9.1 Distributed Consensus (Objectivity as Nash Equilibrium)

(Distributed Consensus - Objectivity as Nash Equilibrium)

“If the world is generated for you, why is the red light I see also your red light? Because objective reality is not a single truth, but consensus reached by countless players in interaction. Physical laws are that huge distributed ledger.”

We said earlier that the world is generated for you (UI theory). But this has a big Bug: Solipsism. If the world is generated by you, who am I? Am I an NPC? If I’m also a player, I want the cat dead, you want it alive, who does the server listen to?

This chapter upgrades single-player mode to multiplayer mode. We will prove: So-called objective reality is just consensus reached by multi-agent systems.

9.1.1 Wigner’s Friend: Version Conflict

Quantum mechanics has a paradox called Wigner’s Friend:

• Friend in lab sees cat alive (version A).
• Wigner outside door thinks friend is in superposition state of “seeing dead cat” and “seeing alive cat” (version B).

If everyone has their own private reality, the world would have split into countless parallel dreams long ago. Since we can chat in one world, the system runs a strict synchronization protocol.

9.1.2 Reality Is Intersection of Perspectives

Definition 9.1.1 (Objective Reality)

Objective reality is neither God’s perspective nor your private perspective. Objective reality is the greatest common divisor (intersection) of all player perspectives.

$$Real={\text{View}}_{\text{A}}\cap {\text{View}}_{\text{B}}\cap {\text{View}}_{\text{C}}\dots$$

Like World of Warcraft server:

• Player A sees a tree.
• Player B sees that tree.
• System only maintains one “tree” object and broadcasts its reference to everyone.

Only states jointly locked (observed) by multiple players are “hard” physical reality. Hallucinations in your brain because only you see them (no consensus) are judged “illusory” by the system.

9.1.3 Bayesian Update: Wave Function Synchronization

How is consensus reached? Through chat (information exchange).

1. Initial: I think electron is left, you think right (belief conflict).
2. Interaction: You shout to me: “I caught it on the right!”
3. Synchronization: I receive information. If I trust you (treat you as reliable measuring instrument), I update my probability distribution.
4. Result: My wave function also instantly collapses to the right.

Theorem 9.1.1 (Consensus Convergence)

As long as everyone is reasonable (follows Bayesian rules), everyone’s wave functions rapidly converge to a globally consistent state. This state is called “objective fact.”

9.1.4 Physical Laws Are Nash Equilibrium

Why does consensus always converge to physical laws ($F=ma$), not magic? This is a result of game theory.

Treat the universe as a prediction game. Everyone guesses what happens next second.

• If everyone guesses randomly, error is huge.
• If everyone agrees on a stable rule (like stones fall down), everyone’s prediction error is minimized.

Newton’s laws are not truth; they are evolutionarily stable strategies (ESS). That player who believed “stones fly up” was eliminated long ago due to prediction errors (crushed by stones). Surviving players all have the same physics engine in their brains.

9.1.5 Universe Is Blockchain

To engineers, this is blockchain.

1. Blocks: Every physical event that occurs (collapse).
2. Hash chain: Causality. Present must contain past information.
3. Consensus mechanism:
   • Proof of Work (PoW): To change reality, you must consume energy (do work). Prevents someone from modifying data with thoughts.
   • Broadcast: Light speed $c$ is network latency. Once any event occurs, light speed broadcasts to entire server.
   • Confirmation: Once information is recorded by environment, block is confirmed, becomes unchangeable history.

Conclusion:

We are not alone. So-called “objective world” is a decentralized, tamper-proof shared document maintained by all of us living beings. We are both readers and authors.