Lectures on the Sūtra of the Collection of the Father and Son (Pitāputrasamāgamanasūtra) (70)

Original text: 大王。云何耳处。谓四大种。所造净色。分别行相。如前所说。大王。诸法解脱。决定现前。如法界空。不可施设。

Explanation: The Buddha said: Great King, what is the ear base? The ear base is the pure material form created by the seeds of the four great elements. Its characteristics are similar to those of the eye base, arising from the combination of the seeds of the four great elements. When the seeds of the four great elements are pure, the ear base is pure, and not even the slightest dharma can be obtained within it. Because the four great elements are empty, the ear base is empty by nature; because the four great elements are liberated, the ear base is intrinsically liberated, and there is no dharma whatsoever that can bind anyone. Great King, all dharmas are intrinsically liberated, and this liberation is revealed and manifested everywhere, just like the emptiness of the one true dharmadhātu—it is naturally so, not something contrived by human beings.

The ear base refers to the ear faculty, including both the outer ear faculty and the inner ear faculty, both of which are formed by the pure four great elements; therefore it is itself a pure material form, without afflictions and without defilement. What is meant by "pure" is that it has no joy, anger, sorrow, or happiness, no craving, no delight, and no aversion. When the ear faculty comes into contact with sound objects, it never says "I like this sound and dislike that sound"; it has no mental activity—neither wholesome nor unwholesome mental activity exists. Defilement lies in the mind being defiled; the ear faculty is not defiled. The four great elements of earth, water, fire, and wind that constitute the ear faculty are empty, and the ear base is also empty; its intrinsic self-nature is utterly unobtainable. The four great elemental natures of earth, water, fire, and wind are utterly unobtainable, and the ear base is likewise unobtainable.