二諦義 1.25

1.25

問：不依四悉檀說法，用四悉檀何為？解云：二諦是所依，依二諦說四悉檀法。此亦兩種，各取一義明。實而說義名四悉檀，說而實義稱二諦。此即依於二諦方便屬緣不同，是故有四種悉檀也。

Question: If they do not expound the Dharma based on the four siddhāntas, what is the purpose of using the four siddhāntas? It is explained: The two truths are the basis; based on the two truths, they expound the teaching of the four siddhāntas. Here too there are two perspectives, each adopting one meaning to clarify [the matter]: expounding while being real is termed the "four siddhāntas"; being real while expounding is called the "two truths." That is to say, based on the two truths, because skillful means adapt to different conditions, there are four kinds of siddhāntas.