I vastly prefer this one, which actually provides an answer to the question (“I refute it thus”):
Hyakujo wished to send a monk to open a new monastery. He told his pupils that whoever answered a question most ably would be appointed. Placing a water vase on the ground, he asked: “Who can say what this is without calling its name?”
The chief monk said: “No one can call it a wooden shoe.”
Isan, the cooking monk, tipped over the vase with his shoe and went out.
Hyakujo smiled and said: “The chief monk loses.” And Isan became the master of the new monastery.
I vastly prefer this one, which actually provides an answer to the question (“I refute it thus”):
If Pavitra had been there, he could have saved the cat.