The Prussian military theorist Carl von Clausewitz made a distinction that most planning frameworks quietly ignore: the difference between a plan and a theory. A plan tells you what to do. A theory tells you why it should work — and therefore what to watch for when it starts to fail. Most mental models we carry around are plans dressed up as theories. They encode a sequence of actions but not the causal structure beneath them, which means when reality diverges, we don't know which assumption broke. Clausewitz called this gap 'friction' — the permanent difference between the map and the territory — and argued that the only generals who survived contact with the enemy were those who had internalized the theory deeply enough to improvise when the plan dissolved. The practical move: for any model you're currently relying on, try to articulate not just what it predicts, but the specific mechanism you believe produces that outcome. That mechanism is where the real load-bearing assumption lives — and it's the first thing to test when results stop matching expectations.

Pick one mental model you've applied more than twice this year. What specific causal claim is it making — and have you ever tested that claim directly, or only assumed it held?

Drawing from Military philosophy / Strategic theory — Carl von Clausewitz