Perhaps the most concise summary of enlightenment would be: transcending dualism. … Dualism is the conceptual division of the world into categories … human perception is by nature a dualistic phenomenon—which makes the quest for enlightenment an uphill struggle, to say the least.
Chapter 9: "Mumon and Gödel" - Gödel, Escher, Bach: an Eternal Golden Braid (1979)