"What we observe is not nature itself, but nature exposed to our method of questioning." - Werner Heisenberg

Mental Model: The Heisenberg Uncertainty Principle (The Observer Effect)

In quantum mechanics, it is not possible to simultaneously know both the precise position and the momentum of a particle. Furthermore, the very act of observing a phenomenon changes it.

This mirrors "Goodhart’s Law" in economics: when a measure becomes a target, it ceases to be a good measure. If everyone observes that the Price-to-Book ratio is a reliable indicator of value, capital floods into low P/B stocks, changing the market structure and rendering the metric useless.