The document explains the Ladder of Inference, which is a tool to help understand unconscious thinking patterns. It describes the steps people take in forming beliefs and making decisions: observing data, selecting certain details, making assumptions based on those details, drawing conclusions from the assumptions, adopting beliefs, and taking action based on those beliefs. An example is provided of how ranchers and a city drew different conclusions about water usage during a drought based on the data they selected and the assumptions they made.