the latent power in man and arouse it to activity, and the acquired intelligence or 'aql mustafad is the intelligence aroused to activity and developed under the inspiration of the agent intelligence. Thus the intelligence in action is related to the potential intellect as form is to matter, but the agent intelligence enters from outside, and by its operation the intelligence receives new powers, so that its highest activity is "acquired."
Al-Farabi appears throughout as a devout Muslim, and evidently does not appreciate the bearing of the Aristotelian psychology on the doctrine of the Qur'an. The earlier belief of Islam, as of most religions, was a heritage from primitive animism, which regarded life as due to the presence of a perfectly substantial, though invisible, thing called the soul: a thing is alive so long as the soul is present, it dies when the soul goes away. In the earlier forms of animism this is the explanation of all movement: the flying arrow has a "soul" in it so long as it moves, it ceases to move when this soul goes away or desires to rest. This involves no belief in the immortality of the soul, nor is the soul invested with any distinct personality, all that comes later; it is simply that life is regarded as a kind of substance, very light and impalpable but perfectly self-existent. What may be described as the "ghost" theory marks a later stage of evolution, when the departed soul is believed to retain a distinct
