How Are the External Six Dusts and Internal Six Dusts Formed?

External dust refers to the external Six Dusts, which are transmitted through the external faculties to the internal faculties, forming internal dust. This entire process is entirely the work of the Tathāgatagarbha, not the external or internal faculties themselves. The external and internal faculties are composed of the Four Great Elements and have no inherent function. Without consciousness arising and functioning within them, the external and internal faculties would be no different from rocks, wood, or other insentient objects. It is precisely because consciousness operates within the external faculties, internal faculties, and the physical body of the Four Great Elements that the body of the Four Great Elements appears to have functions. Thus, the external and internal faculties seem capable of transmitting material forms and possess the function of receiving material forms. In truth, all these functions are entirely the work of the Tathāgatagarbha. The functions of the external faculties themselves are the work of the Tathāgatagarbha, the functions of the internal faculties themselves are the work of the Tathāgatagarbha, and the structure of the internal and external faculties is created by the Tathāgatagarbha. All external material forms, the Six Dusts, are also created by the Tathāgatagarbha. Therefore, when the Tathāgatagarbha transmits the external Six Dusts through the external faculties into the internal faculties, forming the internal Six Dusts, this too is the work of the Tathāgatagarbha.

The internal Six Dusts are composed of subtle Four Great Elements and are also produced by the Tathāgatagarbha, generated from the seeds of the Four Great Elements. Both external dust and internal dust are accumulations of the seeds of the Four Great Elements. However, there is a distinction in the seeds of the Four Great Elements: external dust is the fundamental realm, composed of substantial seeds of the Four Great Elements, while internal dust is not the fundamental realm. It is an illusion conjured based on the external dust, a shadow composed of even more subtle seeds of the Four Great Elements, with a slightly different structure, hence called a shadow. It is like a mirror: the object outside the mirror is a real object, called external dust, while what is inside the mirror is not real matter, thus called a shadow, even though it is also composed of the Four Great Elements. This can be a bit difficult to understand. The shadow and the external form have the same shape but are different in nature; there is a distinction.