Emptiness

This, to me, is the beginning of learning. Dismissing what you think you already know and becoming as a blank sheet of paper; becoming as a vessel hollowed out, ready to contain something of sustenance.

Perhaps emptiness itself.
Those who practice mediation may refer to the state of No Mind. This is a space of calm where new insights are achieved without the influence of external sensory. This state is similarly used in the martial arts to achieve unison with both the attacker and situation. Explains Journeyman over at Japanese Jiu Jitsu (see Randori):
“This state of no-mindedness is called Mushin in Japanese and it is a state we should all strive to attain. When the mind is empty, it is free to respond instantly to any attack.”
This resonates with the teachings of Aikido founder Morihei Ueshiba, who is quoted in his manual The Art of Peace:
“Cast off limiting thoughts and return to emptiness. Stand in the midst of the Great Void. This is the secret of the way of a warrior.”
He continues to say that a warrior of peace contests nothing and that “Defeat means to defeat the mind of contention that we harbour within.”