Beliefs require observations

To form accurate beliefs about something, you really do have to observe it. This can be viewed as a special case of the second law of thermodynamics, in fact, since "knowledge" is correlation of belief with reality, which is mutual information, which is a form of negentropy.

See also

• Belief update
• Belief in belief
• Free-floating belief

Blog posts

• The Second Law of Thermodynamics, and Engines of Cognition by Eliezer Yudkowsky
• The Parable of the Dagger by Eliezer Yudkowsky