A learned man once went to a Zen master to inquire
about Zen. As the Zen master talked, the learned man
would frequently interrupted him with remarks like,
"Oh yes, we have that too....", etc.
Finally the Zen master stopped talking and began to
serve tea to the learned man; however, he kept on pour-
ing until the tea cup over flowed.
"Enough, no more can go into the cup!" the learned man
"Indeed I see," answered the Zen master. "If you do not
first empty your cup, how can you taste my cup of tea?