"When the Zen monk Joshu was asked whether a dog had a Buddha nature he said 'Mu,' meaning that if he answered either way he was answering incorrectly."

Joshu was a ninth-century Zen monk, also known as Chao-chou Ts'ung-shen.

Renowned for his pithy sayings, he became a famous teacher due to the very simple way he spoke. His students said that his lips 'emitted light', meaning that the insight was immediate.