Monday, 29 December 2025

Decoherence: Disappearance or Redistribution?

Decoherence is often treated as the missing link between the quantum and classical realms — the mechanism by which a system, once entangled with its environment, begins to behave “classically.”

But while decoherence has been invoked to explain why quantum systems appear to lose their weirdness, it does not resolve the foundational paradoxes of quantum mechanics. It merely reframes them — often without dislodging their ontological baggage.

From a relational perspective, decoherence is not about a loss of quantum-ness, but about a redistribution of coherence across a broader configuration of constraints.


1. Standard Interpretation

According to standard accounts, decoherence occurs when:

  • A quantum system becomes entangled with its environment,

  • The system’s phase relationships (coherence) become delocalised,

  • Interference effects vanish for all practical purposes (FAPP).

As a result, the system appears to behave classically, even though no measurement has taken place.

But this account already assumes:

  • A meaningful system–environment distinction,

  • An observer able to track the system in isolation,

  • A collapse-like interpretation of state reduction — now shifted to the environment.

In other words: decoherence doesn’t eliminate the measurement problem —
it reassigns it.


2. Coherence as Relational Alignment

In a relational ontology, coherence is not a property of isolated systems.
It is a pattern of alignment across a field of potential under constraint.

  • A “quantum” system is not a self-contained entity with superposed states,

  • It is a constrained configuration within a broader set of affordances,

  • Coherence is not a fragile internal feature but a relational effect.

Decoherence, then, is not the loss of this coherence, but a redistribution of alignment — a transformation in which the system's capacity for certain actualisations becomes dispersed across its interactions.


3. No Hidden Classicality

Standard accounts often treat decoherence as revealing an underlying classicality that had been suppressed.

But this rests on a metaphysical assumption:

That classical outcomes exist as definite facts waiting to be revealed
once interference is “washed away.”

In relational terms, this is backwards.
There is no classical core to uncover.
There is only a shift in the topology of potential:

  • As constraints widen (e.g. through entanglement), the range of actualisable outcomes changes.

  • What appears as classical behaviour is not recovered — it is reconstrued from a new perspective within a distributed field.


4. The Fiction of the Isolated System

A key premise in decoherence theory is the existence of an “isolated quantum system” that becomes coupled to an “environment.”

But such a division is already perspectival.
It presupposes a boundary that is not ontologically fundamental.

From a relational viewpoint:

  • The system is always already embedded in a web of dependencies,

  • What we call “environment” is not external noise, but an extension of the system’s field,

  • Decoherence is not an intrusion, but a reconfiguration of relevance — a change in which dimensions of the field dominate actualisation.


5. Relational Re-description

We might say:

Decoherence is not the loss of quantum behaviour,
but the redistribution of potential under shifting constraint.

What was visible from one vantage becomes hidden from another — not because it ceased to exist, but because it no longer aligns with the current configuration of relations.

There is no mystery here.
Just the evolution of affordances as fields of meaning reorganise.


Closing

Decoherence doesn’t resolve the quantum-classical divide — it exposes its contingency.
It invites us to abandon the idea that the world is inherently divided into two realms, and instead to ask:

How do different patterns of constraint shape what can become actual?
How do coherence, relevance, and possibility evolve together?

In the next post, we’ll take up the idea of the quantum–classical boundary itself — and ask whether there was ever a boundary to begin with.

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