David Bentley Hart

 "Contemplative and philosophical traditions, Eastern and Western, insist on this: that the source and ground of the mind’s unity is the transcendent reality of unity as such, the simplicity of God, the one ground of both consciousness and being.

 For Plotinus, the oneness of nous, the intellective apex of the self, is a participation in the One, the divine origin of all things and the ground of the openness of mind and world one to another. For Sufi thought, God is the Self of all selves, the One—al-Ahad—who is the sole true 'I' underlying the consciousness of every dependent 'me.'

 According to the Kena Upanishad, Brahman is not that which the mind knows like an object, or that the eye sees or the ear hears, but is that by which the mind comprehends, by which the eye sees, by which the ear hears; atman—the self in its divine depth—is the eye of the eye, the ear of the ear, the ground of all knowing."