How Are the Outer Six Dusts and the Inner Six Dusts Formed?

External sense-objects are called the outer six sense-objects (ṣaḍāyatana). They are transmitted through the outer sense faculties to the inner sense faculties, forming the inner sense-objects. This entire process is entirely the work of the tathāgatagarbha, not the work of the outer and inner sense faculties themselves. The outer and inner sense faculties are composed of the four great elements; they have no function of their own. If no consciousness operates within them, the outer and inner sense faculties are no different from stones, wood, and insentient things. It is precisely because consciousness operates in the outer faculties, the inner faculties, and the physical body of the four great elements that the physical body of the four great elements seems to have function, and the outer and inner sense faculties seem able to transmit material form, acquiring the capacity to receive material form. In fact, all these functions are entirely the work of the tathāgatagarbha. The inherent function of the outer sense faculties is the work of the tathāgatagarbha; the inherent function of the inner sense faculties is the work of the tathāgatagarbha; and the structure of the inner and outer sense faculties was created by the tathāgatagarbha. All the material forms of the outer six sense-objects are also created by the tathāgatagarbha. Therefore, when the tathāgatagarbha transmits the outer six sense-objects through the outer sense faculties into the inner sense faculties, forming the inner six sense-objects, this too is an act of creation by the tathāgatagarbha.

The inner six sense-objects are composed of subtle four great elements and are also produced by the tathāgatagarbha, generated from the seeds of the four great elements. Both the outer and inner sense-objects are accumulations of the seeds of the four great elements. However, the seeds of the four great elements differ: the outer sense-object is the fundamental object, composed of actual seeds of the four great elements, whereas the inner sense-object is not the fundamental object—it is a shadow conjured up based on the outer sense-object, composed of even subtler seeds of the four great elements, with a slightly different structure; that is why it is called a shadow. It is like a mirror: the object outside the mirror is a real thing, called the outer sense-object, while what is inside the mirror is not real material form, and so it is called a shadow. Although it is also composed of the four great elements, this is a bit hard to understand. The shadow and the external shape are identical in appearance, but in essence they are different—there is a distinction.