Series: The Learn Arc — 50 posts teaching Active Inference through a live BEAM-native workbench. Part 1 set the map. This is Part 2. The one-sentence claim Chapter 1 of Active Inference (Parr, Pezzulo, Friston — MIT Press 2022) makes a claim that is audacious in one line and then spends 230 pages proving it: Perception, action, and learning are the same process — running in three directions