A learned man once went to a Zen teacher to find out about Zen.
The teacher willingly complied, and began explaining.
But as his story unfolded,
the learned man frequently interrupted with remarks like,
"Oh, yes, I know that already,"
and "That is of course a part of many philosophies".

Finally,
the Zen teacher stopped talking
and began to serve tea to the learned man.
He filled his guest's cup,
and still kept pouring,
until the cup overflowed.

"Enough", cried the learned man.
"My cup is already full".
"Indeed, so I see," replied the Zen master.
"And if you do not empty it first,
how can you expect to taste my cup of tea."

Zen Philosophy