Understand how people came by their opinions.

1. If you ask someone a question, they will probably give you an answer, so think through to whom you should address your questions. 2. Having everyone randomly probe everyone else is an unproductive waste of time. 3. Beware of statements that begin with “I think that . . .” 4. Assess believability by systematically capturing people’s track records over time.

Ray Dalio's Book Principles