Below Every Tangled Hierarchy Lies An Inviolate Level — Douglas R. Hofstadter

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.

This type of paradox is quite characteristic of Zen. It is an attempt to "break the mind of logic".

Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.