FORMS, UNICITY AND PLURALITY OF

A subject of controversy in the Middle Ages that can be understood only in terms of the Aristotelian doctrines it presupposes. This article therefore treats the presuppositions on which the controversy was based, its origins, its historical development, and a brief evaluation of its importance in the history of thought.

Presuppositions. The thesis of unicity or plurality of forms is philosophical in nature. It is an application to a concrete fact of the Aristotelian metaphysical doctrines of potency and act and of matter and form (see potency and act; matter and form). It applies to all substances composed of matter and form. It may be formulated thus: whether in one individual, remaining essentially one, there are many substantial forms or only one. The essence of a natural thing is constituted from two principles: one potential, undetermined in itself yet determinable, namely, matter; the other actual, the determining factor that makes the thing what it is, namely, form. Incomplete in themselves, they tend naturally to unite so as to constitute one individual substance, the hoc aliquid, or composite, which, although possessing several perfections and activities, is essentially one. Three factors are essential in becoming: the starting point of the change, privation; its end, form; and an underlying subject, or substratum, persisting through the process. The substratum, though numerically one before the change, plays a double part: one positive, persisting in every transmutation, matter; the other negative, the absence of the preceding form, privation. Privation, however important in becoming, does not survive as a constituent element (Phys. 190a 14–192a 33; Meta. 1032a 15–1033b 19, 1055b 11, 1069b 32–4). The crux of the problem consists in determining (1) whether primary matter is absolutely passive potency or contains some actuality of its own (potentia activa ); (2) whether privation is the disappearance of all previous forms or is an incomplete form (incohatio formae ); and (3) whether substantial form, including virtually all preceding forms, confers on primary matter its complete and specific determination, and alone actualizes all its perfections and activities, or imparts one perfection only. In the first alternative, one must posit oneness of form; in the latter, plurality of forms.

Origins of the controversy. In the height of the controversy, john peckham asserted that the unicity thesis originated from the Averroist leaders (Registrum epistolarum, ed. C. T. Martin, Rerum Britannicarum medii aevi scriptores, 224 v. [London 1858–96; repr. New York 1964—] 3:842). The theory is Aristotelian in origin, not Averroist; the question was debated years before the Averroist movement arose (see averroism, latin). It impinged on the schoolmen with Avicenna's De anima (Venice 1508, v. 7, fol. 26v–27v), and was formulated by dominic gundisalvi (gundissalinus) in his own De anima [ed. J. T. Muckle, Mediaeval Studies 2 (1940) 44–7]. The discussion turned on the oneness of soul, admittedly a different question; but by systematically presenting Avicenna's statement and introducing the catchword "substance," Gundissalinus supplied the main features of the problem and set the basis of the unity thesis: the vegetative, sensitive, and rational, though separately three distinct substances, united in man are one simple substance. Nevertheless, in his De processione mundi (ed. G. Bülow, Beiträge zur Geschichte der Philosophie und Theologie des Mittelalters 24.3:30) and De unitate (ed. P. Correns, ibid. 1.1:8) he popularized Avicebron's theories on matter and form, on the various degrees of forms, and other tenets, thus providing the pluralists with their fundamental principles.

Historical development. The full implications of the problem dawned on the masters slowly and gradually. In its first phase it was restricted to psychology; later, when its metaphysical issue was grasped, it was extended to all composites.

Prior to Aquinas. In its earliest stage the investigation, after the pattern of Avicenna and Gundissalinus, centered in the plurality or unity of the soul in man. john blund (before 1210) and roland of cremona (1229–30) first broached the subject. Both supported the unity theory. Roland's proofs foreshadowed St. Thomas Aquinas's: Since one thing has one being (unicum esse ), it can have but one first perfection. And if the first imparts complete perfection, the second or third serves no purpose. The pluralists argued from the embryo-genesis theory, which later, with the support of Aristotle's De generatione animalium (736a 35–736b 5), became their strongest evidence throughout the controversy. With philip the chancellor (d. 1236) the inquiry moved from the unity of soul to the unicity of substance: "whether the sensitive and rational are rooted in the same substance." Some held that man possesses one soul comprising three distinct incorporeal substances, each exercising a special vital function. Others maintained that they were not three substances, but powers, or faculties, rooted in one soul, one substance. Philip's presentation of the question set the standard for the first half of the thirteenth century.

St. albert the great, perceiving its general and wider principles, brought the inquiry one step further. He identified substance and form, distinguished by Philip and others. Albert's considered view appears in De unitate intellectus: "In my writings I repeatedly repudiated the pluralist theory as an absurdity. Its inventors were not Aristotelians, but some Latins who knew not the nature of the soul. It is a fatal error to assert that one subject possesses many [plures with the manuscripts, not possibiles, as in the printed text] substances, for substances cannot be but forms" (Omnia opera, ed. A. Borgnet, 9:455). See S. Vanni-Rovighi, "Alberto Magno e l'Unità della forma sostanziale nell'uomo," Studi in onore di Bruno Nardi (Firenze 1955) 2:753–778.

To sum up, Aristotle was claimed by all litigants, and the supporters of unicity appealed also to Augustine. adam of buckfield, roger bacon, and Geoffrey of Aspall (see A. B. Emden, A Biographical Register of the University of Oxford to a.d. 1500, 3 v. [Oxford 1957–59] 1:60–61) were all pluralists; and so were, according to their own principles, robert grosseteste, thomas of york, and St. bonaventure. richard fishacre and richard rufus of cornwall remained undecided. But Philip the Chancellor, hugh of saint-cher, john of la rochelle, the Summa Fratris Alexandri, william of auvergne, Pseudo-Grosseteste's De anima, and St. Albert all defended the unity of substance in man, however imperfectly they understood it. Yet by admitting a medium uniting soul and body, or by distinguishing between substance and form, they showed their incomplete grasp of its implications. Even Albert, not being aware of the full implications of potency and act, failed to tackle certain difficulties, such as the elementary forms in inorganic bodies (mixta ). By granting exceptions, they weakened its metaphysical and universal value [see D. A. Callus, "The Origins of the Problem of the Unity of Form," The Dignity of Science, ed. J. A. Weisheipl (Washington 1961) 121–149; O. Lottin, Psychologie et Morale aux XII ^e et XIII ^e siècles (2d ed. Gembloux 1957) 1:463–479].

Thomistic Teaching. St. thomas aquinas brought the unicity thesis to its full maturity. Recognizing the confusions on the fundamental issue, he restated the problem anew. His innovation consists in linking the traditional thesis with Aristotelian doctrine, regarding it not as psychological but as metaphysical, based on the principle of contradiction. An exact concept of esse and unity, of primary matter and substantial form, and of the distinction between substantial and accidental form enabled him to demonstrate the intrinsic incompatibility of plurality of forms, whether juxtaposed, or hierarchically coordinated, or however disposed. Nothing is absolutely one except by one form, by which a thing has being, for a thing has both being and unity from the same source. If, therefore, a human being were living by one form, animal by another, and man by a third, it would follow that he is not absolutely one. If the intellectual soul is the form of the body, it is impossible that there be another substantial form besides the intellectual soul, as it is impossible for any accidental disposition or other medium to come between the body and the soul or between any substantial form and its matter. Since the intellectual soul virtually comprises all inferior forms, it does by itself whatever the imperfect forms do in other things (Summa Theologiae, 1a, 76.1, 3–8; De anim. 6, 9–11; De spir. creat. 1–3).

Primarily a philosophical problem, it became theological by implication. But the question itself was not new, and it had been debated peacefully until theological inferences impinged on it. The crisis flared up during Thomas's second regency in Paris (1269–72). His dictum that "all previous forms disappear with the advent of the substantial form" (Quodl. 1.4.1, Easter 1269) aroused fierce opposition from some theologians. The crucial issue concerned Christ's identity living and dead. Was Christ, living and dead, the same man? Was His body numerically the same on the cross and in the grave? Does the soul perfect the body immediately or by means of corporeity? Thomas answered that, soul and body being hypostatically united with the Divine Person in life and death, Christ living and dead was identically, or simpliciter, the same man. But since the soul makes the body human, at their separation, the soul remaining the same, Christ's body was the same in a certain respect, or secundum quid (Quodl. 2.1, Christmas 1269; ibid. 3.2.2, Easter 1270; ibid. 4.5.1, Easter 1271; cf. Summa Theologiae 3a, 50.5, Naples 1273). The form of corporeity, not being distinct from the specific form but one and the same with it, does not remain (Quodl. 12.7.1, Christmas 1270).

The univocity thesis was impugned, but not condemned, in Paris. It was included in neither the 1270 nor the 1277 syllabus. There is no foundation for a story that it was proscribed and that Thomas was excommunicated. This arose from a misinterpretation of roger marston [Quaestiones disputatae (Quaracchi 1932) 116–117; see D. A. Callus, "The Problem of the Unity of Form and Richard Knapwell, OP," Mélanges offerts a Étienne Gilson (Toronto-Paris 1959) 151–156].

The Oxford Crisis. Spared in Paris, the thesis was attacked at Oxford. The Dominican archbishop of Canterbury, robert kilwardby, on March 18, 1277, forbade the teaching that "the vegetative, sensitive, intellective principles are one simple form [12]. The absolute potentiality of prime matter [3]; the absence of any incomplete form in privation [4]; the immediate union of substantial form with prime matter [7, 16]; and the equivocal predication of a living and dead body [13]" were also not to be taught (Chartularium universitatis Parisiensis, 4 v. [Paris 1889–97] 1:558–560). Peter of Conflans, archbishop of Corinth, however, remonstrated with Kilwardby for condemning irreproachable theses, especially that of the unity of form, upheld as true doctrine by many masters. Kilwardby riposted that it is unintelligible that the specific form of the composite performs the activities of all imperfect forms, and at its presence they all pass away. This theory, he said, is false and against sense experience, faith, and morals. The true unity of forms consists in the aggregate of all incomplete forms, essentially different but coordinated, each performing its proper action, and thus constituting with the complete form one composite.

Kilwardby's Apologia prompted two vigorous replies—one from giles of rome with the Contra gradus et pluralitates formarum (before April of 1278), the other from giles of lessines with his De unitate formae (July of 1278), which is a constructive, comprehensive, and dignified treatise, in which all Kilwardby's arguments are objectively confuted. The unity thesis was attacked by william de la mare in his Correctorium Fratris Thomae, but it was defended by thomas of sutton in the Contra pluralitates formarum and in De productione formae substantialis (see correctoria). henry of ghent discussed the question in Paris without taking sides (Quodl. 1.4, 1276). Later, mainly because of theological prejudices, he stated that there are two forms in man but one in other compounds (Quodl. 2.2, Christmas 1277; ibid. 3.6, Easter 1286; etc.). And so it continued to be freely ventilated in the schools.

The controversy reached its final climax with Kilwardby's successor, John Peckham, who on Oct. 29, 1284, ratified the prohibition, singling out the unity tenet as a source of many absurdities. A long and painful struggle ensued between him and the English Dominicans. The crux of the dispute converged on whether the unicity thesis was compatible with Catholic doctrine. Peckham claimed that it was impossible, without the plurality theory, to safeguard the teaching on the Incarnation, the Eucharist, the resurrection of the body, and other Catholic articles. The Dominicans argued that the problem was not theological, but primarily philosophical, and therefore either answer was consistent with the faith. Since all Catholic doctrines could be explained effectively by either view, it could be discussed freely as an opinion. Moreover, since, on Peckham's own confession, this question was reserved to the Holy See, it was outside the archbishop's competency.

william de hothum, Dominican provincial, pointed out to Peckham that the proper way of determining a philosophical issue, when either solution might be adopted without danger to faith, was not by condemnation but by a solemn disputation. richard knapwell undertook this task in his disputed question "Whether faith about the essence of human nature united to the Word requires us to posit many forms." His purpose was not to attack the pluralist view nor to defend his own, but to show that both opinions could equally safeguard Catholic faith. He expounded them objectively, replied to both objections, and concluded: "All this is said without dogmatizing, or injury to a better opinion." Peckham, however, on April 30, 1286, condemned the unity thesis in itself and in all its implications as heretical and fruitful of heresies, and excommunicated its defenders (Rerum Britannicarum medii aevi scriptores 3:921–923). Contrary to Peckham's expectation and pressure, Rome did not ratify his censure. The reaction to the condemnation was strongly felt, and it was criticized vigorously in Paris (cf. godfrey of fontaines, Quodl. 3.5.207–208, 211; Christmas 1286). Knapwell disappeared from Oxford, but robert of orford, Thomas of Sutton, william of macclesfeld, and others vindicated the Thomist thesis.

The condemnation did not stop the controversy. It continued in scholastic disputations, treatises, and commentaries on the Sentences and on Aristotle. The condemnation had no juridical effect outside Peckham's province; yet it painfully hampered the freedom of discussion, causing perplexities and anguish of minds (cf. Henry of Ghent, Godfrey of Fontaines, loc. cit. ). In Oxford the hindrance was more deeply felt. john baconthorp, as late as the first half of the fourteenth century, is a striking example. Comparing Oxford with Paris, he deplored that, whereas the Parisians were free to accept whatever opinion they preferred, the Oxford masters were compelled to discuss it in Peckham's terms [Quaest. in 3 sent. 19.1 (Cremona 1618) 119–124; see D. A. Callus, "The Problem … and Richard Knapwell," 123–160].

Evaluation. The controversy was not a conflict between Dominicans and Franciscans. They certainly had a prominent share in it; but other religious and secular masters in theology and arts joined issue. Nor was it a hair-splitting question. Indeed it was of the highest metaphysical importance. It is an explanation of the essential unity of man and of any composite. The answer betrays two concepts of unity: composite unity and simple unity. The pluralists, considering the components in the structure of the composite as substantial entities, posited unity of composition, although they varied considerably in their interpretations. Thomas Aquinas, establishing the transcendental relation of matter and form on potentiality and actuality and on the real composition of essence and the act of being, necessarily postulated one simple substance, or form, in all composites. He made it the cornerstone of his metaphysics and a fundamental tenet of his synthesis [cf. Acta Apostolicae Sedis 6 (1914) 385]. The conflict, therefore, was between two opposite tendencies; two different interpretations of potentiality and actuality, of matter and form; two different methods of approaching philosophical problems. For the metaphysicians, the controversy over unicity or plurality of forms is of universal significance and permanent value, and it is as relevant in the twenty-first century as it was in the thirteenth.

See Also: scholasticism; essence and existence.

Bibliography: É. h. gilson, History of Christian Philosophy in the Middle Ages (New York 1955) 416–420, 735–740, complete bibliog. d. a. callus, "The Problem of Plurality of Forms in the Thirteenth Century. The Thomist Innovation," L'Homme et son destin d'après les penseurs du moyen-âge (Louvain 1960); The Condemnation of St. Thomas at Oxford (Aquinas Papers 5; Oxford 1946); "Two Early Oxford Masters on the Problem of Plurality of Forms: Adam of Buckfield—Richard Rufus of Cornwall," Revue néo-scolastique de philosophie 42 (1939) 411–445. a. c. pegis, St. Thomas and the Problem of the Soul in the Thirteenth Century (Toronto 1934). t. crowley, Roger Bacon: The Problem of the Soul in His Philosophical Commentaries (Louvain 1950). r. zavalloni, Richard de Mediavilla et la controverse sur la pluralité des formes (Philosophes médiévaux 2; Louvain 1951). a. forest, La Structure metaphysique du concret selon S. Thomas d'Aquin (Paris 1956). m. de wulf, Le Traité "De unitate formae" de Gilles de Lessines (Les Philosophes belges 1; Louvain 1901).

[d. a. callus]