Zen personal trouble or crisis. Though Zen-narrative states that it is a "special transmission outside scriptures" which "did not stand upon words", Zen does have a rich doctrinal background, which is firmly grounded in the Buddhist tradition. It was thoroughly influenced by the Chinese understanding of Yogacara and the Buddha-nature doctrine, Zen integrates both Yogacara and Madhyamaka and the influence of Madhyamaka can be discerned in the stress on non-conceptual insight and the paradoxical language of the koans. Most essential are "the most fundamental teaching that we are already originally enlightened", and the Bodhisattva ideal, which supplements insight with Karuṇā, compassion
Doctrinal background of Zen we conceive of is the result of the working of the five skandhas—results of perception, feeling, volition, and discrimination. The five skandhas together compose consciousness. The "things" we are conscious of are "mere concepts", not "Ding an sich". It took Chinese Buddhism several centuries to recognize that sunyata does not refer to "wu", "nothingness", nor does Buddhism postulate an undying soul. The influence of those various doctrinal and textual backgrounds is still discernible in Zen. Zen teachers still refer to Buddha-nature, but the Zen tradition also emphasizes that Buddha-nature "is" sunyata, the absence of an independent and substantial self. In