Overview
Proposed in 2005 by Karl Friston, the free energy principle states that any self-organizing biological or mechanical system maintains existence by minimizing internal surprisal and uncertainty through adaptations to the environment. This means that the self-organizing system must maintain some set of internal states distinct from the outside world but also have boundaries that allow information to pass through. Since the initial proposal, Friston and his colleagues put forward a unified theory that centers the free energy principle as an organizing principle for all self-organizing systems.
History and Etymology
The free energy principle has a long history that spans across the fields psychoanalysis, statistical machine learning, and neuroscience.