Mu problem

The "Mu problem" is a philosophical and logical dilemma that arises in the context of Zen Buddhism, particularly in relation to the concept of non-duality and the nature of questions and answers. The term "Mu" translates to "no," "not," or "nothingness" in Japanese, and it is often associated with the teachings of Zen master Joshu (or Zhaozhou) in a famous koan.