22.3 Objective Reality as Nash Equilibrium: Game-Theoretic Fixed Point of Inter-Agent Information Exchange
In Section 22.2, we re-expressed gravitational interactions as Bayesian flows generated by observers to minimize cognitive disagreement (relative entropy). This dynamical description explains the process of consensus formation, but has not answered what the final state of consensus is. Why doesn’t this flow fall into endless chaotic oscillations? Why do we converge to an extremely stable “objective reality” that seems independent of any single observer?
This section will introduce game-theoretic framework, proving that Objective Reality is essentially Nash Equilibrium in multi-agent cognitive games. At this equilibrium point, no observer can reduce prediction error by unilaterally changing its internal model. The “iron law” nature of physical laws is actually manifestation of Stability and Rigidity of this statistical equilibrium state.
22.3.1 The Reality Game: Definition and Payoff Function
Consider observer network in QCA universe. Each observer is an agent attempting to minimize its own variational free energy (see Chapter 19).
In multi-agent environments, observer’s sensory input comes not only from non-intelligent environmental background, but also from actions of other observers (as communication or physical interaction). Therefore, observer ‘s free energy depends not only on its own model , but also couples with neighbors’ models .
Definition 22.3.1 (Reality Game)
Reality Game is a non-cooperative game, consisting of:
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Players: Observer set .
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Strategy Space: Each observer’s internal predictive model space . Strategy is choosing a density matrix (representing worldview).
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Cost Function (Negative Payoff): Each observer’s total free energy , containing two parts:
where represents strategy set of all observers except , is prediction error for “hard” physical environmental data, is cognitive disagreement with neighbors (Bayesian gravitational potential).
22.3.2 Objective Reality as Nash Equilibrium
Observers continuously correct to minimize . When system evolution stops, it means everyone has found optimal model for current environment and others.
Definition 22.3.2 (Objective Consensus State)
A joint model state is called Objective Consensus State if it constitutes Nash Equilibrium of Reality Game. That is, for any observer and any possible alternative model :
This means, when everyone else adheres to current “reality,” no single observer can gain survival advantage (lower free energy) by “creating illusions” (deviating from consensus).
Theorem 22.3.1 (Reality Stability Theorem)
In QCA networks, if connectivity is sufficiently high and communication delay sufficiently small, Bayesian gravity flow will converge to an Evolutionarily Stable Strategy (ESS). The shared model structure corresponding to this stable fixed point is Objective Reality.
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Objectivity: Not “independent of observers,” but “consistently optimal solution for all observers.”
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Resistance: If some observer attempts to deny reality (e.g., believing “I can walk through walls”), their prediction error will sharply increase (hitting wall), or social coordination cost surges (seen as insane). Nash equilibrium’s potential well forces them back to consensus.
22.3.3 Origin of Physical Laws: Structural Constraints of Equilibrium
In this framework, what are physical laws (such as energy conservation, speed of light limit)? They are Structural Constraints of Nash Equilibrium.
Corollary 22.3.2 (Laws as Protocols)
Physical laws are a set of Meta-protocols reached by observer groups through long evolutionary games. This protocol achieves maximum prediction accuracy across the network with minimum computational cost (minimum complexity).
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Newton’s Laws: An efficient consensus protocol for coordinating motion predictions of macroscopic objects.
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Quantum Mechanics: A more fundamental protocol handling uncertainty in microscopic information exchange.
Why the entire universe follows the same set of laws is because in a strongly connected causal network, Unified Standardization is the globally optimal solution for reducing network-wide communication entropy (disagreement cost). If one part of the universe follows law A and another follows law B, huge prediction errors (cognitive friction) at boundaries will drive them to merge or isolate.
22.3.4 Unity of Idealism and Materialism: “Hardness” of Consensus
This explains why subjectively constructed reality appears so “hard” and “materialized.”
Definition 22.3.3 (Hardness of Reality)
“Hardness” of reality measures energy cost required to change consensus state.
For a macroscopic object containing particles, its state is “locked” by microscopic observers (particles themselves and environment) through mutual entanglement.
To change this reality (e.g., make a table disappear), you need to simultaneously destroy Nash equilibrium among these microscopic agents. This Inertia of Consensus is extremely huge; for any single macroscopic observer, it manifests as unviolable Material Entity.
Conclusion
Objective reality is not a stage granted by God, but stable standing wave of the web of sentient beings (observers).
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Mechanism: Through games minimizing free energy.
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Result: Nash equilibrium state.
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Experience: This unshakeability of equilibrium is experienced by us as “objective material world.”
At this point, we have resolved consistency problems of multi-agent systems. In the next section 22.4, we will explore how this consensus is encoded and propagated—Physical Essence of Language and Knowledge Graphs. We will see that language is not just a communication tool; it is Tensor Network States flowing on QCA networks.