Neoplatonism
A philosophical and contemplative tradition built on Plotinus's vision of reality emanating from the One.
Neoplatonism is not typically listed among "contemplative traditions," yet it may be the single most important philosophical influence on Western mysticism. Founded by Plotinus in 3rd century Alexandria, Neoplatonism offered a comprehensive vision of reality as emanation from the One — an ineffable, transcendent source from which all existence flows in descending levels of being, and to which the soul can return through contemplative ascent.
Plotinus's practical teaching was deeply contemplative. The Enneads describe states of mystical union with the One that are strikingly similar to accounts in Eastern traditions — the dissolution of the subject-object distinction, the recognition of one's deepest identity as inseparable from the absolute. His student Porphyry records that Plotinus experienced this union several times during his life.
The tradition's influence is difficult to overstate. Through Pseudo-Dionysius the Areopagite (likely a 5th-century Syrian monk), Neoplatonic ideas entered Christian theology and became the foundation of the apophatic (negative) mystical tradition — knowing God through what God is not. Through Arabic translations, Neoplatonism entered Islamic philosophy and profoundly shaped Sufi metaphysics. Through medieval Jewish thinkers, emanation theory influenced the development of Kabbalah's Sefirot system. Neoplatonism is the hidden river running beneath all three Abrahamic mystical traditions.