In Lesson 2, we introduced the iceberg: events → patterns → structures → mental models.

We've spent most of the course at Level 3 — structures. Feedback loops, stocks and flows, archetypes. These are the mechanisms that produce the patterns we see.

But who built those structures? Why do those particular feedback loops exist? Why are the rules set up the way they are?

The answer is mental models — the deeply held beliefs, assumptions, and frameworks through which people understand the world. Mental models aren't just opinions. They're the invisible architecture that determines what structures get built, what problems get seen, and what solutions feel obvious.