Accidents and Existence in Avicenna's Metaphysics of the Healing, III

Avicenna's Metaphysics of the Healing (MotH), as we have seen, gives consideration to the subject, principles, and purpose of the science of metaphysics in the opening book of the treatise. Book two goes on to consider the first of the two divisions of the subject of metaphysics which is the existent/being (ens) inasmuch as it is an existent/being (ens). This first division is substance and he treats it according to his metaphysical principles drawn up in Bk.I. 5-8. We have now arrived at book three where Avicenna begins to treat the other side of the division, namely, accidents.

Book III. 1 is subtitled: "On indicating what ought to be investigated regarding the state of the nine categories and about their accidental [nature]"

He begins book three with a summation of book two's resolutions. "We have clearly [indicated] the quiddity of substance and have shown that it is predicable of the separable, of body, of matter and of form." If we recall Bk I. 5 (esp. (9)-(10)) Avicenna lays out his metaphysical conceptual theses, of which there are initially three 1. existent (ens), 2. thing (res) or quiddity, and 3. necessary. Following this enumeration a fourth arises, namely, 4. existence (esse) which is affirmative aspect of a thing. Here, in book III, we can see Avicenna not only employing these theses but also within the framework of an Aristotelian science. In Book II. ch. 1-2 of the Posterior Analytics Aristotle says that there are four questions we ask of a subject or things. "The kinds of things we inquire about are equal in number to those we know (επιστήμη or scientia), and they are four: (1) a fact, (2) the reason for a fact, (3) if an object exists, (4) what a thing is." (Post. Anal. II. 1. 89b21-25 )

Avicenna is framing his summation in this context and he believes that he has resolved question (4) because he has "clearly indicated the quiddity of substance[...]." He goes on to suggest, with some repetition of earlier comments, that he has also dealt sufficiently with substance and question (3). He says, "regarding body, there is no need to establish [its existence as a substance.] Regarding matter and form, we have already established [the existence of both {in MotH Bk. II}.] As for the separable, we have established its [substantial existence] in the potential [manner] that is close to act, and we will be establishing it [further] hereafter." He also mentions if one remembers what was earlier spoken of soul the existence of separable other than body should be clear.

Hence, he suggests that it is appropriate to move on now to consider and establish the existence of accidents. Remaining in the same framework of the Posterior Analytic Avicenna has two primary questions in mind, is it? and what is it? He begins paragraph (2) answering the latter, "Regarding the ten categories, you have come to understand their quiddities in the introduction to the Logic." So the question "what is it?" of the nine categories or predicamentals has alreadly been resolved in Avicenna's mind with his earlier treatment of them in his Logic. But what about the second question not yet answered, what about their existence?

Avicenna is thinking not simply in the manner of Aristotle here, but is applying his own metaphysical principles, which are similar to Aristotle's, to topics which are also similar to Aristotle's but in numerous and interesting ways they innovations from the Stagirite's own treatments. Considering the existence of accidents Avicenna immediately focuses on "relation."
"Doubtlessly, the relative [...] is something that necessarily occurs [as an accident] to a thing." Relation, he takes as that which is doubtlessly an accident, since it by nature is in another (in alio); it cannot be understood or taken as a relation without another in which its existences depends on. Here, relation is fundamental for Avicenna because establishing the existence of relation as an accident is sufficient to establish all the other categorical accidents that depend on relation, such as action, passion, when, where, position, and possession. That these latter exist as accidents is established by relation's existence as an accident, for what are these latter predicables other than distinct relatives of some kind. (e.g. where is at least a thing relative to place) He concludes accordingly that, "these are states that occur [as accidents] to things in which they inhere as an existent in a subject." (MotH, Bk III. 1 (2))

But there are two accidents that remain, whose existence is not yet established, namely, quantity and quality. With these two the matter is not so simple. This is because some have held various quantities or qualities to be substance or even existent itself, or that all is reducible to one of them. (III. 1. (3)). Avicenna briefly summarizes some of their positions and proposes what must be considered regarding them to show that they are in fact accidents existing in a substance and not substances themselves. This is the focus of chapters 2-9 of book III, first considering the one and quantity and then quality. Finally chapter ten closes book III on the relative.