The Single Observer: Why We Stand Alone in Our Minds

The Single Observer: Why We Stand Alone in Our Minds

Every day of every week, humans go about their lives. We sit and eat, watch television, and interact with our friends and families. But can we truly, absolutely prove that the food we eat is real, that the people on the news are real, or that the friends and family you spent your life with even experience things the way you do—or at all?

"Of course the food is real, I can taste it." "Of course my friends experience stuff, they are conscious, aren't they? And we talk all the time!"

These statements may seem like common sense, but ultimately, if you strip away belief and practicality and focus on what can truly be proven, you will find nothing. There is simply no way to prove any of these assumptions to be right or wrong.

You stand alone in your mind.

P-Zombies

For decades, scientists and philosophers have wondered about this topic. For decades, no definitive answer has been revealed. Think about it for a moment: you experience things, right? You can taste, feel, think, and experience. But how can you know if anyone else does? You wave hello to the bus driver and he waves back, you make a joke and people laugh, you insult someone and they get angry. But do they?

The Philosophical Zombie theory says otherwise. Philosophical zombies (p-zombies) are theoretical mindless, insensate beings that are microphysically identical to humans, allowing them to blend right in. They act out emotions and interact normally, yet they are completely experienceless. Who is to say everyone you see is not a p-zombie?

Qualia

Even if we can say for certain that others have consciousness and experiences, we still cannot prove that what someone else experiences isn't unfathomably different from what you experience. These individual, independent instances of subjective experience are known as qualia.

Say, for example, you want to know if your friend sees the colour red the same as you. Simple, right? But how would you ever check?

"Make them point at something red?" Incorrect! From birth, that person has been told that the specific colour they are pointing at is known as "red." This cannot prove that it matches the same red you see.

Similarly, how would you prove that your friend processes and hears language the same way you do?

"Ask them to say a word?" Wrong again! For all we know, when I say the word "Apple," that person may hear what I would know as a completely different word or pure gibberish. When they repeat it back to me, they may say what is to them "Tissue," but I hear "Apple." Again, there is simply zero way to prove otherwise.

Boltzmann Brain

Can we even prove that your friends, even as mindless entities, are real at all?

Think about how genuinely unlikely it is that planets would form in the first place. Even if they do, think about how unlikely it is that they would orbit stars so systematically. As you follow the chain of concepts required for the life you experience and take for granted, think about how impossibly rare they seem: habitable zones, single cells, multicellular life, evolution. What if you—the observer, the experiencer—are just a floating brain in an empty void?

According to the Boltzmann brain thought experiment, this is an exponentially more plausible concept.

The second law of thermodynamics states that entropy, or disorder, is the most natural, probable state of the universe. So how is it that all of this complex cosmic order happened? It is inconceivably improbable. Contrastingly, it would only take a tiny amount of luck—a random fluctuation in energy and particles—to spontaneously form you: a lone "floating brain" in space.

Think about this the next time you talk to someone: is anything real at all?

A Note on the Mystery

While existential concepts like these have stumped the world's greatest scientists, physicists, and philosophers for generations, they ultimately make no difference to our everyday lives.

Tomorrow morning, the coffee will still taste warm, the sun will still feel bright, and the people around you will still look familiar. Even if it is all a beautifully constructed trick inside a floating cosmic brain, the illusion itself is a spectacular ride—and it is ours to watch.