In the Sixth Discourse of the Asrar Nameh, Farid al-Din Attar employs the metaphor of the ocean and its foam to distinguish between Ultimate Reality and the phenomenal world. He instructs the spiritual seeker to 'see the ocean' (Divine Reality) and recognize that the physical universe is merely illusory 'foam' (kefk) resting upon its surface. Attar emphasizes that the material world is a fleeting illusion (khiyal) and compares those engrossed in worldly forms to children at play, while the spiritually mature look past these illusions to perceive the underlying Divine Unity.