Page:Arabic Thought and Its Place in History.djvu/190

 or rest; and others, again, are such as the faculties possessed by the non-rational souls of the spheres, which produce movement directly without external impulse. No force is infinite; it may be increased or diminished, and always produces a finite result.

Time is regarded as essentially dependent on movement; although it is not itself a form of movement, so far as the idea of time is concerned, it is measured and made known by the movements of the heavenly bodies. Following al-Kindi place is defined as "the limit of the container which touches the contained." Vacuum is "only a name", in fact it is impossible, for all space can be increased, diminished, or divided into parts, and so must contain something capable of increase, etc.

God alone is "necessary being," and so the supreme reality. Space, time, etc., belong to "actual being," and whatever necessity they possess is derived from God. The objects studied in physical science are only "possible being," which may or may not become "actual being." God alone is necessarily existent through all eternity: He is the truth in the sense that He alone is true absolutely, all other reality is so only in so far as it is derived from God. From God by emanation comes the  ' aql or "Agent Intellect," and from this proceeds the intellect or reason which differentiates the rational soul in man from the soul in other creatures. To every man this intellect is given, and in due course it returns to the "Agent Intellect" which was its source. The soul's possible