妙法蓮華經玄義 2.175

2.175

Third, judging the coarse and the subtle: The two truths of substantial existence are the half-letter teaching, which leads persons of dull faculties to sweep away the dung of frivolous discourse; the meaning of the two truths is not established, so this dharma is coarse. The two truths of illusory [existence] are the full-letter teaching, which instructs those of sharp faculties in the true aspect of all dharmas, attained in common by the three persons; compared to the previous it is subtle, but in seeing only emptiness in common, compared to the subsequent it is coarse. Using the distinctive to enter the shared, one can see the non-empty, which is subtle; but the teaching's discussion of principle is not interfused, and therefore it is coarse. Using the perfect to enter the shared is subtle, and this subtlety is no different from the subsequent; but it carries the expedients of the shared, and therefore it is coarse. The distinctive two truths do not carry the expedients of the shared, and are therefore subtle; but the teaching's discussion of principle is not interfused, and therefore it is coarse. The perfect entering the distinctive is subtle because its principle is interfused; but it carries the expedients of the distinctive, and is therefore coarse. Only the two truths of the perfect teaching are directly the unsurpassed path, and are therefore subtle.