the word "empty" has a bad rap

an empty tank is not good; neither is an empty
feeling, empty room or empty promise

and there is something sad about an empty chair,
empty mailbox and empty-nester

but in the the spiritual practice of Zen, "empty"
is good thing, a very good thing

an empty cup, for example, is an often used Zen
metaphor

it represents a state of being that Zen practitioners
patiently and persistently seek

the cup represents mind; and it is empty of thoughts,
judgments, likes and dislikes -

Cast off limiting thoughts and return to true
emptiness.
- Morihei Ueshiba

If your mind is empty, it is always ready for
anything; it is open to everything. In the begin-
ner's mind there are many possibilities; in the
expert's mind there are few . . . thoughts limit
our vast mind.
- Shunryu Suzuki

Only throw away likes and dislikes; and every-
thing will be perfectly clear.
- Seung Sahn

and finally, consider this 13th century story, written
by Zen teacher, Muju

During the Meiji era there lived a master called Nan-in.
One day a university professor came to see him, to ask
him about Zen.

Nan-in, being a polite host, served the professor tea.
He poured and, as his visitor’s cup filled, he continued
to pour.

The professor watched the cup overflow and was
perplexed. At first he was too polite to say anything
but eventually he had to stop his host, saying “It is
already full! No more will fit in!”

“Just like the cup, you are full of your own ideas and
speculations.” replied Nan-in. “How can I teach you
about Zen unless you are first emptied?”