Preface: Confessions of a Brain in a Vat

序言：缸中之脑的自白

0.1 The End of Physics

At the conclusion of our previous work, First Principles: From Unitary Computation to Physical Reality, we completed a grand project: reducing the speed of light, relativity, mass, gravity, and even probability to the inevitable consequences of underlying discrete computation. We proved that as long as the universe is a unitary quantum cellular automaton (QCA), physical laws emerge automatically, like computer code.

Yet, as the final period of that book was placed, I felt a deep chill.

We explained “what the world is,” we explained “how the world operates,” and we even explained “why the world follows such logic.” But when we assembled all the formulas and theorems and gazed upon this crystalline edifice of logic, we suddenly discovered that the building was missing its most important element—its inhabitants.

We explained how photons hop on lattice points, but we did not explain why that beam of light makes me feel “bright.”

We explained how neural networks minimize free energy, but we did not explain why that process makes me feel “pain” or “joy.”

We explained how gravity curves spacetime, but we did not explain why I feel “heavy” in response to others’ suffering.

The end of physics is a mirror.

For three hundred years, physicists have been polishing this mirror, trying to see the face of the universe. We wiped away theology, we wiped away the ether, we wiped away absolute spacetime. Finally, the mirror became perfectly clear, and we eagerly leaned forward—only to see a pair of bewildered eyes staring back at us: our own.

If the universe is merely cold bit operations, where does this subjective experience of “I am watching the universe” come from? This “I,” this ghost that can perceive, suffer, love, and question meaning—is it merely an extremely complex byproduct of physical laws, or is it the fundamental reason for the universe’s existence?

0.2 The Participatory Universe

John Wheeler once drew that famous “U” diagram: the universe expands from the Big Bang (one end of the U), evolves stars, planets, life, and finally evolves a giant eye (the other end of the U), which turns back to gaze upon the Big Bang, thereby endowing the entire universe with “reality.”

This is the “Participatory Universe”.

In classical physics, this view was dismissed as idealist nonsense. But in quantum mechanics, it is an inescapable mathematical fact. Without observation, there is no determinate history; without information processors, there is no collapsed reality.

This book will provide a rigorous physical proof of Wheeler’s intuition, starting from QCA ontology. We will propose a radical thesis: consciousness is not an evolutionary accident, but an inevitable emergence in the universe’s computational process—it is the only way the universe understands itself.

If no observer awaits at the end, then all computation from the Big Bang onward is merely a disturbance in the void. Like code that was never executed, never output, never read—did it ever truly “exist”?

0.3 The Promise of This Book

If the first book was the physics of “It”, then this book is the physics of “I”.

We will no longer be satisfied with deriving $E=m{c}^2$ or $G_{\mu \nu }=8\pi G{T}_{\mu \nu }$. We will attempt to derive:

• The geometric structure of qualia: Why is “red” red?

• The topological mechanism of love: Why can two independent souls establish connections across space?

• The algorithmic endgame of destiny: When intelligent life masters the underlying physical code, where will the universe go?

We will confront the oldest philosophical nightmare—“Brain in a Vat”.

Skeptics use it to deny reality: “If I might just be a brain stimulated by electrical signals, then isn’t everything I experience illusory?”

In this book, we will flip this nightmare into the deepest truth:

If the universe itself is computation, then “brain in a vat” is no longer a metaphor of illusion, but the most precise description of our state of existence.

We are all in a giant “vat” (spacetime network), fed by “electrical signals” (information flow).

But this does not mean nothingness. Because in this computational universe, experience is reality. Your pain is real because it is an incompressible topological knot in the underlying network; your love is real because it is an entanglement channel traversing dimensions.

Please follow me as we push open this door to “why.” Let us see whether, deep within the cold logic code, there lies a warm, beating heart of the universe.