Hakan Genc

*I am turning this dissertation into a monograph. Please contact me if you will cite it. Comments and questions are welcome!* Abstract: This dissertation discusses al-Fārābī’s views on unity presented in his Kitāb al-wāḥid wa-l-waḥda (Book of the One and Unity) (henceforth KW) by explaining them along with al-Fārābī’s wider metaphysical project and the earlier philosophical works that informed al-Fārābī’s views on unity. Al-Fārābī’s discussion of the senses of unity and multiplicity in KW has its origin primarily in Aristotle’s discussion of unity and multiplicity in Metaphysics Δ.6, but there are some major differences between al-Fārābī’s discussion of unity and multiplicity in his KW and Aristotle’s corresponding discussion in the Metaphysics. This dissertation spells out two of these major differences. This dissertation has three chapters. In Chapter 1, I place KW in the context of al-Fārābī’s wider metaphysical project. I review al-Fārābī’s accounts of the subject-matter of metaphysics as a demonstrative science, and I explain how al-Fārābī implemented his understanding of what metaphysics deals with in a number of metaphysical works including KW. In Chapters 2 and 3, I explain the two major differences between al-Fārābī and Aristotle. In Chapter 2, I explain how and why al-Fārābī significantly changed Aristotle’s account of the one in number (hen arithmō(i) / kat’ arithmon = wāḥid bi-l-ʿadad). Unlike Aristotle, al-Fārābī explicitly distinguishes the senses of unity used in many-place contexts and those used in one-place contexts; for example, when we say that the point is one because it is not quantitatively divided, we use “one” in a one-place context, signifying a property of the point; on the other hand, when we say that Zayd and ʿAmr are one in species because they have the same species, we use “one” in a many-place context, signifying a relation between Zayd and ʿAmr. Al-Fārābī articulates his idea of unity in number so that it grounds all the senses of unity used in many-place contexts. His direct source for articulating his idea of unity in number is not Aristotle’s discussion of the one in number in the Metaphysics but it is Aristotle’s discussion of (the one and) the same in number in Topics I.7. In Chapter 3, I discuss the second major difference between al-Fārābī and Aristotle. Al-Fārābī’s senses of unity by virtue of circumscription (inḥiyāz) (by a place (makān) or by an extremity (nihāya) or by a quiddity (māhiyya)) do not have precedents in Aristotle. To put it briefly, X is said to be one by virtue of circumscription by Y because X has Y and nothing else in the relevant class has Y. So, Y ‘unifies’ X by containing it and separating it from other things. In this chapter, I clarify what al-Fārābī means when he talks about circumscription in general and circumscription by a quiddity in particular. Then, I discuss some texts from late antique Greek philosophers that likely provided starting points or confirmations for al-Fārābī’s ideas of unity by virtue of circumscription. Finally, I suggest that al-Fārābī’s motivation for developing this sense of unity and extending the idea of circumscription to the corresponding sense of being by virtue of circumscription by an extramental quiddity was to make better sense of the argument for the equivalence between being and unity that Aristotle presents in Metaphysics Γ.2 and Iota 2. In addition to several topical appendices, this dissertation contains an English translation of KW as an appendix.

Al-Fārābī’s discussion of the senses of unity in Kitab al-Wāḥid wa-l-Waḥda (Book of the One and Unity) (henceforth KW) has its origin mainly in Aristotle’s discussion of the senses of unity and multiplicity in Metaphysics Delta 6 and Iota, but there are some major differences between al-Fārābī’s discussion of unity and multiplicity in his KW, and Aristotle’s corresponding discussion in the Metaphysics. This paper explains one of these major differences, namely al-Fārābī’s treatment of the sense of unity in number (al-waḥda bi-l-ʿadad). I try to show that unlike Aristotle, al-Fārābī is interested in explicitly distinguishing the senses of unity that are used in one-place contexts (monadic) from those which are used in many-place contexts (polyadic), and that al-Fārābī articulates his sense of unity in number with the features needed for it to perform a special function of grounding all the senses of unity used in many-place contexts. In other words, to put it roughly, two things, X and Y, are said to be one because something about them, Z, is one in number. For example, Zayd and ʿAmr are one in species, which is one of the senses of unity used in many-place contexts, and they are one in species because their species, the human kind, is one in number. I spell out the features with which al-Fārābī articulates his sense of unity in number for it to perform this function of grounding all the senses of unity used in many-place contexts. Finally, I argue that al-Fārābī develops his sense of unity in number with these features not from Aristotle’s discussion and use of unity in number in the Metaphysics primarily, but rather, al-Fārābī’s primary source is Aristotle’s discussion of sameness in number in Topics I.7.