What do “character, nature, substance, potential … and essential unity” actually mean? … Zhanran, Zhiyi’s later disciple, explains that these ten can be grouped in three modalities — form, mind, and causality — that characterize all existents. “Character,” which could also be translated as “mark,” “sign, or “aspect,” is what can be seen externally; in the case of a person, it denotes one’s outer appearance. “Nature” is internal, what belongs to that person intrinsically. “Substance” denotes the union of these two as a particular individual; each existent, in Tendai thought, has both physical and mental aspects. “Potential” is the capacity for action, while “function” is the exertion or display of that potential. These two suchnesses thus pertain to space. “Cause, condition, result, [and] effect” refer to the dimension of causality, and therefore, time. “Causes” are volitional acts, or karma. “Conditions” are the circumstances that condition actions. “Result” is the potential karmic consequence inherent in a volitional act, and “effect” is its eventual manifestation. All ten are “essentially unified,” or ultimately consistent. For example, the character, nature, function, causes, and results of a denizen of hell will reflect and perpetuate misery; those of a bodhisattva will express insight and compassion.