The creed of Islam "there is no divinity other than God and Muhammad is his prophet" summarizes in its simplicity the basic attitude and spirit of Islam. To grasp the essence of Islam, it is enough to recognize that God is one, and that the Prophet, who is the vehicle of revelation and the symbol of all creation, was sent by him. This simplicity of the Islamic revelation further implies a type of religious structure different in many ways from that of Christianity. There is no priesthood as such in Islam. Each Muslim being a "priest" is himself capable of fulfilling all the religious functions of his family and, if necessary, of his community; and the role of the imam, as understood in either Sunni or Shia Islam, does not in any way diminish the sacerdotal function of each believer. The orthodoxy based on this creed is intangible, and therefore not so closely bound to specific formulations of dogmatic theology as in Christianity. There have been, to be sure, sectional fanaticism and even persecution, carried on either by rulers or by exoteric theologians, against such figures as al-Hallaj and Suhrawardi. Yet the larger orthodoxy, based on the essential doctrine of unity, has always prevailed and has been able to absorb within the structure of Islam all that is not contradictory to the Muslim creed.

In its universal sense, Islam may be said to have three levels of meaning. All beings in the universe, to begin with, are Muslim, i.e., "surrendered to the Divine Will." (A flower cannot help being a flower; a diamond cannot do other than sparkle. God has made them so; it is theirs to obey.) Secondly, all men who accept with their will the sacred law of the revelation are Muslim in that they surrender their will to that law. When 'Uqbah, the Muslim conqueror of North Africa, took leave of his family and mounted his horse for the great adventure which was to lead him through two thousand miles of conquest to the Moroccan shores of the Atlantic, he cried out: "And now, God, take my soul." We can hardly imagine Alexander the Great having such thoughts as he set out eastward to Persia. Yet, as conquerors, the two men were to achieve comparable feats; the "passivity" of 'Uqbah with respect to the Divine Will was to be transmuted into irresistible action in this world.

Finally, we have the level of pure knowledge and understanding. It is that of the contemplative, the gnostic ('arif), the level that has been recognized throughout Islamic history as the highest and most comprehensive. The gnostic is Muslim in that his whole being is surrendered to God; he has no separate individual existence of his own. He is like the birds and the flowers in his yielding to the Creator; like them, like all the other elements of the cosmos, he reflects the Divine Intellect to his own degree. He reflects it actively, however, they passively; his participation is a conscious one. Thus "knowledge" and "science" are defined as basically different from mere curiosity and even from analytical speculation. The gnostic is from this point of view "one with Nature"; he understands it "from the inside," he has become in fact the channel of grace for the universe. His islam and the islam of Nature are now counterparts.

The intellective function, so defined, may be difficult for Westerners to grasp. Were it not for the fact that most of the great scientists and mathematicians of Islam operated within this matrix, it might seem so far removed as to be irrelevant to this study. Yet, it is closer in fact to the Western tradition than most modern readers are likely to realize. It is certainly very close to the contemplative strain of the Christian Middle Ages, a strain once more evoked in part, during the modern era, by the German school of Naturphilosophie and by the Romantics, who strove for "communion" with Nature. Let us not be misled by words, however. The opening of the Romantic's soul to Nature, even Keats's "negative capability" of receiving its imprint, is far more a matter of sentiment (or, as they loved to call it then, "sensibility") than of true contemplation, for the truly contemplative attitude is based on "intellection."