Scott Alexander attempts to understand and explain Karl Friston's complex 'free energy' principle in neuroscience, exploring its various interpretations and potential implications. Longer summary

Scott Alexander explores Karl Friston's work on 'free energy', a complex concept in neuroscience that has been described as a unified brain theory. The post delves into various interpretations of free energy, from its mathematical origins in Bayesian equations to its application in explaining perception, cognition, homeostasis, and action. Scott struggles to fully grasp the concept, acknowledging its complexity and the widespread difficulty in understanding Friston's work. He presents different perspectives on free energy, including its role in uncertainty reduction, its connection to predictive processing, and its potential to explain biological systems and the origin of life. The post concludes with a tentative synthesis of these ideas and raises questions about the implications of the free energy principle for machine ethics. Shorter summary

Scott reviews Will Powers' book on Perceptual Control Theory, finding it convincing for explaining lower-level brain functions but skeptical of its application to higher-level concepts. Longer summary

This post reviews the book 'Behavior: The Control Of Perception' by Will Powers, which presents Perceptual Control Theory (PCT) as a paradigm for understanding human behavior and brain function. The review explains how PCT views the brain as a hierarchy of control systems, from low-level muscle control to high-level abstract concepts. The author finds the theory convincing for lower-level systems but becomes skeptical of its application to higher-level concepts. The review discusses the theory's strengths in explaining certain brain functions and its historical context as a response to Behaviorism, while also pointing out its limitations and potential unfalsifiability at higher levels. Shorter summary