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Asymmetry, Abstraction, and Autonomy: Justifying Coarse-Graining in Statistical Mechanics
The British Journal for the Philosophy of Science
|May 13, 2020
Summary
This study reconciles time-symmetry in fundamental physics with irreversible macroscopic processes using the Zwanzig-Zeh-Wallace framework. It offers a new justification for coarse-graining, addressing objections about time-asymmetry in statistical mechanics (SM).
Area of Science:
- Physics
- Statistical Mechanics
- Philosophy of Science
Background:
- Fundamental laws of physics are time-reversal invariant, yet macroscopic processes exhibit irreversibility.
- Reconciling time-symmetry with observed irreversibility is a key challenge in statistical mechanics (SM).
- The Zwanzig-Zeh-Wallace framework offers a method to derive irreversible SM equations from microdynamics.
Purpose of the Study:
- To address criticisms of coarse-graining within the Zwanzig-Zeh-Wallace framework, specifically regarding time-asymmetry.
- To provide an alternative justification for coarse-graining, moving beyond measurement imprecision.
- To explore the implications for the nature of time-asymmetry in statistical mechanics.
Main Methods:
- Analysis of the Zwanzig-Zeh-Wallace framework and its reliance on coarse-graining.
- Critique of the 'measurement imprecision' justification for coarse-graining.
- Development of an alternative justification based on abstraction and autonomy, illustrated with the Game of Life.
Main Results:
- Objections labeling time-asymmetry as 'illusory' or 'anthropocentric' stem from a flawed justification of coarse-graining.
- An alternative justification for coarse-graining, emphasizing abstraction and autonomy, effectively counters these objections.
- The time-asymmetry in statistical mechanics is shown to be weakly emergent.
Conclusions:
- The proposed framework provides a robust reconciliation of time-symmetry and irreversibility in statistical mechanics.
- The findings have implications for understanding inter-theoretic relations and the emergent nature of physical laws.
- Coarse-graining, when properly justified, is a valid tool for constructing irreversible macroscopic descriptions.
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