Wuzhun's "Cypress Tree"
A monk asked Zhaozhou, "
Does a dog have Buddha-nature or not?" Zhaozhou answered, "Wu." The monk was unsatisfied and asked,
"All sentient beings have Buddha-nature.
Why does a dog not have it?" Zhaozhou replied,
"Because it has karmic consciousness."
Reflection
Wuzhun's 'Cypress Tree' combines Zhaozhou's Mu with a second answer about karmic consciousness. The apparent contradiction between 'Wu' for the dog and the explanation that dogs lack Buddha-nature due to karmic consciousness shatters conceptual attachment to doctrinal statements. The koan forces the practitioner to go beyond logic to direct realization.