Free Energy Principle

The Free Energy Principle (FEP) is a theoretical framework in computational neuroscience and systems theory proposing that all self-organizing biological systems — from single cells to entire brains — resist disorder by minimizing a quantity called variational free energy: a measure of the mismatch between an internal model of the world and incoming sensory evidence. First systematically articulated by neuroscientist Karl Friston in the early 2000s, the FEP unifies perception, action, learning, and attention under a single imperative: model the causes of your sensory states, and act to make those states conform to your model's predictions. It is, at present, the most ambitious attempt to derive all of cognitive and biological function from a single organizing principle — and its ambition is precisely what makes it controversial.