 Thus Fârâbî’s analyses of the senses of “being” in the Book of Letters, and of the senses of “one” in On the One, give the basis for his account of a “transcendental” sense of “one” in which it is mutually entailing with “being”, and also for his account of how unity and existence are predicated of God (see the next section): once we distinguish the different senses, and understand how they are related, we will see that circumscription by a quiddity is both the strongest sense of existence and the strongest sense of unity. And since every being in every category, individual or universal, is circumscribed by a quiddity, Fârâbî’s analysis allows him to vindicate his claim against Kindî that each of these things is truly one, and indeed essentially one.