知不知，上；不知知，病。
§71 #1To know when one does not know is best.#2 To think one knows when one does not know is a dire disease.
夫唯病病，是以不病。
Only he who recognizes this disease as a disease can cure himself of the disease.
圣人不病，以其病病，是以不病。
The Sage's way of curing disease also consists in making people recognize their diseases as diseases and thus ceasing to be diseased.