These are the "haft sifat," or seven attributes of God. There is unanimity of opinion as to the number of attributes, but not as regards their nature and the extent of the knowledge concerning them to which men can attain. Thus some say that the knowledge of God is the first thing to acquire; but Imam Shafa'i and the Mutazilites say that a man must first attain to the _idea_ of the knowledge of God. The meaning of the expression "Knowledge of God" is the ascertaining the truth of His existence, and of His positive and privative attributes, as far as the human understanding can enter into these matters. The unity is not a mere numerical unity but absolute, for the number one is the first of a series and implies a second, but God has not a {119} second. He is "singular without anything like Him, separate having no equal;" for, "had there been either in heaven or earth gods beside God, both surely had gone to ruin." (Sura xxi. 22). God is not a substance, for substance has accidents, but God has none: otherwise His nature would be that of "dependent existence." God is without parts, for otherwise he would not exist till all the parts were formed, and His existence would depend on the parts, that is, on something beside Himself. The orthodox strictly prohibit the discussion of minute particulars, for say they, "just as the eye turning to the brightness of the sun finds darkness intervene to prevent all observation, so the understanding finds itself bewildered if it attempts to pry into the nature of God." The Prophet said: "We did not know the reality of the knowledge of Thee;" and to his followers he gave this advice: "Think of God's gifts, not of His nature: certainly you have no power for that." The Khalif Akbar is reported to have said: "to be helpless in the search of knowledge is knowledge and to enquire into the nature of God is Shirk (infidelity)."[104] A moderate acquaintance with Muslim theology shows that neither the injunction of the Prophet nor the warning of the Khalif has been heeded. According to the early Muslims, the Companions and their followers, enquiries into the nature of God and His attributes were not lawful. The Prophet knowing what was good for men, had plainly revealed the way of salvation and had taught them:-- "Say: He is God alone: God the eternal! He begetteth not, and He is not begotten; And there is none like unto Him." (Sura cxii)