The Buddha Tathāgatas Do Not Preach the Dharma in Vain

Next I will classify [these categories] into crude and subtle all together [as in a bundle]. The first two teachings [Tripiṭaka and Shared], though they contain the aspect of “according to wisdom,” specialize in “according to feelings.” Since they teach with words in accordance with the minds of others, they are called “crude.” As for “advancing from the Shared to the Distinct,” though this contains the aspect of “according to feelings,” it specializes in mixing “according to feelings and wisdom” and teaching both with words in accordance with the mind of others and [the Buddha’s] own. Therefore it is both crude and subtle. The perfect two truths, though it has the aspect of “[preaching] according to feelings,” and so forth, specializes in “[preaching] according to wisdom” and teaches words in accordance with [the Buddha’s] own mind . Therefore it is subtle.

Question: if the first two [types of] two truths specialize in “[preaching] according to feelings,” then they should not be considered an insight into truth nor an attainment of the Path.

Answer: Since it is not an attainment of the Middle Path it is called “[preaching] in accordance with feelings.” The Buddha Tathāgatas do not preach the dharma in vain. Though it is not the supreme siddhānta of the Middle Path it is not lacking in the benefits of the other three siddhānta. Generally speaking these are all classified as belonging to “according to feeling” and thus are crude.

Foundations of T'ien T'ai Philosophy, p 247