English transliteration of the Latin quidditas, meaning "whatness"; in scholastic usage it designates a thing's essence taken precisely in its capacity to inform the intellect of the answer to the question "what is it?"
Related Terms. At most a virtual minor distinction obtains between essence and quiddity: essence is the thing as capacity for existence, whereas quiddity is the thing as capacity to instruct the intellect. The quiddity of a thing, if definable, is analytically expressed in its real definition by its genus and specific difference. As such it is similar to, but more exact than, nature in boethius's first sense: "anything that can be grasped (by the intellect) in any way whatever" (De persona et duabus naturis 1; Patrologia Latina, 64:1341BC). Nature, in the more etymological and Aristotelian sense, is closer to essence than to quiddity inasmuch as nature signifies a thing's principle of operation—effective only through existence.
Such are the comparisons between these terms suggested by St. thomas aquinas (De ente 1, 3). To these he adds form and Aristotle's phrase "the what was to be" (τò τί [symbol omitted]ν ε[symbol omitted]ναι, quod quid erat esse ). He defines the form that is convertible with essence and quiddity as "the complete essential determination" of a thing. This is the "form of the whole" (forma totius, ε[symbol omitted]δος) according to the Avicennian interpretation of book seven of the Metaphysics —an interpretation rejected by Averroës but accepted by St. Thomas (In 7 meta. 9. 1467–69). Form in this sense includes the matter as universalizable as well as the "form of the part" (forma partis, μορφή), the substantial form as distinct from matter (see matter and form). Form thus expresses the completeness of an essence's specification in itself with respect both to existence and to intellect, and in the latter respect is synonymous with quiddity. Some modern scholars concur independently in the Averroist interpretation that Aristotle excludes matter altogether from the notion of form or species and its equivalent, "the what was to be." But St. Thomas insists that Aristotle holds its inclusion necessary in the case of natural substances, since it must be included universally in their definition (In 7 meta. 9.1468; In I anim. 1.24–29).
Aristotelian Meaning. The term quidditas, coined in the 12th century in translations of Avicenna into Latin and possibly also in paraphrasing the Topics, stems ultimately from Aristotle's own phrase "the what was to be." From its grammar and from the probable places of its earliest appearance (Topica 101b 22, 132a 1), it originated in a context of dialectics and predication and was designed as a verbal sort of variable representing the full answer to any Socratic question as to what a thing is, for example, man, virtue, the Sophist, etc. The particular reference of the phrase can be specified in any context by adding a dative, for example, "the what was it for a man to be," or "the being characteristic of man." This full answer, Aristotle says, is expressed in the definition of the thing in question.
As such the phrase must be distinguished from another Aristotelian one, "the what is it" (τò τί ἐστι, quod quid est ), of wider range, since it not only may refer to the complete formula or definition but may also be satisfied by any one of its parts taken separately—genus, matter, difference, or form. Grammatically, the past tense, "was" ([symbol omitted]ν, erat ), has a habitual or transtemporal sense, indicating the specifying, or formal, identity of the essence with respect to any individual of that essence at any time (Meta. 1031a 15–32a 11, esp. 32a 5; Aquinas, In 7 meta. 5) or, in the case of the separate substances, beyond time. Accordingly, in virtue of the "what" element the phrase has formally a noetic reference, whereas in virtue of the verbal elements "was" and "to be" it has a basic ontological connotation. Because of it's ontological reference, the phrase "the what was to be" is superior to the term quiddity. Among the Christian Aristotelians, who departed from Aristotle on the eternity of the world, this transtemporal character of essences is taken to refer to their self-identity as essences—including their openness to identity with their individuals, when the latter exist—or also to refer to their eternal presence as ideas to the divine mind.
Because it can refer also, by the habitual tense ([symbol omitted]ν, "was"), to separate substances, including God, of which St. Thomas says one knows what they are not rather than what they are (De anim. 16), the Greek phrase and the Latin term coined from it do not necessarily suggest that the truly adequate answer to the implied question of "what" must be rational, analytical and complex, after the fashion of a definition. It may be purely intellectual and intuitive. "It is not of the notion of quiddity that it be composite, for then a simple nature would never be found—which is false at least in the case of God—nor is it of its notion that it be simple, since certain composites are found, such as human nature" (In 2 sent. 3.1.1). Quiddity can thus apply to God and the separate substances, which are undefinable by reason of their simplicity and not in virtue of any defect of unity.
Substituting the term quiddity for the more cumbersome "the what was to be," one finds that in Meta. 1029b 14, speaking terminologically, Aristotle defines "the quiddity of each thing" as "that which it is said to be in virtue of itself" (καθ' α[symbol omitted]τό). Excluding things that are only one by accident, such as "white man" or "musical man" and hence indefinable by defect of unity, he says analogically that "quiddity will belong … primarily and in the simple sense to substance, and in a secondary way to the other categories also—not quiddity in the simple sense, but the quiddity of a quality or of a quantity" (1030a 29–32). Finally he seems even to allow a definition, in an improper sense, of "white man" as an accidental whole, "but not in the sense in which there is a definition either of white or of substance" (b 13); however, he does not allow the notion of quiddity this improper range.
Modern Relevance. The insistence of G. W. F. hegel on the impossibility of philosophically discussing anything in a purely ontological way apart from its relation to mind should be reappraised in view of the convertibility of quiddity and essence and of truth and being (see transcendentals). At the same time, a realistic philosophy must maintain the absolute primacy of being and essence and also their inseparable transcendental relevance, as truth and quiddity, to intelligence on all levels, and first of all to the divine mind. In this connection, the socalled "presuppositionless method" of phenomenology, as proposed by E. husserl, that would suspend judgment on the question of existence and real being, itself makes a supposition inasmuch as it presumes that essence can speak to mind without revealing itself as, first and radically, capacity for existence. Expressed in the above outlined language, this method appears to be an attempt to treat essence as quiddity rather than as essence. The work of the medieval disciples of St. Thomas and of John duns scotus on these questions should be brought into dialectical confrontation with the analogous work of modern epistemologists and phenomenologists. Particularly worthy of mention are the Quaestiones disputatae de esse intelligibili of william of alnwick (see History of Christian Philosophy, 468, 768–769).
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[j. j. glanville]