The Free Energy Principle and the Ultimate Simulation: Are Our Brains Already Wired Together?

The Free Energy Principle and the Ultimate Simulation: Are Our Brains Already Wired Together?

One day, my son asked me why people are afraid of the dark. I told him that our brains are always dreaming, even when we’re awake. During the day, this dream aligns with what we see and hear around us. But in darkness, when visual input disappears, the brain starts filling in the blanks on its own.

“But why does it imagine scary things?” he asked.

Perhaps there’s an evolutionary reason for that. Assuming danger lurks in the dark makes us more cautious — a survival instinct. After all, it’s better to be overly careful than to ignore a real threat.

At the time, I didn’t realize this idea had a name: the Free Energy Principle.

The Free Energy Principle suggests that our brain is, at its core, a prediction engine. Its primary role is to anticipate what happens next. From an evolutionary perspective, the reason is simple: if you can foresee a predator’s attack, you have a chance to escape; if you can’t, survival isn’t an option.

Artem Kirsanov created an excellent video explaining the Free Energy Principle. If you’re interested in exploring the concept further, I highly recommend giving it a watch:

The Free Energy Principle suggests that every human brain operates with an internal model of reality — a kind of mental map used to predict the world around us. This model is constantly adjusted based on new sensory input, shaping our perception of reality.

Artem Kirsanov illustrates this concept in his video with a simple but powerful example: a tiger. Imagine spotting yellow and black stripes in the distance. Your brain instantly generates multiple possibilities — it could be a person in a tiger-striped shirt, a child’s lost toy, or an actual tiger. At this stage, there’s uncertainty, which the theory refers to as “free energy.” The brain’s goal is to minimize this uncertainty, reducing the likelihood of surprises.

As more information arrives, our brain narrows down the possibilities. If the striped object moves, we can rule out the toy tiger. Now, the remaining options depend on context — if we’re in a park, it’s probably a person; if we’re on a safari, it’s far more likely to be a real tiger.

This process highlights a crucial idea of the Free Energy Principle: perception isn’t just about passively receiving information; it’s an active process of constructing reality. What we experience is largely shaped by our brain’s internal model, while external sensory input merely helps refine it.

Minimizing Free Energy is somewhat similar to how the wave function collapses in quantum mechanics. In our minds, the perception of the world exists as a superposition of possibilities, which then collapses into a specific experience when influenced by external sensory input. This experience is how we perceive and live reality.

I’ve long been fascinated by a question: What would happen if we stripped away all sensory input and linked human brains directly to each other?

Picture four people lying in isolation tanks, completely cut off from external stimuli. Instead of experiencing the outside world, their minds are connected through an advanced Brain-Computer Interface (BCI). While achieving this is far from simple — both technologically and scientifically — let’s explore the thought experiment.

At the moment of connection, the experience would likely be chaotic, with an overwhelming level of “free energy” due to the lack of structured input. However, since each brain is wired to minimize uncertainty, a kind of equilibrium would eventually emerge. The four minds would synchronize. What would that feel like?

We already know that our brains can generate “reality” without external input — this is what happens when we dream. But what if four people shared the same dream at the same time?

With multiple brains working together to minimize surprises, this collective dream could feel more vivid than any dream we’ve ever experienced — perhaps so real that it would be indistinguishable from actual reality.

When we imagine fully immersive virtual reality, we often assume it will require immense computing power to replicate the physical world. But what if that assumption is wrong? What if we don’t need to simulate reality at all — what if simply connecting our brains is enough, and the mind fills in the rest?

The true metaverse won’t require supercomputers to meticulously simulate the physical world — what we really need are direct connections between human brains.

Figuring out how to “wire” human brains together is no easy task. The most promising approach would likely involve a Brain-Computer Interface (BCI) like Neuralink, which uses electrodes to read and stimulate neural activity. Other possibilities include magnetic field-activated nanoparticles or light-based communication. But entirely new, unconventional methods could also emerge — perhaps even direct biological connections using specialized fungi.

A few years ago, I wrote a full article exploring various BCI solutions:

Imagine a world where people spend most of their lives in fully immersive virtual reality. This shift could significantly reduce human consumption and lessen our environmental impact. With minimal resource usage and optimal distribution of available resources, scarcity, and inequality could disappear, wars could become obsolete, and the exploitation of nature might no longer be necessary.

If you’re interested in diving deeper into this idea, you can read a full article on the topic here:

This raises an intriguing question: if a reality created by linking brains is completely indistinguishable from “real” reality, could it be that we’re already living in such a constructed experience? And just like that, we arrive at the familiar Simulation Hypothesis.

Many studies have attempted to determine whether we’re living in a simulation. Almost all of them focus on identifying the limitations of the hypothetical computer running the simulation, proposing experiments that would push it to its computational limits — forcing it to reveal itself.

But what if there is no computer at all? What if the simulation isn’t running on some external machine but directly within our brains? In that case, proving it would be impossible. No matter what experiment we devise, the results would always align with our expectations, reinforcing the illusion that our world is real.

If we are indeed living in a simulation, then who created it? This is one of the most common questions tied to the Simulation Hypothesis. But perhaps the answer is simpler than we assume — maybe there was no creator at all. Perhaps we have always existed in this interconnected state as a single Boltzmann brain, and the true illusion isn’t the simulation itself, but the belief that we are distinct, separate individuals.

If you’re curious about the Boltzmann brain theory, I’ve written a full article exploring the concept in detail:

The Free Energy Principle is a captivating theory, that bridges neuroscience and artificial intelligence. But its most thrilling implication is that it could give us a deep enough understanding of the brain to effectively “hack” it. Such a breakthrough wouldn’t just help us solve existing problems — it could allow us to create entirely new realities where those problems never arise in the first place.

My other writings are related to this topic: