Half a century ago, Stern discussed this attribute of an artistic object and called it apparency. While art is not limited to this single end, he felt that one of its two basic functions was "to create images which by clarity and harmony of form fulfill the need for vividly comprehensible appearance." In his mind, this was an essential first step toward the expression of inner meaning.
The personal experience of most of us will testify to this persistence of an illusory image long after its inadequacy is conceptually realized. We stare into the jungle and see only the sunlight on the green leaves, but a warning noise tells us that an animal is hidden there. The observer then learns to interpret the scene by singling out "give-away" clues and by reweighting previous signals. The camouflaged animal may now be picked up by the reflection of its eyes. Finally by repeated experience the entire pattern of perception is changed, and the observer need no longer consciously search for give-aways, or add new data to an old framework. They have achieved an image which will operate successfully in the new situation, seeming natural and right. Quite suddenly the hidden animal appears among the leaves, "as plain as day."
Everything points to the conclusion that the phrase 'the language of art' is more than a loose metaphor, that even to describe the visible world in images we need a developed system of schemata.
It is related that the bodhisattva Manjusri was once standing at the gate, and seeing him, Shakyamuni Buddha called to him, "Manju, Manju, why don't you come inside the gate?"
Manjusri replied, "I don't see anything outside the gate."
When you once attain true self-realization, these barriers disappear in an instant as though they were nothing but mirages, and you will find that from the very beginning you have always been in a world where there is neither inside nor outside. That is what "gateless" means. Therefore, all koans are impassable barriers for those who are unenlightened, but for the enlightened there is no gate at all. They can come and go quite freely.
One day, as Kyogen was clearing the undergrowth, a pebble bounced off the tip of his broom and resounded against a bamboo tree. Hearing the sound, he suddenly experienced great enlightement. The first stanza of the poem he composed on this occasion is very famous:
One striking sound,
and I have forgotten all I knew.