二諦義 1.24

1.24

Question: Since the two truths and the four siddhāntas both subsume all phenomena exhaustively, for what reason do all Buddhas expound the Dharma based on the two truths and not based on the four siddhāntas? It is explained: Generically, both are permissible: since they expound based on the two truths, they also expound based on the four siddhāntas. Specifically, they are not parallel. Why? There is a reason for this: [the Buddha] wishes to make clear that all that the Buddhas speak is real. The Vajracchedikā Prajñāpāramitā states: "The Tathāgata is one who speaks the true, one who speaks the real." Therefore, they expound based on the two truths. The designation "four siddhāntas" does not specifically emphasize the real, and therefore they do not expound based on the four siddhāntas.