The gods of the lower world were the cosmic forces, planetary influences, the conditions which were destined, the spirits, the powers that held in their hands the rein of the destiny. Orpheus in Arabic means "the knower," "the one who has the knowledge of life." In Arabic the knowledge of life is called "Arifat," and the knower is called "Arif." This also shows us that the real knowledge is the knowledge of sound, the knowledge of rhythm, the knowledge of word and of note. It is this knowledge which gives mastery in the higher or mystical or psychological music. As Wagner says, "Who has the knowledge of sound knows everything." Orpheus pleased the gods of the lower world, and they gave him the promise, "Eurydice will follow you, she follows you. The condition is that you will not look back."