E4: Generative Models, Variational Free Energy, and Expected Surprise.
The mechanism underlying entropy management is predictive self-organization. The agent maintains a generative model
p(o,s) and an approximate posterior
q(s). Minimizing variational free energy
F tightens beliefs and maximizes evidence.
F = E_q[ ln q(s) − ln p(o,s) ] = D_KL[ q(s) ‖ p(s|o) ] − ln p(o)
Perception refines
q(s) via prediction-error minimization; action (active inference) samples the world to realize preferred observations.