353. Bibliography. -- Editions of the Opus Majus in 1733 and 1750. Recent edition by BRIDGES, 3 vols. (Oxford, 1897-1900): very defective. Vol. iii. is a re-edition of a portion of vol. i., according to a new MS. At the end of vol. ii., the De Multiplicatione Specierum. Under the title, An Unpublished Fragment of a Work by R. Bacon, Dom Gasquet has published in the English Historical Review (1897) a long letter of Bacon's to Clement IV., which he believes to be the introduction to Bacon's work. The letter does bear directly on the work. BREWER, Fr. R. Bacon Opera hactenus Inedita (in the Rerum Britannicarum Medii Aevi Scriptores), published in 1859. Contains the Opus Tertium and the Opus Minus, both complete, and the Compendium Philosophiae. DUHEM, Sur un fragment, inconnu jusqu'ici, de l'opus tertium de R. Bacon (Arch. Francis. Histor., 1908). ROBERT STEELE has begun to edit Bacon's metaphysics. The Communia Naturalia are still in MS. Their publication will be of great importance for the study of Bacon's metaphysics. PÈRE HADELIN, O.M.C., a former pupil of ours, is preparing an edition of them, and will also publish a study on Bacon's philosophy. Portions of this work have already appeared in the Revue Néo-scolastique, 1906-1909. Cf. La synthèse doctrinale de R. Bacon (Arch. f. Gesch. d. Philos., 1907) by the same.

The editions of BRIDGES and BREWER contain biographies of Bacon and studies on his works. CHARLES, R. Bacon, sa vie, ses ouvrages, ses doctrines (Paris, 1861). DELORME, Bacon (in the Dict. Théol. Cath., t. ii., 1903): good (see 352, n. 2). NARBEY, R. Bacon et le mouvement scientifique du xiii^e s. (Rev. Quest. Histor., Jan., 1894). FELDER, op. cit., 237; Das Schulprogramm, pp. 380 sqq. A. DÖRING, Die beiden Bacon (Arch. f. Gesch. d. Philos., 1904, xvii., 3): unimportant. FLÜGEL, Roger Bacon's Stellung in d. Gesch. d. Philologie (Wundt's Philosoph. Studien, xix., 1902, pp. 164 sqq.). PICAVET, Nos vieux maîtres, Pierre de Maricourt, le Picard, et son influence sur R. Bacon (Rev. Internat. Enseignem., 1907). A fuller bibliography will be found in Delorme's art, in the Dict. Théol. Cath., and, from the scientific point of view, in LALANDE'S art. (310). PIERRE DUHEM, Un fragment inédit de l'opns tertium de R. Bacon, Ad Claras Aquas, 1909. Texte et Étude.

§ 2. NEO-PLATONIC DIRECTION.

353(b). General Features. -- Through the influence of Arabian works, and, more directly, of the Liber de Causis and the Elementa Theologica of Proclus in the version of William of Moerbeke (226), numerous theories of Platonic origin found their way into the philosophy of the thirteenth century. Though appearing only intermittently in Albert the Great and St. Thomas, they occupy a sufficiently important place in the works of others to warrant us in recognizing a Neo-Platonic direction of a strictly philosophical character in the thought of the thirteenth century. Those who represent this current of ideas admit the doctrines of the earlier scholasticism into their conception of the world, just as they admit Thomistic and Aristotelian elements, but they mould all alike in a Neo-Platonic setting and harmonize all more or less successfully with Alexandrian theories.

Yet there is a profound difference, which cannot be too strongly emphasized, between the ancient Neo-Platonism and the medieval: the monism or pantheism, which is the very soul of the writings of Plotinus and Proclus, is not only absent from those of Witelo and Theoderic of Freiburg -- the two best known Neo-Platonists of the thirteenth century -- but is expressly refuted by both the latter. Otherwise we should be obliged to regard their philosophy, like that of Scotus Eriugena, as anti-scholastic. Then, too, this Neo-Platonic current is of little importance^{1} as compared with scholasticism, or even with Averroïsm. For those two reasons Plotinus was no more the master of the philosophy of the thirteenth century than of that of the preceding centuries.

It is interesting to note that the Neo-Platonists we are about to deal with, were all remarkable as men of science, well versed in physics and mathematics.

353(c). Witelo: Life and Works.^{2} -- Born about 1230 in Salesia, a region that was slow to awaken to intellectual life, WITELO was educated in philosophy and the sciences in the University of Padua. Later on, at Viterbo, he met William of Moerbeke, whose influence on him was considerable. It was at the instance of William that he wrote his Perspectiva (about 1270),^{3} dedicating it to the latter. In this treatise Witelo describes the laws of the propagation of light, according to Albacen; it contains many striking and original observations on the function of mental association in the sensation-process, especially in the visual perception of the third dimension of space.

Witelo is probably the author of another unfinished work, De Intelligentiis, which Dr. Baeumker attributes to him, and which he apparently interrupted in order to write the Perspectiva. It is more philosophical in its contents than the latter. Witelo's other works are lost. He seems to have had some connection at Viterbo with the Roman Curia. He died soon after the year 1270, probably at Vicoigne lez Valenciennes.

353(d). Philosophical Teaching. -- Witelo's doctrines in metaphysics and psychology deserve some notice: they are an alloy of Neo-Platonism, as dominant element, with certain data from Aristotelianism and the earlier scholasticism.

The De Intelligentiis -- which sets forth all its theses according to a rigorously deductive method -- studies, in two parts, God, the First Cause, His nature and His knowledge (P. i.); and the primary Intelligences, their powers of cognition and of motion (P. ii.). The starting-point of this metaphysical system is not being-in-general (Aristotle), but the infinite being, God. All other things are but participations, in a descending scale, of the Divine being (Neo-Platonism); as the manifold can issue only from the One, and the simple includes all the perfections of the composite. The identification of being with light is one of the peculiarities of the treatise (cf. Plotinus). God is light; He is also act and substance (Aristotle). All other beings are light participated (St. Augustine). Though this notion of the diffusion of light serves to illustrate the mutual relations of all beings,^{4} especially the relations between God and the world, there is nowhere any hint of emanation, and the idea of monism is entirely absent.

Witelo's psychology is Platonic and Neo-Platonic; but at the same time it incorporates Aristotelian theories on the formation of ideas. The soul is a simple, independent substance. The action of light explains not only the spatial arrangement of bodies, but the vital force of living organisms and even the process of conscious cognition itself. The sensation, like the concept, is an essentially active phenomenon of the soul (virtus activa, Plato), while it is at the same time representative of reality (virtus exemplaris). Such activity and such reproduction can belong only to a spiritual substance, and since it is light, the active, reproductive phenomenon of cognition is not the reception of any action from without, but an auto-diffusion of the ego (sui multiplicatio). The role of the active and passive intellects (Aristotle) is thus modified; the active intellect has now not only to produce a determination on the sense-images, but to know the reality of things.^{5}

353(e). Theoderic of Freiburg: Life and Works. -- The Dominican, THEODERIC OF FREIBURG (Theodericus Teutonicus de Vriberg, probably Freiburg in Saxony), appears at Paris, first as a student (prior to 1285) and then (towards 1297) as master in theology. He tells us that on the question of the eternity of the world he assisted at the disputes of a solemnis magister -- Henry of Ghent, no doubt -- whose opinions on that matter he afterwards criticized. He occupied important administrative positions in his order. The latest certain information we have about him dates from 1310. It would have been in the opening years of the fourteenth century that he wrote his principal works. These bear witness to an astonishing fecundity and to an extensive and varied store of learning. Of most importance are: De Luce et Ejus Origine; De Coloribus; De Iride et Radialibus Impressionibus; De Miscibilibus in Mixto; De Intelligentiis et Motoribus Coelorum; De Tribus Difficilibus Articulis; De Cognitione Entium Separatorum; De Habitibus; and especially the De Intellectu et Intelligibili, in which he sums up his very original systematic conceptions.

353(f). General Influence. -- From three points of view Theoderic of Freiburg has an interest for the historian of ideas in the thirteenth century. As a man of science, he formulated a striking and original theory on the rainbow, a theory taken up afterwards by Descartes. He informs us that when he expounded it to the provincial of his order, the latter recommended him to commit it to writing. As a mystic he had many ideas in common with Eckhart. As a philosopher, he was a bold and original thinker. He readily differed from the communiter loquentes and the doctors of his own order; and he boasts of it. But then, he was at the same time an energetic upholder of the doctrinal innovations of Thomism on the great fundamental and much debated questions of scholasticism: unity of substantial form; passivity of primal matter and its essential incapacity to exist without some form or other; denial of the intrinsic impossibility of creation ab aeterno. On the other hand, he perpetuated the teaching of the earlier scholasticism on many points, favouring theories of Augustinian origin. He subscribed to doctrines such as the distinction between the two intellects, the essential difference between sensation and thought, the composition of bodies from matter and form: all doctrines which attach him as a member to the family of the scholastics.

But all those Thomistic and Augustinian elements are incorporated in a system that is more Neo-Platonist than Witelo's. The Elementa Theologica are quoted repeatedly, and Proclus is put on a level with Aristotle and St. Augustine. To believe the Dominican philosopher, those three great thinkers are entirely at one upon the doctrines expounded in his treatises. Like Witelo, it is principally his metaphysics and psychology that have an interest for the historian.

353(g). Philosophical Teaching. -- At the foundation of his metaphysics is the theory of the production^{6} of beings by intermediaries, in a descending scale of causality, secundum modum emanationis. The emanation idea, absent from Witelo's system, is dominant here, bringing Theoderic another step nearer the Alexandrian conception of things. The production of beings is not the direct work of God (against the common opinion). By what he describes as an ebullitio, the Deity produces pure intelligences (not to be confounded with the angels); from these in turn proceed the spirits that animate the heavenly bodies; from these again the visible beings of our earth. To the primordial act, the Divine logos from which the pure intelligences receive their being, belongs exclusively, in Theoderic's theory, the title of creative act, in the scholastic sense of the word.^{7} Since every agent in the causal hierarchy has both its being and its causality ultimately from God, it follows that the production of the celestial intelligences and the visible universe is indirectly His work. Furthermore, since finite beings are not mere prolongations or forms of the Divine energy (Neo-Platonism, cf. 85), but substances distinct from God and from one another, Theoderic clearly repudiates all suspicion of pantheism and transposes the Neo-Platonic theme, so to speak, into a key that is frankly scholastic.

It would be unreasonable, he further teaches, to deny the possibility of an eternal world (against Henry of Ghent; cf. St. Thomas). Nay, even although the world had no beginning, it would not be coeternal with God. For, God is supereternal (superaeternitas); the pure intelligences, including the intellectus agens, are eternal; the heavenly bodies had a beginning, but will have no end; terrestrial substances alone exist in time.

Common principles regulate all processes of intellectual production: every intelligence that proceeds from an anterior one receives and conserves its being from the contemplative act by which the generating intelligence knows the generated. The latter in turn knows the principle from which it proceeds (Proclus). The very being of every pure intelligence is thought (against St. Thomas); it is intellectus in actu per essentiam.

Corporeal substances are composed of matter and form. Matter is indeterminate and, as such, incapable of receiving the existential act (St. Thomas; against Henry of Ghent); the form is unique, the sole determining principle of the individual (St. Thomas); spiritual substances are not composed of matter and form (St. Thomas).

The soul, which is the substantial form of the body (Aristotle), is identical with its faculties (St. Augustine). For, the mysterious principle of its being is intellectus agens (abditum mentis; principium causale essentiae animae); but the latter is a pure intelligence, born of the Divine logos; whence it follows that, in the soul, being and action are identical. The soul's activity is differentiated only by the directions in which it is employed conformably to its natural inclinations (habitus, respectus). In the soul, everything is activity. It acts, as the stone falls, when the conditions for action are present.

All cognition is an active phenomenon. Sensation takes place not through the causal influence of the external object, but on the occasion of its presence. The ideology of Theoderic assumes a peculiar complexion from the application of his principles regarding the intellectus agens to the origin and genesis of our ideas. Rejecting and refuting the monopsychism of Averroës, he attributes to each individual man an intellectus agens which knows God, its Producer, and sees in Him the exemplar-ideas of all things: so that we can thus be said to know all truth in the rationes aeternae. What a novel and curious paraphrase we have here of the Augustinian thesis of the illuminatio divina! The intellectus agens, thus enriched with species intelligibiles of all things, transmits them to, or produces them in, the intellectus possibilis on the occasion of sense-perceptions, determining thereby the actual cognition of the abstract essences of things. The passive understanding is, in every man (against Averroës), a product of the active intellect; and if the latter does not incessantly fructify its treasures of wisdom in us, it is because the body is an obstacle to the soul's clearer vision. Another corollary is this: the passive intellect knows not only species intelligibiles and, through these, external things, but it also knows the intellectus agens, which, by knowing the passive intellect, gives the latter its being.

The will is a natural inclination of the soul, consequent on the presentation of a particular good by the vis aestimativa. It is necessarily moved towards the object so presented; it is a princibium non effectivum, sed tantum inclinativum.^{8} The universal representation, which is the product of the understanding, has nothing to do with our moral life.

353(h). Bibliography. -- BAEUMKER, Witelo, ein Philosoph und Naturforscher des xiii. Jahrh. (Beitr. z. Gesch. d. Phil. d. Mittel., Münster, 1908). Publishes the De Intelligenesis for the first time. Very exhaustive study on Witelo's life and works. It includes many important monographs on the medieval history of the proofs of the existence of God, on the philosophy of light, on the medieval Platonic ideology and on the theory of Intelligences. ENGELBERT KREBS, Meister Dietrich (Theodericus Teutonicus de Vriberg), sein Leben, seine Werke, seine Wissenschaft (Beitr. z. Gesch. d. Philos. d. Mittel., Münster, 1906): an excellent study. Krebs publishes in extenso the De Intellectu and the De Habitibus.

{1} "Unsere Schrift (De Intelligentiis) zeigt wie such die neuplatoniscbe Strömung einen wenn anch kleinen Kreis ergriffen hat." BAEUMKER, Witelo, em Philosoph und Naturforscher des xiii. Jabrhunderts (Beiträge z. Gesch. d. Philos. d. Mittel., Münster, 1908, p. 188. Cf. p. 604).

{2} Our materials here are taken from BAEUMKER's recent work on Witelo.

{3} About the same time Bacon and Peckham also wrote treatises on Perspective.

{4} It is interesting to note that St. Thomas combats the Neo-Platonic notion that "omne quod influit in alia est lux vel naturam lucis habens," with express references to texts of the De Intelligentiis, the author of which he does not mention by name: "Contrarium concedimus, quamvis liber De Intelligentiis non sit auctoritatis alicujus, nec etiam verum sit quod omnis influxus sit ratione lucis" (Quodl., vi., q. ii, art. 19. BAEUMKER, op. cit., pp. 420 sqq.).

{5} In the Perspectiva, Witelo solves the Universals problem after the manner of Bacon. There are in all things individual marks (in tentio es individuales) and specific features (intentiones speciales), to which correspond sense knowledge on the one hand and general knowledge on the other (ibid., p. 626). {6} This production he calls interior transfusio, qua aliquid fluit in aliud (p. 129); ebullitio; ordo emanationis ut scilicet unus ab alio et ab isto alms et sic deinceps fluat in esse (p. 133).

{7} ". . . hoc tamen in omnibus salvo quod solus Deus creat. . . quia quicquid agit causa secunda in essentialiter ordinatis agitur a causa superiori" (p. 132).

{8} De Cognitione Entium Separatorum. KREBS, p. 96.