Wired\xa0wrote\xa0a good article about\xa0Karl Friston, the neuroscientist whose works I\u2019ve\xa0puzzled over\xa0here before. Raviv writes:
Friston\u2019s free energy principle says that all life\u2026is driven by the same universal imperative\u2026to act in ways that reduce the gulf between your expectations and your sensory inputs. Or, in Fristonian terms, it is to minimize free energy.
Put this way, it\u2019s clearly just perceptual control theory. Powers describes the same insight\xa0like this:
[Action] is the difference between some condition of the situation as the subject sees it, and what we might call a reference condition, as he understands it.
I\u2019d\xa0previously\xa0noticed that these theories had some weird similarities. But I want to go further and say they\u2019re fundamentally the same paradigm. I don\u2019t want to deny that the two theories have developed differently, and I especially don\u2019t want to deny that free energy/predictive coding has done great work building in a lot of Bayesian math that perceptual control theory can\u2019t match. But the foundations are the same.
Why is this of more than historical interest? Because some people (often including me) find free energy/predictive coding very difficult to understand, but find perceptual control theory intuitive. If these are basically the same, then someone who wants to understand free energy can learn perceptual control theory and then a glossary of which concepts match to each other, and save themselves the grief of trying to learn free energy/predictive coding just by reading Friston directly.