Psychophysical identity and free energy

TL;DR

This paper explores how thermodynamic free energy relates to variational free energy in biological systems, especially the brain, proposing that neuronal encoding must be stochastic and linking these ideas to philosophical and Gestalt theories.

Contribution

It introduces a framework connecting thermodynamic and variational free energies in biological systems, emphasizing the role of stochastic population codes in neural encoding.

Findings

Thermodynamic free energy encodes variational free energy in biological systems.

Neuronal encoding of generative and recognition densities requires stochastic population codes.

Links between free energy principles and philosophical theories of mind and perception are proposed.

Abstract

An approach to implementing variational Bayesian inference in biological systems is considered, under which the thermodynamic free energy of a system directly encodes its variational free energy. In the case of the brain, this assumption places constraints on the neuronal encoding of generative and recognition densities, in particular requiring a stochastic population code. The resulting relationship between thermodynamic and variational free energies is prefigured in mind-brain identity theses in philosophy and in the Gestalt hypothesis of psychophysical isomorphism.