 Essentially, al-Farabi applies Aristotle’s notion of ergon to the cosmos and each of its members. Accordingly, the cosmos as such is not only determined by a certain order, it actually represents the best of all possible structures, as it is the effect of the over-perfect first  cause.[18]  Consequently, every part of the cosmos possesses a specific function which it must perform in order to keep the perpetuum mobile cosmos running smoothly, without interruptions and disturbances. While everything else executes its function by nature, human beings, equipped with reason and free will, must choose to do so. Therefore, they must understand the cosmic order and their own place and duty, or rather ergon, in the frame of this all-embracing structure, which, once again, underscores the significance attached to knowledge in al-Farabi’s thought.