
A Thousand Brains
11 minA New Theory of Intelligence
Introduction
Narrator: What if everything you perceive—the feel of a coffee cup in your hand, the sound of a familiar voice, the very structure of reality—is not real? What if it's all a model, a simulation running inside your skull? In 1979, Francis Crick, the co-discoverer of DNA, observed that neuroscience was drowning in data but lacked a unifying theory. We had thousands of puzzle pieces about the brain, but no one knew how they fit together. What if the solution to this puzzle, the fundamental algorithm of intelligence, was hiding in plain sight, in the simple act of moving a finger across a surface?
In his book A Thousand Brains: A New Theory of Intelligence, neuroscientist and entrepreneur Jeff Hawkins proposes a groundbreaking framework that attempts to solve this puzzle. He argues that our brain doesn't build one single model of the world, but thousands of them simultaneously. This theory not only redefines our understanding of the neocortex but also has profound implications for the future of artificial intelligence and the existential risks posed by our own human nature.
The Thousand Brains Theory: Your Brain is Not One Model, But Many
Key Insight 1
Narrator: The traditional view of the brain often describes the neocortex—the wrinkled, outer layer responsible for intelligence—as a single, complex hierarchy. Information is thought to flow from the bottom up, with neurons detecting simple features like lines and edges, which are then assembled into more complex objects like faces and cars at higher levels. Hawkins argues this model is fundamentally flawed. It fails to explain how we perceive the world as a stable, unified whole, or how we can recognize an object from any angle with just a few sensory inputs.
The Thousand Brains Theory proposes a radical alternative: the neocortex is composed of approximately 150,000 cortical columns, and each one learns a complete model of an object. Imagine a team of explorers dropped into different parts of a town. One sees a library, another a coffee shop, and a third a rose garden. Individually, their information is incomplete and ambiguous; there could be many towns with a library. But when they communicate and "vote," they quickly reach a consensus: only one town appears on everyone's list.
Hawkins suggests our brain works in a similar way. When you touch a coffee cup, thousands of columns—each receiving input from a different patch of skin on your fingers—are activated. Each column learns its own model of the cup. Through long-range connections, these columns vote, rapidly converging on a single, stable perception of "coffee cup." This explains why our perception is so robust. Even if some columns are damaged or receive incomplete information, the consensus of the thousands of others ensures we still recognize the object. This distributed system of knowledge means there is no single "grandmother cell" in the brain, but rather thousands of models of your grandmother, distributed across the neocortex.
The Secret Ingredient: Thinking is a Form of Movement
Key Insight 2
Narrator: If every cortical column learns a model of the world, how does it do it? The answer, according to Hawkins, lies in a concept he calls reference frames. The brain doesn't learn what an object is by passively receiving sensory data; it learns by moving and observing how that sensory input changes.
Consider learning about a new object, like a stapler, with your eyes closed. A single touch tells you very little. But as you move your finger across it, your brain isn't just processing the texture; it's tracking the location of that sensation relative to the stapler itself. Your brain builds a reference frame, a sort of internal GPS, for the object. It learns that a smooth surface is located at the top, a sharp edge is at the front, and a hinge is at the back. Once this model is learned, your brain can make predictions. If you feel the hinge, your brain predicts that if you move your finger forward, you will feel the sharp edge. For the brain, thinking is a form of movement through these reference frames.
This principle extends beyond physical objects to abstract concepts. Hawkins argues that high-level thought, such as understanding mathematics or politics, also relies on reference frames. A mathematician navigates a "space" of equations, where each logical operation is a "movement" to a new location in the frame. A political strategist thinks through a series of actions, moving through a conceptual space of potential outcomes. All knowledge, from the concrete to the abstract, is stored in these map-like structures, and thinking is the process of traversing them.
Rethinking AI: Why Today's Machines Aren't Truly Intelligent
Key Insight 3
Narrator: The Thousand Brains Theory offers a stark critique of modern artificial intelligence. While systems like DeepMind's AlphaGo can defeat the world's best human players at the complex game of Go, Hawkins argues they are not truly intelligent. AlphaGo has no concept of what a "game" or a "board" is. It cannot apply its knowledge to a slightly different game or even recognize a Go board if it's a different size. It is a powerful but brittle system, an "input-output" machine that lacks the flexibility of genuine intelligence.
Hawkins proposes that to build Artificial General Intelligence (AGI), we must abandon the current path and instead build machines based on the principles of the brain. He outlines four essential attributes for any truly intelligent machine: 1. Continuous Learning: It must learn constantly from its interactions with the world, just as humans do, without needing to be taken offline and retrained on massive datasets. 2. Learning via Movement: It must learn through movement, whether physical or virtual, by sensing how its inputs change as it interacts with its environment. 3. Multiple Models: It must possess many complementary models for everything it knows, making its knowledge robust and fault-tolerant. 4. Reference Frames: It must use reference frames to store knowledge, grounding its understanding of concepts in a structural, map-like way.
Without these attributes, AI will remain a collection of clever but narrow tools, incapable of the common-sense reasoning and flexible adaptation that defines true intelligence.
The Real Existential Threat: The Conflict Within Our Own Skulls
Key Insight 4
Narrator: While many fear a future where superintelligent AI poses an existential threat, Hawkins argues that this fear is misplaced. The real danger is not the intelligence we might create, but the intelligence we already possess. The human brain is not a unified system; it's a product of layered evolution, resulting in a fundamental conflict between the "old brain" and the "new brain" (the neocortex).
The old brain, which includes the brainstem and limbic system, evolved to ensure the survival and replication of our genes. It is driven by selfish, short-term impulses: fear, aggression, desire, and dominance. The neocortex, on the other hand, is the seat of reason, long-term planning, and abstract thought. The existential risk arises because our powerful neocortex has created globe-altering technologies—from nuclear weapons to carbon-based economies—but it is often hijacked by the primitive, short-sighted goals of the old brain.
This conflict is the source of our most intractable problems. The old brain's drive to reproduce leads to overpopulation, straining the planet's resources. Its tribal instincts fuel conflict and war. When these ancient drives are armed with modern technology, humanity becomes its own worst enemy. Unlike an AI, which can be designed without these primal motivations, we are stuck with the "ignorant brute" inside our own heads.
A Choice for Humanity: Genes Versus Knowledge
Key Insight 5
Narrator: Given the risks inherent in our own brains, Hawkins concludes by presenting humanity with a profound choice. For millennia, we have been servants to our genes, driven by the evolutionary imperative to replicate. But now, the balance of power is shifting. Our intelligence has given us the ability to understand our own origins and to contemplate a future not dictated by natural selection.
The choice is this: do we continue to favor the old brain and a future defined by the selfish drives of our genes? Or do we favor the new brain and a future defined by the pursuit of knowledge? Hawkins argues that knowledge is a more worthy goal than gene propagation. Genes are just molecules that replicate without direction, while knowledge progresses from ignorance to understanding.
This choice leads to a form of "estate planning for humanity." Recognizing that our species may one day go extinct, we should take steps to preserve our most valuable asset: our knowledge. This could involve creating a "Wiki Earth," a permanent archive of human knowledge stored in satellites, or a "cosmic tombstone," a long-lasting signal to alert other intelligent beings in the galaxy to our existence. Ultimately, the book suggests that the grandest purpose of our intelligence may be to ensure that intelligence itself, and the knowledge it has uncovered, survives—even if we do not.
Conclusion
Narrator: The single most important takeaway from A Thousand Brains is that intelligence is not about raw computational power, but about the ability to learn a predictive, structural model of the world through movement and sensory feedback. The neocortex achieves this not with one master algorithm, but with thousands of columns working in parallel, each building its own model and voting to create a unified perception of reality.
This re-framing of intelligence forces us to look inward. The greatest challenges we face do not come from the hypothetical risks of a future AI, but from the very real and present dangers embedded in our own evolutionary history. The book leaves us with a critical question: What is humanity's ultimate legacy? Is it the propagation of our DNA, or the preservation of the unique understanding our brains have managed to achieve? The answer will determine whether our intelligence is the universe's greatest triumph or its most tragic, self-inflicted failure.