[T]he “Ten Suchnesses” … form one of the Buddha’s best known teachings. Reality in the “reality of all things” means “substance” or “existence.” According to this teaching, the true nature of existence (the reality of all things) can be seen in nine aspects as such: (1) their objective appearances (attributes), (2) their subjective natures (inner natures), (3) their entities (forms), (4) their powers (inner potentials), (5) their functions and activities, (6) their primary or direct causes, (7) their environmental causes (indirect causes), (8) their effects upon others, and (9) their rewards and retributions upon themselves.

This is not a classification of existence, but an illustration of various viewpoints from which the true nature of existence may be understood. The viewer is the Buddha, these nine factors essentially make up a whole as a manifestation of his wisdom. From the first factor (appearances) through to the last (rewards and retributions), all are unified as one. Each is ultimately equal to the others, and so really only one “as such” exists. This one, the tenth factor, is called the “equality of the nine factors.’