discovered a comet heading toward a collision with this planet. They couldn’t stop the comet, and they didn’t have room on their ship to save many of the animals, but what they were able to do was scan the entire planet and everything on it in incredibly high detail. They were also able to take the brain of one of the early humans for further study. So that’s what they did, and then they headed back to their ship.

The aliens loaded all the data about the planet—its inhabitants, the environment, and the solar system it was part of—into their massive computer and they started making a simulation. Their plan was to run the simulation to see what would’ve become of this intelligent species they’d discovered and the planet they lived on if it hadn’t been wiped out by a cosmic accident. They modeled everything accurately down to the atomic scale, including all the cells and synapses of every species of plant and animal on the planet. The only change they made was deleting the comet so that the simulated planet would have a long and healthy life.

While re-creating these intelligent apes, the aliens realized that it was just a relatively small part of the apes’ brains that created their consciousness and that these intelligent animals had evolved to make especially good use of it. Their conscious brains let them process information very efficiently, allowing the animals to take in a huge amount of varied sensory data. Their consciousness also allowed them to feel joy and hurt and added these experiences on top of everything else. A lot of the brain wasn’t actually creating consciousness, but the part that was turned out to be very useful—it unlocked a whole new way of life that this one species was able to take advantage of.

In fact, their consciousness was so efficient at processing data that simulating it accurately for millions of individuals put a huge strain on the aliens’ hardware. They could easily simulate most of the things in the world, but that one little piece making consciousness was very difficult to model accurately and quickly.

But they had an idea for a shortcut—instead of trying to model consciousness, they’d just use the real thing. They cloned the small part of the primate brain that created consciousness and made thousands of copies of just that one part, each individual copy capable of creating its own consciousness. Then they wired these clumps of neurons together in little life-sustaining boxes with lots of input and output connections and plugged the boxes into their simulation machine. The giant computer handled almost everything, and the little brain boxes created actual consciousnesses, incredibly efficiently, and were responsible for that tiny but important part of the world.

The aliens watched the simulation of Earth develop just like it would have on the real Earth (without the comet). There were parts of real Earthling brains in those boxes, actually experiencing consciousness, believing that they were part of real bodies.

This ended up working very well, and the simulation kept running smoothly and accurately for tens of thousands of years. That simulation created the history we actually know, and as far as we can tell we are actually in that simulation. When one of the animals—one of us—died in the simulation, the machine would turn off that little brain box at the appropriate moment, and the aliens would reset it and save it. Then, when they needed a consciousness when another animal was born, they’d plug the box back in, connect it to the rest of the new baby’s simulated brain, and turn it back on, ready to start fresh. The simulated Earthlings did well for themselves. Their population grew and grew, and the aliens cloned more copies of that consciousness-creating piece of brain, each exactly the same, made more boxes, and plugged them into the simulation—one for each conscious animal on the planet. All the Earthlings experienced the real life they had missed by making use of billions of exact copies of that piece of brain, all in little identical boxes.

This could be our Earth, a giant simulation of nearly everything—the stars and planets, the oceans and plants and dirt, and everything else. The simulation could include most of our bodies, and even most of our brains. All of it could be simulated except for each of our consciousnesses, which could be run by a little box that creates a real self. We experience everything just as if it was real—in fact, at least part of us still is real, the one important part that actually matters. It also happens that, in this hypothetical, the one part that matters is actually exactly the same in all of us, and we just haven’t realized it yet.

What does this mean?

We know that our entire brain isn’t conscious. The part that causes, maintains, or interacts with consciousness might even be a quite small piece. But it’s that piece that matters to every one of us. In a very real sense, that piece is us, and the hypothetical situation above illustrates that fact. If we happened to be in a simulation, everything else could be replaced, changed, or removed, and we’d interpret that change as a change in the real world. This goes all the way down to changes in our bodies, and even in some parts of our own brain. It’s really just the part in each of our brain boxes, housing our experiences and our personalities, that feel like us. Since we can’t tell if we’re in that simulation or not, we can only be sure that that part of us has to be real.

Let’s consider the things we do consciously and the things that happen unconsciously to see where the boundary between “us” and “everything else” might be. For example, when we learn a new language, we have to remember what each word means, the way to use it, and what it should sound like, among other things. That all seems like conscious activity, whereas once we’ve learned a language and are fluent in it, we’re not consciously thinking about how to speak anymore—we simply speak, without having to put attention and effort into it. The same process happens for all kinds of things, for instance, learning how to walk or how to do mathematics. At first, we have to think about what our goal is, remember what we’ve experienced in the past, and pick actions that feel right in each situation. All those actions happen consciously, seem to be part of “us”—they are things happening in our brains that we’re consciously aware of. Then, over time, we stop making choices consciously, or we stop being aware of the choices we’re making as other parts of our brains learn how to do those things. We don’t have to think about how to speak or how to walk—it just happens, and in the simulation it would be happening outside of our little brain box.

Thinking about consciousness like this, as if we were actually little brain boxes in a simulation, helps us ask questions about the real world we actually live in. Is memory a part of consciousness or not? If some alien accidentally switched two of the boxes, and you woke up in someone else’s body, would your memories go with you? Is the part of the brain that stores memories the same as the part that creates consciousness? Or is memory stored in some unconscious part of the brain and recalled when we need it? If your brain box was switched with someone else’s, would you remember your old life at all or would those memories get left behind?

Maybe we shouldn’t even consider the unconscious parts of our brains as “us.” In this hypothetical, that boundary is represented by the edges of the little brain boxes. Unconsciousness and simulation are on the outside, and on the inside are ourselves, the real and conscious parts that create our feeling of identity. There’s some part of our brains where consciousness happens, and then there’s the rest of our brains, our bodies, and everything else in the world. And sprinkled throughout that world are other people, each in their own little brain boxes. How much do we know about what those people are like inside their conscious selves? How much of the real them do we see through all the layers of world and environment and bodies that separate the parts we can be sure are real? Could this hypothetical be accurate? Could we all essentially be copies of each other in this one way?

We all find ourselves born with a certain family in a certain place in a certain country at a certain time, and we also find ourselves with a particular body that works differently than anyone else’s. We can see all these differences, but we can’t directly see anyone else’s consciousness, and so we must at least consider the possibility that every person on Earth, every conscious animal that has ever lived, could have a consciousness that’s essentially an exact copy of ourselves. All of us—all the parts of us that really matter, the parts we’re sure are really real—might be exactly the same, and it’s just the environment that forces us to grow up differently and act differently. We face many options and possibilities throughout our entire lives. We make choices, and the good and bad memories of those choices shape who we turn out to be on the outside. We can see all those differences, but what about our true conscious selves? Are we sure those are different, too?

If we went back in time, we could imagine that the conscious part of my brain had been switched into some other body at birth and then connected to the rest of that body’s nervous system (to handle walking, keeping the heart beating, being fooled by optical illusions, being fluent in languages, and everything else the unconscious parts of our brains do). I would have been born in some other part of the world, and I would’ve grown up, made all the same choices, and had all the same feelings that the other person would’ve had. We can think of it as the aliens just switching two brain boxes at birth, except of course we’re sure that the two boxes had exactly identical brain bits inside. All those boxes start out exactly the same, so it doesn’t matter what consciousness goes into what brain in what body.

Maybe this isn’t how things work in the real world. But in this hypothetical scenario, it’s how it works, and right now, with what we know about our brains and how the world works, it’s impossible to tell if we’re in that simulation or if we’re in the “real world.” It might be that in a very real sense, we’re all exactly the same where it really matters. Maybe when we learn more about our brains and our consciousness it’ll end up that our consciousnesses are all completely different, or maybe we’re just a tiny bit different, or maybe all our consciousness are exactly the same. We should keep that possibility in mind because just the fact that it’s possible should inform the way we think about other people.

Next, let’s take the first couple of steps toward defining what consciousness is and why it’s so important to us. We’ll look at why consciousness has to be a physical thing if the word “physical” is going to mean anything; define consciousness itself; and then explore what “meaning” means. Once we’ve worked on those three, we can tackle other important ideas in human cognition, like “intelligence,” “learning,” “concept,” and “emotion.”