불교전통에서 붓다의 일생을 전할 때 빠지지 않고 등장하는 `사문유관(四門遊觀)`은 동, 남, 서, 북이라는 4방위와 그에 상응하는 노병사(老病死)와 출가행(出家行)의 네 가지 목격담으로 정형화(dramaturgy)되어 있다. 하지만 붓다에게 있어서 깨달음을 위한 철학적 방황의 직접적인 단초가 된 사문유관의 일화가 왜 동-남-서-북 4방위의 출유(出遊)로 정형화된 것인지 딱히 그 이유를 찾기가 쉽지 않다. 본 논문에서는 사문유관에 정형화된 동-남-서-북의 방위구조와 그에 상응하는 [생]노병사와 출가행의 존재론적 도식은 결국 대승불교의 형이상학적 산물로서 정형화된 것임을 고찰하고 있다. 시선축을 중심점이나 수미산에 고정시켜두고 관찰점을 남쪽에 두고 있는 힌두철학의 Sri-Yantra나 불교의 아비달마적 세계의 실유론적 관점과는 달리 사문유관은 붓다의 존재론적 고민과 출가 그리고 견성과 회향의 일생을 동-남-서-북이라는 방위구조에 중층적으로 담아내고 있는데, 이와 같은 사문유관의 방위구조와 도식에 담긴 대승불교의 형이상학적 의미는 5방불 만달라로 대변되는 대승불교의 밀교적 만달라의 색 배치와 방위구조에 나타난 상징성에서도 살펴볼 수 있다.

In the Mahayana Buddhist tradition, the Four-door Encounters(四門遊觀) of Buddha`s life is known as the direct motive of the Siddhartha`s renunciation, which is dramatically standardized in its directional structure of the east-south-west-north with corresponded ontological schema of the [birth and] old age, sickness, death and an ascetic. But we do not know exactly that why the directional structure and ontological schema has corresponded in that way. Thus this paper has speculated about its Mandalic-meanings of the Four-door Encounters. Through the speculations in the paper, we can understand that the directional structure and its ontological schema of the Four-door Encounters is eventually standardized as an episodic product of the Mahayana Buddhism`s metaphysical view. In fact, the Sri-Yantra`s metaphysical view of Hindu philosophy and the Abhidharma`s metaphysical view of the Buddhist philosophy have a Self-concerned(實有) view, which is the view from axis(視線軸) is fixed on the Bindu(中心點) or Mt. Kailash(須彌山), and the view to axis(觀察點) is placed from South direction. However, the metaphysical view of the Four-door Encounters is not fixed on the Bindu or South direction. The metaphysical view of the Four-door`s Encounter has overlapped Mahayana metaphysics as it is figured in its directional structure and ontological schema without the Self-concerned view. The metaphysical view of the Four-door`s Encounter is also well figured in the Mahayana Tantrac Mandala with its color schema and directional structure corresponded with the Mandala of Five Dhyana Buddha(五方[禪定]佛). As the Four-door Encounters has a double-layered structure of the Buddha`s life, which has a solution process of the ontological question and a dedication process of the great Bodhicitta(菩提心). Likewise, the Mandala of Five Dhyana Buddha has a double-layered structure in its color schema and directional structure. It means that the Four-door Encounters and the Mandala of Five Dhyana Buddha are a product of the Mahayana Buddhism`s metaphysical view as a symbolic collection. In the similar context, Lama Anagarika Govinda(1966) also surmises that the first mandala may have been created when the devout transformed the stupas that sheltered the relics of the Buddha by adding a path that was surrounded by a stone railing with four gates. Each of the gates marked one of the four important events in the life of the Buddha. If it were, as the stupas are a starting point of the Mahayana Buddhism, it means that the Buddha`s life is the Mahayana Tantric Mandala itself as a metaphysical symbolic collection.