Neoplatonism

Neoplatonism is the philosophical tradition that synthesized Plato's thought into a comprehensive metaphysical system and became the dominant philosophical framework of late antiquity. More importantly, it became the philosophical language through which the mystical experience has been articulated in the West, influencing Christian theology, Islamic Sufism, Jewish Kabbalah, and the Renaissance.

Plotinus (204–270 CE) is the central figure. Born in Egypt, educated in Alexandria, he taught in Rome and produced the Enneads, one of the most extraordinary works of mystical philosophy in any tradition. His system is built on three principles: the One (utterly beyond being and thought), Nous (divine mind, the first emanation), and Soul (which produces the material world). All of reality emanates from the One and yearns to return to it.

The One of Plotinus is not a God who commands or rewards or punishes. It is the ground of all existence, so absolutely prior to all categories that even existence and being are too limited to apply to it. This is the same apophatic approach as the Taoist the Tao that can be named is not the eternal Tao, the Kabbalistic Ein Sof, the Buddhist Sunyata as ultimate ground.

Plotinus's account of mystical union, the flight of the alone to the Alone, describes the experience of the individual soul shedding its separateness and recognizing its identity with the One. He claims to have had this experience four times. His puzzlement upon returning to ordinary consciousness, how did I come down from that?, is the universal mystical grief that Rumi encodes in the song of the reed cut from the reed bed.