It was obvious to the master from the start of the conversation that the professor was not so much interested in learning about Zen as he was in impressing the master with his own opinions and knowledge. As the Zen teacher spoke, the proud man would frequently interrupt him with remarks like "Oh, yes we have that, too" and so on.

Finally, the Zen teacher stopped talking and began to serve tea to the learned man. He poured until the cup was full... and then kept pouring until it overflowed.

"Enough!" the professor once more interrupted. "The cup is overfull, no more will go in!"

"Indeed, I see," answered the Zen teacher. "Like this cup, you are full of your own opinions and speculations. If you do not first empty your cup, how can you taste my cup of tea?"