Kena Upanishad

      That which thinks not by the mind, that by which the mind is thought, know That to be the Brahman and not this which men follow after here. -p5

      ...So also Mind does not know That which is behind it, That knows Mind; and it is only when the being involved in Mind can deliver out of its appearances his true Self that he can become That, know it as himself and by it know also Mind in its reality to that which is more real than Mind. ... For given that there is a more real existence than the mental existence, a greater life than the physical life, it follows that the lower life with its forms and enjoyments which are all that men here ordinarily worship and pursue, can no longer be an object of desire for the awakened spirit. -p20