 Every existent comes to be, according to al-Fārābī, by the First Existent. This takes place through a sort of expansion or emanation through which the First Existent necessarily gives existence to every being in the universe. Yet this does not imply any addition to its own perfection. In the initial emanation, from the First Existent proceed the second intellects. These intellects themselves, through the apprehension of themselves and the First Existent, are in turn the cause of the celestial bodies. In The Political Regime al-Fārābī mentions that the number of second intellects or second causes is identical to the number of celestial spheres from the highest, the first heaven, to the last, namely, the sphere of the moon (al-Fārābī KS: 32; PR: 29). In The Virtuous City he explicitly enumerates nine spheres starting with the first heaven, and then the fixed stars, Saturn, Jupiter, Mars, the sun, Venus, Mercury, and the moon (al-Fārābī VC: 100–105). There is a tenth intellect, namely, the active intellect (‘aql al-fa ‘‘āl), whose activity is very relevant mainly for two reasons: (1) this intellect governs together with the celestial spheres the sublunary world, and is even involved in the processes of generation and corruption (al-Fārābī LI: 29–30; OI:  75);[2]  (2) furthermore, as will be explained in the fourth section, this intellect also provides the first principles of understanding through which human beings can attain happiness (al-Fārābī VC: 204–205).