QUESTION OF UNIVERSALS. - A famous controversy, and at certain moments highly clamorous, concerning a problem which, because it was posed in terms that were not always clear, presented itself progressively as susceptible of opposite solutions.
The first logic of the Greeks was mathematics, which was so called because it appeared to be the "discipline" par excellence, inasmuch as it permits, by means of number and geometric figures, the reduction of the multiplicity of experience to unity — what seemed always varied and different under the dominion of an immutable law, what was sensory impression, to science. And the concepts of mathematics were ordered by genera and species into a compact system that permitted the most rigorous deduction, and this was transferred into physical reality together with number, considered the essence of things. To defeat the sensualism and consequent relativism of the Sophists, Socrates inaugurated the search for the universal concept in the treatment of moral problems (Aristotle, Met., I, c. 6, 987 b 1-4). Plato transferred the method of this search to nature in general, universalizing qualities on the model of numbers and geometric figures, which are abstract quantitative schemata, without heeding that physical qualities, when schematized, become unreal abstractions, such as animality, horse-ness, etc. The Platonic ideas are, for the most part, abstractions of empirical qualities, which usurp the fixity (necessity, eternity, universality) of numbers and figures. And just as the Pythagoreans had made number the "essence" of things, so for Plato the ideas are the eternal and universal essence of the mutable and contingent things that appear in space and time. Placed above space and time, they are in themselves and for themselves, beyond the heaven that is the limit of all mutability, and have therefore a hyperuranian nature, articulating themselves into a system of dialectical relations around the idea of the Good, from which they are radiated. Aristotle did not deny the Platonic ideas, but criticized their separation from the sensible world, showing that the separated idea can be neither essence nor cause of things, nor principle of their knowability; and he strove to reunite what Plato had separated, bringing the idea back to act that determines and organizes matter, as intelligible principle of unity and distinction and as form inherent in things themselves (εἶδος ἔνυλον: Met., VII, c. 11, 1037ᵃ, 29).
Plato, as is well known, had long labored to resolve the problem of the relation to be established between the separated idea and the things of the sensible world, and, after having thought of a relation of μίμησις and of μέθεξις, had settled on the relation of κοινωνία, envisaging the possibility that one and the same essence, in itself one and separate, could be communicated, not by parts, but whole and entire, to particular things, without losing its unity, so that it could be called "one over many" and "one in many" (cf. Parmen., cc. 5-6, 131ᵃ-133ᵃ). To this manner of participation Aristotle too had clung. Except that the form inherent in things acquires, on contact with matter, an individual mode of being, and loses its Platonic universality. To save this universality, without which there can be no science, Aristotle devised the doctrine of abstraction and of the agent intellect. In particular things the universal is only in potency; but freed from contact with matter, it is universal in act, thanks to the action of the agent intellect which abstracts it from particulars. Therefore he could affirm that "the universal animal is either nothing, or posterior" to particular animals (De anima, I, c. 1, 402ᵇ, 5-8).
To this thesis of the presence (παρουσία) of the universal in the particular the Neoplatonists also clung. Plotinus united in the νοῦς the separated ideas of Plato and constituted that νοητὸς νόητος, in which are gathered the "ideal reasons" of all things, arranged dialectically by genera, species and specific differences; but the soul of the world impresses these "ideal reasons" upon matter and makes them the very essence of things in the Aristotelian manner. In this way the universal is separated in the νοῦς, and is present and inherent in particular things, where, however, the Neoplatonists project the dialectical hierarchy of genera and species, of which they make as many different stratifications of physical reality, so that the same "animality" is in all animals, the same "horse-ness" in all horses, etc.
Porphyry, who in the Isagoge ad Categorias or De quinque vocibus had drawn the tree of these hierarchically ordered concepts, had also touched upon the problem whether genera and species are subsistent realities or concepts of our mind. Although he gives no solution to it, the very fact of having posed it spurred the search for one. The first to envisage one was Boethius. At the beginning of his commentary on the opuscule of Porphyry which he translated, he summarized the Aristotelian solution, namely that genera and species subsist only in individuals, but that nevertheless, thanks to the power of abstraction of the human mind, "intelliguntur praeter sensibilia". And again: "Sunt quidem in singularibus, cogitantur vero universalia; nihilque aliud species esse putanda est, nisi cogitatio collecta ex individuorum dissimilium numero substantiali similitudine". But in expounding this doctrine, he informs us that Plato "genera et species ceteraque non modo intelligi universalia, verum etiam esse atque praeter corpora subsistere putat".
The reading of Porphyry's little book and Boethius's commentary on the Categories provided the occasion for the disputes in the medieval schools of dialectic. But it must not be forgotten that the Platonic ideas, already united by Plotinus in the νοῦς, the first emanation of the One, had been transferred by St. Augustine into the divine mind, and constituted the "ideal" or "primordial reasons" of created beings. Neoplatonic thought, moreover, besides acting upon St. Augustine, had strongly influenced the writings of Pseudo-Dionysius the Areopagite. Of the Augustinian doctrine and that of Pseudo-Dionysius are certainly tributary Scotus Eriugena (v.), Remigius of Auxerre and Gerbert of Aurillac (Pope Sylvester II), who attribute to universals not only a real existence as ideas in the divine mind, but also as stratifications of reality upon which are projected all the degrees of logical abstraction. As for the reality of the ideas in the divine mind (ideas ante rem) all Christian thinkers were agreed. The point on which they disagreed concerned the existence of universals in re. Realism was the name given to that tendency which held genera and species to be so many stratifications of physical reality, so that one and the same identical nature, e.g., of animal, was differentiated in its species, and one identical specific nature, e.g., of horse, was differentiated in individual horses. And since it was the custom in the Middle Ages to transfer dialectic into theology, in whose service it was placed, Odo of Tournai thought that the individual is not a substance, but a "proprietas" of the substance "man", and held that only in this way could it be explained how Adam's sin, infecting human nature, numerically identical in all men, was transmitted to all descendants (Pl. 160, 1079 and 1090). But the greatest representative of Neoplatonizing realism was William of Champeaux (v.), at least until Abelard forced him to modify substantially his realistic doctrine. The Anselmian realism, on the other hand, is contained within the limits of Platonic-Augustinian realism, although Anselm, polemicizing against Roscelin, lets slip a phrase of rather realistic flavor (De fide trin., c. 2), which has made historians raise their eyebrows. Neoplatonic and Eriugenian realism, on the other hand, continues in the school of Chartres, with Bernard and Theodoric of Chartres and Clarembald of Arras (12th century); with Amalric of Bène and with David of Dinant it issues outright into pantheism.
A Neoplatonic realist current likewise exists among the Arabs, with the pseudo-Empedocles' book On the Five Substances, with the so-called Theologia Aristotelica, and with the Liber de causis; and among the Jews, with the Fons vitae of Avicebron or Ibn Gabirol (11th century).
Opposed to the realist current was the nominalism (v.) of Eric or Henry of Auxerre, of Raimbert of Lille and above all of Roscelin (v.), accused by St. Anselm of falling into tritheism. These "heretics of dialectic," Anselm said of the nominalists, "non nisi flatum vocis putant esse universales substantias"; so that, being unable to understand "quomodo plures homines in specie sint unus homo" (this is precisely the excessive phrase that the abbot of Bec let slip), he will not be able to understand either "quomodo plures personae, quarum singula quaeque est perfectus Deus, sint unus Deus."
But with the return of Aristotle, these extreme positions were bound to be abandoned. Among the Arabs, the renewer of the Aristotelian doctrine concerning universals is Averroes (12th century). For this celebrated commentator, "universalia... sunt collecta ex particularibus in intellectu, qui accipit inter ea similitudinem et facit unam intentionem" (Metaph., XII, comm. 4); so that "intellectus est, qui facit in rebus universalitatem" (De anima, I, comm. 8). In particular things there is really only the similitude; only through a process of abstraction is this fixed in a universal concept.
In the course of the 12th century Aristotle's Metaphysics and De anima began to spread in the Latin West as well, so that the theory set forth by Boethius concerning universals could be better understood. Abelard had already envisaged a solution to the problem different from that of Roscelin and William of Champeaux. In place of the voces of the nominalists he substitutes sermones, since the former are mere flatus, whereas the latter imply a logical function. And other intermediate solutions had been envisaged. But it was knowledge of the Metaphysics and the De anima, as well as of the Averroistic commentary, that restored the Aristotelian doctrine concerning universals to first place. St. Thomas, who in the 13th century was the most steadfast champion of this doctrine, is in agreement on this subject with Averroes.
The metaphysical presupposition of this doctrine, which is characterized as "mitigated realism," is this: the universal, known by an act of thought, has a foundation in physical reality, insofar as the form constitutes the ὅσια κατὰ τὸν λόγον of things (Aristotle, De anima, II, c. 1, 412ᵃ, 5 ff., 412ᵇ 10 ff.) and is, in itself, universal like the Platonic idea.
This Aristotelian-Averroistic-Thomistic theory is the one that prevailed in Scholasticism from the 13th century onward.
Nevertheless it is not difficult to find traces of Neoplatonism, for example, in the Summa philosophiae, attributed to Robert Grosseteste, published by L. Baur in Beitr. Gesch. Philos. Mitt., IX, Münster in W. 1912, where it is maintained (pp. 351-52) that genera and species "veras aliquas naturae dicunt et non solus intentiones logicalis." Connected with this theory is that of the plurality of forms in natural beings, which maintains that the generic form is really distinct from the specific form and this from the "most specific species" (John of Jandun, De anima, I, qq. 8-9; Phys., VII, q. 8; Metaphys., II, q. 11); and from this thesis derive the famous "realitates" or "formalitates" of Duns Scotus (v.) and his school, which differ among themselves "a parte rei."
A pronounced realist tendency is also noticeable in John Buridan, followed by John Wyclif, and by Paul of Venice, who carried it from Oxford to Padua, where it was upheld by Nicoletto Vernia, on the question "utrum dentur universalia realia," and vigorously combated by Pietro Pomponazzi. Alessandro Achillini, author of a short treatise De universalibus (Bologna 1501), remained on the Aristotelian position av695.
The Aristotelian thesis, as has been seen, contains a twofold element: one subjective and epistemological, the universalizing activity of the intellect; the other objective and metaphysical, the form existing in things. In modern philosophy there is a tendency to develop the first element more and more and to eliminate the second. William of Ockham (v.) is the leader of the so-called nominales of the 14th century. Having affirmed the precedence and pre-eminence of intuitive over abstractive knowledge, the universal remains merely a function of the latter, which never reaches reality in its concreteness, but serves only to unify and order experience by means of termini, fictiones and intentiones in anima. Having driven from the world of nature the "substantial forms" and hidden "essences," Galilean and Cartesian physics reduces all phenomena to forms of mechanical motion: universal is only the law expressed in mathematical formulas. And it is precisely in mathematics that the universal seems bound to remain confined, while empiricism and sensualism proceed in the dissolution of the physical world, denying the reality of bodies, which Descartes had reduced to simple extended masses endowed with motion. Nevertheless Descartes recognized a universal and necessary value in innate ideas, which have their foundation in the ideas of the divine mind; an Augustinian thesis that, reworked by Malebranche, will be developed in ontologism. In the Spinozian system there is an "ordo et connexio idearum" that coincides with the "ordo et connexio rerum" (Eth., II, 19); a thesis substantially accepted also by Berkeley, for whom our perceptions ultimately originate from the ideas of the divine mind radiated upon created spirits, and are their symbol. A sharp denial of the universal and necessary value of ideas and of the principles of reason is found instead in Hume and then in positivism.
In the attempt to overcome the empiricist-rationalist antinomy, Kant made the universals the a priori forms of knowledge within which the subject orders experience: thus all our knowledge, as to content, derives from contingent and mutable experience; and all of it, as to the a priori and universal form that illumines and conditions experience itself, is logically prior to it. True knowledge is only the a priori synthesis. Having thus accentuated the universalizing function of the knowing subject, post-Kantian idealism transferred this function into the absolute I, which for Hegel is Idea, which, even in its becoming, preserves its transcendent absoluteness and resolves all reality into itself.
In the reaction against Hegelian idealism, positivism found itself greatly embarrassed in justifying the universal value of science. A. Comte held that mathematics, placed at the summit of knowledge, could suffice for the purpose. But empirio-criticism, contingentism, intuitionism and pragmatism have attacked the universal even in the stronghold that seemed impregnable, that of mathematics, stripping this science of all theoretical value and leaving it a purely utilitarian and economic abstractive function.
This thesis, for certain elements of truth that it contains, has been accepted also in the Crocean system of the philosophy of spirit, which relegates the sciences of nature and mathematics among pseudo-concepts, and reserves solely to the universal and concrete theoretical judgment the function of universalizing reality in the living unity of thought.