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LESSON 4 · The Mental Models Playbook

Genuine Complexity Exists

Some phenomena are genuinely complex. The 2008 financial crisis had multiple interacting causes — regulation, incentives, psychology, and global capital flows. Insisting on a single simple explanation misses the systemic nature of the event. Occam's Razor says prefer simplicity, not demand it.

The test is not which explanation sounds simplest, but which explanation requires the fewest unverified assumptions. A single-cause story often hides dozens of implicit claims. A multi-cause story that names each factor honestly may actually be the more parsimonious model, even if the sentence is longer.