I have already told you that nothing exists except God and this universe, and that there is no other evidence for His Existence but this universe in its entirety and in its several parts. Consequently the universe must be examined as it is; the propositions must be derived from those properties of the universe which are clearly perceived, and hence you must know its visible form and its nature. Then only will you find in the universe evidence for the existence of a being not included therein. I have considered it, therefore, necessary to discuss first in a merely colloquial manner, in the next chapter, the totality of existing things, and to confine our remarks to such as have been fully proved and established beyond all doubt. In subsequent chapters I shall treat of the propositions of the Mutakallemim, and describe the method by which they explain the four fundamental principles. In the chapters which will follow, I propose to expound the propositions of the philosophers and the methods applied by them in verifying those principles. In the last place, I shall explain to you the method applied by me in proving those four principles, as I have stated to you. CHAPTER LXXII Know that this Universe, in its entirety, is nothing else but one individual being; that is to say, the outermost heavenly sphere, together with all included therein, is as regards individuality beyond all question a single being like Said and Omar. The variety of its substances—I mean the substances of that sphere and all its component parts—is like the variety of the substances of a human being: just as, e.g., Said is one individual, consisting of various solid substances, such as flesh, bones, sinews, of various humours, and of various spiritual elements; in like manner this sphere in its totality is composed of the celestial orbs, the four elements and their combinations; there is no vacuum whatever therein, but the whole space is filled up with matter. Its centre is occupied by the earth, earth is surrounded by water, air encompasses the water, fire envelopes the air, and this again is enveloped by the fifth substance (quintessence). These substances form numerous spheres, one being enclosed within another so that no intermediate empty space, no vacuum, is left. One sphere surrounds and closely joins the other. All the spheres revolve with constant uniformity, without acceleration or retardation; that is to say, each sphere retains its individual nature as regards its velocity and the peculiarity of its motion; it does not move at one time quicker, at another slower. Compared with each other, however, some of the spheres move with less, others with greater velocity. The outermost, all-encompassing sphere, revolves with the greatest speed; it completes its revolution in one day, and causes everything to participate in its motion, just as every particle of a thing moves when the entire body is in motion; for existing beings stand in the same