Spontaneous Collapse Theories and Temporal Primitivism about Time's Direction

Area of Science:

• * Foundational Physics
• * Quantum Mechanics
• * Philosophy of Time

Background:

• * The direction of time is debated: either a fundamental property (primitivism) or derived from a directionless reality (non-primitivism).
• * Non-primitivism is favored due to time-reversal invariant fundamental dynamical laws.
• * This paper explores arguments for primitivism in the quantum realm.

Purpose of the Study:

• * To provide grounds for supporting a primitive direction of time within quantum theory.
• * To leverage the underdetermination of quantum theories to support primitivism.
• * To demonstrate how spontaneous collapse theories can ground a primitive direction of time.

Main Methods:

• * Analysis of metaphysical and dynamical underdetermination in quantum theories.
• * Examination of spontaneous collapse theories, specifically the Ghirardi-Rimini-Weber (GRW) model and Continuous Spontaneous Localization (CSL).
• * Investigation of the time-reversal properties of the ontology in GRW with a matter-density field (GRWm).

Main Results:

• * Spontaneous collapse theories, when their ontology is considered, are not invariant under time reversal.
• * The GRWm model provides a framework where the ontology exhibits a clear direction of time.
• * This non-invariance supports the primitivist view of time's direction.

Conclusions:

• * A primitive direction of time can be defended within the quantum realm.
• * Spontaneous collapse theories offer a viable foundation for quantum primitivism.
• * The GRWm model illustrates how a fundamental direction of time emerges in quantum processes.