Some Minimal Notes on Notation and Minima: A Comment on "How Particular is the Physics of the Free Energy Principle?" by Aguilera, Millidge, Tschantz, and Buckley

TL;DR

This paper critically examines a recent critique of the free energy principle, clarifying ambiguities, addressing misinterpretations, and reaffirming the robustness of the original results within the context of linear systems.

Contribution

The paper provides a detailed commentary that clarifies the critique of the FEP, discusses the interpretation of equations, and defends the validity of the original results.

Findings

The critique's ambiguities are contextualized and addressed.

Misinterpretations of surprisal and free energy are corrected.

The original results of the FEP remain valid after scrutiny.

Abstract

We comment on a technical critique of the free energy principle in linear systems by Aguilera, Millidge, Tschantz, and Buckley, entitled "How Particular is the Physics of the Free Energy Principle?" Aguilera and colleagues identify an ambiguity in the flow of the mode of a system, and we discuss the context for this ambiguity in earlier papers, and their proposal of a more adequate interpretation of these equations. Following that, we discuss a misinterpretation in their treatment of surprisal and variational free energy, especially with respect to their gradients and their minima. In sum, we argue that the results in the target paper are accurate and stand up to rigorous scrutiny; we also highlight that they, nonetheless, do not undermine the FEP.