unification of the three truths ［円融の三諦］ ( en’yū-no-santai): A principle set forth by T’ien-t’ai (538–597) based on the Lotus Sutra. It explains the three truths of non-substantiality, temporary existence, and the Middle Way as an integrated whole, each of the three containing all three within itself. T’ien-t’ai identified this as the view of the three truths revealed in the perfect teaching, or the Lotus Sutra, in contrast to the separation of the three truths, the view espoused in the specific teaching.
Separation of the three truths is the view of the three truths as separate and independent of one another. The truth of non-substantiality means that phenomena have no existence of their own; their true nature is non-substantial. The truth of temporary existence means that, although non-substantial in nature, all phenomena possess a temporary reality that is in constant flux. The truth of the Middle Way means that all phenomena are characterized by both non-substantiality and temporary existence, yet are in essence neither.
The unification of the three truths means that the truths of non-substantiality, temporary existence, and the Middle Way are inherent in all phenomena. T’ien-t’ai taught a form of meditation called the threefold contemplation in a single mind, aimed at grasping the unification of the three truths, eradicating the three categories of illusion, and acquiring the three kinds of wisdom (the wisdom of the two vehicles, the bodhisattva wisdom, and the Buddha wisdom), all at the same time.