It is to the Spirit or Mind that the higher reality and all activity belong, and matter has to dispose itself in conformity with the desire of the Spirit. Midway between the Spirit of God and the material and bodily world stands the Soul, and it is the Soul which first called into being the world of the Spheres. From this Soul of the world the Human Soul is an emanation. In its nature, that is, in its operations, it is bound to the body with which it is united, but in its spiritual essence it is independent of the body; and thus the influences of the stars, which are limited to physical occurrences, do not affect it. Kindi goes on to say that our Soul is an uncompounded, imperishable substance, descended from the world of reason into that of the senses, but endowed with a recollection of its earlier condition. It does not feel at home here, for it has many needs, the satisfaction of which is denied to it, and which consequently are attended with painful emotions. Verily there is nothing constant in this world of coming and going, in which we may be deprived at any moment of what we love. Only in the world of reason is stability to be found. If then we desire to see our wishes fulfilled, and would not be deprived of what is dear to us, we must turn to the eternal blessings of reason, to the fear of God, to science, and to good works. But if we follow merely after material possessions in the belief that we can retain them, we are pursuing an object which does not really exist. 5. Kindi’s theory of knowing corresponds to the ethical and metaphysical duality of the sensible and the spiritual. According to it our knowledge is either knowledge conveyed by the senses, or knowledge acquired by the reason: that which lies between,—the Fancy or Imagination,—is called a mediating faculty. The senses, then, apprehend the Particular, or the material Form, but the reason conceives the Universal,—species and genera, or the spiritual Form. And just as that which is perceived is one with Sense-Perception, so too that which is conceived by the reason is one with Reason itself. Here then emerges for the first time the doctrine of the Reason or of the Spirit or Mind, (νοῦς, ʻaql) in a form in which, merely modified somewhat, it occupies a large space with the later Muslim philosophers. It continued to be a characteristic feature of philosophy in Islam throughout its whole course. And just as in the controversy regarding Universals in the Christian Middle Ages an objective and scientific interest is made evident also, so in the philosophical discussions of the Muslims concerning the thinking Spirit, the subjective requirement of intellectual culture is brought conspicuously to the front.