pi Chinese term meaning ‘screen’, ‘shelter’, or ‘cover’. Pi is Hsün Tzu’s metaphor for an obscuration or blindness of mind. In this condition the mind is obstructed in its proper functioning, e.g., thinking, remembering, imagining, and judging. In short, a pi is anything that obstructs the mind’s cognitive task. When the mind is in the state of pi, reason is, so to speak, not operating properly. The opposite of pi is clarity of mind, a precondition for the pursuit of knowledge. A.S.C.