The feature of both explainable and unexplainable is related to the length of function. On the one hand, the length of function refers to the Buddha’s soteriological activity of saving beings, beginning from an incalculable past in the Origin until the more recent event of teaching the Lotus Sūtra in the Traces. On the other hand, for different capacities of beings, the Buddha expounds either the truth that can be conceptually understood, i.e., explainable, or the truth that is beyond conceptualization, i.e., unexplainable. The feature of neither explainable nor unexplainable denotes the inconceivability of the four truths, since the Ultimate Truth they contain cannot be conceptually conceived. In view of the inadequacy of language and of conceptual thoughts in conceiving the Ultimate Truth, the four truths cannot be defined by terms such as superior or vast, long or short, and sameness or difference. This is an integrated reality that everything is without difference and is subtle. (Vol. 2, Page 105)