This happens in the imagination (Arabic "mutakhayyila"; Greek "phantasia"), a faculty of the mind already described by Aristotle, which al Farabi described as serving the rational part of the soul (Arabic "ʿaql"; Greek "nous"). This faculty of imagination stores sense perceptions ("maḥsūsāt"), disassembles or recombines them, creates figurative or symbolic images ("muḥākāt") of them which then appear in dreams, visualizes present and predicted events in a way different from conscious deliberation ("rawiyya"). This is under the influence, according to Al Farabi, of the active intellect. Theoretical truth can only be received by this faculty in a figurative or symbolic form, because the imagination is a physical capability and can not receive theoretical information in a proper abstract form. This rarely comes in a waking state, but more often in dreams. The lower type of prophecy is the best possible for the imaginative faculty, but the higher type of prophecy requires not only a receptive imagination, but also the condition of an "acquired intellect", where the human "nous" is in "conjunction" with the active intellect in the sense of God. Such a prophet is also a philosopher. When a philosopher-prophet has the necessary leadership qualities, he becomes philosopher-king.