Predicables

PREDICABLES. - The term (Gk. κατηγορούμενα, whence also, in Italian, "categoremes") means "that which can be predicated" of another. In a technical sense in logic, the predicables are the "modes of predicability," that is, the general relations that predicates assume toward subjects. In Aristotelian realism, reality, conceived as an essential degree of being, open, in becoming, to further modes and forms (accidents), grounds a different ontological belonging of its own determinations. The predicables indicate, expressed in general logical relation, the degree and mode of belonging of all possible determinations of reality.

Aristotle (Topics, I, 4 [5]) distinguishes three classes of predicates: genus, property, accident: "πᾶσα δὲ πρότασις... ἢ γένος ἢ ἴδιον ἢ συμβεβηκός δελοί."

The "property" is then split into ἴδιον (not indicative of the essence) and ὄρος (definition, essence, species). The "difference" (διαφορά) is joined by Aristotle in the cited passage to the genus, but elsewhere (Top., IV, ch. 6, 128 a 21 ff.) he affirms its distinction. The explicit classification into five predicables—genus, difference, species, property, accident—is that of Porphyry (Isagoge, ch. 1); the same later became common in scholasticism: "omne quod de pluribus univoce praedicatur, vel est genus, vel species, vel differentia, vel accidens, vel proprium" (C. Gent., I, 32). Its foundation must be recognized in that a predicate either indicates determinately and adequately the specific nature of the subject (ὄρος, species), or expresses it inadequately and indeterminately (γένος, genus), or indicates its distinctive essential note (διαφορά, differentia), or a necessary attribute and therefore derivable from the essence (ἴδιον, proprium), or finally a contingent and variable attribute (συμβεβηκός, accidens; cf. Aristotle, Top., I, 6 [8]). It is clear that the Aristotelian-Porphyrian classification, if phenomenologically it can also be accepted by other schools, as regards its derivation and ontological justification is a function of a substantialist-pluralistic conception of reality. It therefore cannot have essential significance in phenomenalism (v.), where the substantial structure of reality is denied, and in monism (v.), which resolves the multiplicity of beings into a single substance or principle (v.). In Kant the predicables are pure concepts of the understanding derivable immediately from the categories (e.g., "action and passion" from causality: cf. Kritik d. r. Vernunft, Transzend. Anal., I, I, ch. 1, sec. 3, § 10; Ital. trans. by G. Gentile, I, Bari 1940, pp. 113-14).

The genus is "that which is predicated essentially (ἐν τῷ τί ἐστιν) of many things differing in species" (Aristotle, Top., I, 4 [5], 102 a 31). It is therefore an indeterminate essential predicate, such that, although found in all individuals of a class, it extends beyond it, e.g., "animal" said of man. It should be noted that the genus can be taken either in a "precisive" sense, excluding every further specific determination (purely abstract consideration), or in a "potential" sense, without exclusion of its further possible determinations. It is in this second sense that the genus is predicated of the species and the individual: "man is a living being" does not exclude "what" determinate living being he is; rather, in the concreteness of the proposition, it implicitly includes it. Therefore, according to St. Thomas, the genus is predicated not as a part, but as a potential whole, inasmuch as "implicite in sua significatione, quamvis indistincte, totum id quod determinate est in specie dicit" (De ente et essentia, ch. 3; cf. C. Gent., I, 26). Since in the logical structure of reality different essential levels are determinable, the genera in which a subject can be placed are multiple (e.g., man is living, animal, vertebrate, etc.). The "proximate" genus, in relation to a given species, is that which immediately constitutes it. It should be observed in any case that the distinction of metaphysical degrees or levels is rightly held by Thomism (cf. ibid.; In VII Met., lect. 12, n. 1564; Sum. Theol., 1ª, q. 76, a. 3 ad 4) to be purely logical or formal-abstract: from the ontological point of view every nature or degree of being is unity and concreteness, even if, by its real composition, it objectively grounds the noetic fragmentation into a scale of distinct concepts.

The difference is the distinctive essential predicate: it therefore indicates the specifically constitutive and characteristic element of a given nature, e.g., "rationality" in man. The difference is thus, in the proper sense, specific (speciem-faciens, εἰδοποιός; Arist., Top., VI, ch. 6, 143 b 8). Nevertheless in Aristotle the concept is still wavering (cf. ibid., IV, ch. 6; Met., V, 9, 1018 a 12); and moreover even in later logic the distinction of difference into "specific" and "generic" is accepted (the latter not constitutive of the species, inasmuch as it determines a remote genus, e.g., "mortal" said of man). Indeed, with Porphyry, scholasticism accepts the distinction of difference into propriissimam, propriam, communem (the latter purely accidental: cf. Sum. Theol., 1ª-2ª, q. 72, a. 3 c.; In Met., V, lect. 12, n. 916 ff.). The difference within the same species (individual difference) was called by the scholastics "numerical" difference. The term is inexact, inasmuch as every individual realizes a different "perfection" and concretization of the species and is therefore constituted in its individuality by an ontological difference that is not merely quantitative-numerical. It should be noted that "difference" is not the same thing as "diversity"; for, while the latter prescinds from it, difference always implies a commonality in the genus: "Differens omne est diversum sed non convertitur" (St. Thomas, In Met., loc. cit.; cf. Sum. Theol., 1ª, q. 3, a. 8 ad 3 and q. 90, a. 1 ad 3; C. Gent., I, 17).

The species is the complete essential predicate, said of many things differing in number (Porphyry, Isagoge, ch. 2). It therefore expresses the "ontological degree," the "essence," and also the "class" of the subject. Since the specific degree of a being is defined precisely as a determination of the genus, "the species [and therefore the definition] result from the genus and the differences": Ἐκ γὰρ τοῦ γένους καὶ τῶν διαφορῶν τὰ εἴδη (Met., X, 7, 1057 b 7). The relation of the species to the genus (and analogously of the individual to the species) is, according to Aristotle and St. Thomas, a relation of participation (v.; cf. Arist., Topica, IV, 1, 121 a 12 ff.; St. Thomas, In Boeth. De hebdom., lect. 2; C. Gent., I, 32, amplius 2). The derivation from Plato is evident, where εἶδος is the real-ideal form, imitated and participated in by empirical individual reality (v. IDEA). Identified with that of "class," the concept of species loses its ontological content, inasmuch as the "class" can be sufficiently qualified by common and constant characteristics, even if not essential, e.g., sometimes biological species or "classes."

The property indicates a predicate necessarily connected with the specific nature, "causatum ex principiis essentialibus speciei" (St. Thomas, De spiritualibus creat., a. 11, c.; cf. Aristotle, Top., I, 5, 102 a 31), e.g.: "man is capable of expressive articulate language." In a restricted sense, the property is therefore a constant characteristic of an entire species and of that species alone. But already from Porphyry (Isagoge, ch. 4; cf. Aristotle, Top., V, 1) "property" is understood in different senses: that which belongs a) to a single species but not to all of it; b) to an entire species but not only to that one; c) to an entire and only one species but not constantly; d) to an entire species, only to that one, and always (omni, soli, semper). In the physical sciences and in natural history the concept of property is taken promiscuously in one or another of the senses indicated.

The accident is the contingent or variable predicate, that is, "that which can be present and not be present without corruption of the subject" (Porphyry, Isagoge, ch. 5; cf. Aristotle, Top., I, 5 and 9; Met., IV, 30, 1025 a 14, 31), insofar as it "non causatur ex principiis essentialibus speciei, sed accidit individuo" (St. Thomas, De spiritual. creat., a. 11, c.). For the most part, but not necessarily (ibid.; cf. J. Stuart Mill, System of logic, I, I, ch. 7), the accident indicates a character separable from the individual. It should be noted that the predicamental accident is something other than the accident in the metaphysical sense. The latter is defined in relation to substance as a determination (to which it does not belong to subsist in itself) of subsistent being. Even that which from the point of view of predicability or logical belonging is "property" can be, from the metaphysical point of view, an "accident," for example, freedom with respect to spiritual substance. The accident in the metaphysical sense can furthermore assume the determinations of genus and species: cf. the nine supreme genera of the Aristotelian classification of the categories (v.).

The Aristotelian-Scholastic doctrine of the predicables has, as has been said, an objective foundation in experience, which attests the plurality of the degrees of being and the varying ontological immediacy of their determinations. It is not, however, free from limits and uncertainties. There is, for example, a well-founded observation by J. Stuart Mill (v.) that the genus can also be constituted by non-essential notions: for example, the genus "biped" including the biological species "man" (cf. System of logic, I, 7). As for the specific difference, it can vary according to the type of classification intended: for the naturalist, for example, the "difference" of the human species is sought in a different direction from "rationalitas" (in somatic, morphological, physiological characters). The very concept of an "essential" predicate is (already in Aristotle himself) uncertain. It can in fact comprise: a) the fundamental notes of a concept from which all the others derive; b) the notes "necessarily" connected with those; c) the multiple essential relations of that concept. The distinction between what is "essential" or "specific" in the strict sense and what is "property" is therefore not easy. "Essence," "species" sometimes, rather than a concept with a unitary ontological content, is the result of a set of "distinctive characters" or "properties." If, moreover, classification serves well enough for certain fundamental divisions of natural beings (bodies, plants, animals, man), where logical determination proceeds by broad differences, it shows itself inadequate for the more concrete determinations of reality (it is almost impossible to determine the "difference" in mineral and biological species and subspecies). It is equally inadequate for artificial or logical-mental entities ("essence" for artificial objects is an analogical concept, and therefore not every "specific" predicate is always, in the strict sense, essential). Classification finds even more difficult application where it is not a matter of qualifying substances, but facts, activities, phenomena, such as, for example, "movement," "energy," "mass," "electricity," "light," etc. (which have so great a part in the constitution and explanation of material reality), or "instinct," "need," "free act" (fundamental in biological-spiritual reality).

The Aristotelian-Scholastic predicables are therefore to be understood in the sense of a simple logical approximation to the complex structure and articulation of the real.

Ugo Viglino