A free energy principle for a particular physics

TL;DR

This work develops a unified theoretical framework using the free energy principle and Markov blankets to describe the hierarchical organization of physical systems from quantum to classical scales, emphasizing self-organization and inference.

Contribution

It introduces a comprehensive theory connecting quantum, statistical, and classical mechanics through Bayesian mechanics and Markov blankets, highlighting implications for self-organization.

Findings

Unified description of physical scales via free energy principle

Markov blankets facilitate understanding of self-organization

Bayesian mechanics interprets internal states as inferences about external states

Abstract

This monograph attempts a theory of every 'thing' that can be distinguished from other things in a statistical sense. The ensuing statistical independencies, mediated by Markov blankets, speak to a recursive composition of ensembles (of things) at increasingly higher spatiotemporal scales. This decomposition provides a description of small things; e.g., quantum mechanics - via the Schrodinger equation, ensembles of small things - via statistical mechanics and related fluctuation theorems, through to big things - via classical mechanics. These descriptions are complemented with a Bayesian mechanics for autonomous or active things. Although this work provides a formulation of every thing, its main contribution is to examine the implications of Markov blankets for self-organisation to nonequilibrium steady-state. In brief, we recover an information geometry and accompanying free energy principle that allows one to interpret the internal states of something as representing or making inferences about its external states. The ensuing Bayesian mechanics is compatible with quantum, statistical and classical mechanics and may offer a formal description of lifelike particles.