Systems consist of stocks (accumulations you can measure) and flows (rates of change). The structure of these relationships determines system behavior over time. While people focus on stocks—the amount of money in your account, books in a store, water in a reservoir—it's the flows that matter most. Understanding this distinction is foundational to systems thinking.

Feedback loops are the fundamental mechanisms that create persistent system behavior. Reinforcing loops amplify change exponentially—more leads to more. Balancing loops resist change and seek equilibrium—deviation triggers correction. When one loop dominates, it determines the entire system's trajectory regardless of other forces present.

Complex adaptive systems create something greater than the sum of parts through interactions between components at multiple levels. Lower-level building blocks form higher-level organisms which themselves become building blocks for yet higher levels. The behavior that emerges can't be predicted from studying components in isolation—emergence is genuine and irreducible.

Leverage points are places in a system where small changes produce large impacts. The highest leverage point is transcending paradigms—keeping yourself unattached to any single model so you can shift between frameworks fluidly. Understanding leverage means knowing where to intervene for maximum effect with minimum effort.