 In one of his best-known introductory works, Enumeration of the Sciences (Iḥṣā’ al-Ulūm), al-Fārābī (ES: 87) explains that the eighth part of the science of physics is devoted to what is common to the different kinds of animals, namely, the soul, and is studied in Aristotle’s Book of Animals and in On the Soul. Al-Fārābī describes the soul as Aristotle did in On the Soul 2.1, 412a19, that is, as the form or actualization (ἐντελέχεια / antalāshiyā or at-tamām) of a natural organic body that potentially has  life.[1]  Living beings have different faculties: the nutritive, sensitive, appetitive, and rational faculties. The presence of these capacities in living beings is due to the different kinds of soul. The origin of these souls and their capacities is explained by al-Fārābī from a metaphysical, cosmological, and biological perspective.