The carpenter can bring his idea for a piece of furniture to the test by the simple act of making it. The quester can bring his understanding of the teachings to the test by trying them out in actual everyday living. Not before then can he conclusively determine how correctly he has absorbed them, or how utterly foolish and dangerously misleading they themselves may be. Here is the place of the physical plane and the purpose of physical action. Not before then can he have the certainty that they belong to reality, and not merely to his own or someone else's imagination.
-- Notebooks Category 13: Human Experience > Chapter 1: Situation > # 99