Page:Arabic Thought and Its Place in History.djvu/160

 reliable judgment, who uses his judgment in an upright way to discern between good and evil, and thus is distinguished from a crafty man who employs his mind in devising evil expedients. Theologians use the term  ' aql to denote the faculty which tests the validity of statements, either approving them as true or rejecting them as false. In the Analytica Aristotle uses "intelligence" for the faculty by which man attains directly to the certain knowledge of axioms and general abstract truths without the need of proof; this faculty al-Farabi explains as being the part of the soul in which intuition exists, and which is thereby able to lay hold of the premises of speculative science, i.e., the reason of intelligence proper as the term is employed in the de anima, the rational soul which Alexander of Aphrodisias takes as an emanation from God. Following al-Kindi, al-Farabi speaks of four faculties or parts of the soul: the potential or latent intelligence, intelligence in action, acquired intelligence, and the agent intelligence. The first is the  ' aql hayyulani, the passive intelligence, the capacity which man has for understanding the essence of material things by abstracting mentally that essence from the various accidents with which it is associated in perception, more or less equivalent to the "common sense" of Aristotle. The intelligence in action or  ' aql bi-l-fi'l is the potential faculty aroused to activity and making this abstraction. The agent intelligence or 'aql fa  al'' is the external power, the emanation from God which is able to awaken