176. Gilbert's Philosophy. -- In addition to an exhaustive study of the logical writings and deductive method of Boëthius, and of the new logical works commentated by Theoderic of Chartres though unknown to Abelard, Gilbert also conceived the idea of completing Aristotle's study of the Categories. Aristotle had studied in detail only the first four categories, substance and the absolute accidents of substance, formae inhaerentes, as Gilbert called them. The remaining six, the accidents which characterize a substance only in relation to another substance, formae adjacentes, were analyzed by Gilbert in his Liber Sex Principiorum. The book obtained a rapid celebrity; it was universally adopted as a text-book in the schools, was annotated by Albert the Great, quoted by St. Thomas and retained its popularity in the schools down to the end of the Middle Ages.

The fundamental principle of anti-realism is defended by Gilbert: essences exist only in individuals and are really multiplied in Nature.^{1} Then immediately the question arises: what is the origin, and what the value, of universal concepts? Gilbert answers: the mind compares and gathers together (colligit) the essential determinations (diversae subsistentiae) realized in numerous individual beings, and effects a mental union of the similar realities of these beings; and it is this similar element we call the genus or species.^{2} These two fundamental theses suggest an evident kinship between the thought of Gilbert and that of Abelard. The genus and species are the sum-total of the beings in which those similar realities are found, belonging in proper to each of them.^{3} (Cf. the "Collection" theory, 171, d.) It is certain that Gilbert opposed the extreme realism of Chartres; and it is equally certain that he propounded neither nominalism nor conceptualism in the sense nowadays accorded to these terms. The thesis of the similarity of essences as the foundation of the real validity of universal concepts, is asserted more clearly by Gilbert than by Abelard. Still, there are weaknesses in the metaphysics of the Bishop of Poitiers which forbid us to regard his theory on the Universals as the first clear, definite and decisive formulation of moderate realism: weaknesses which account, in some respects, for the wide diversity we find in the views of historians about Gilbert's teaching.^{4}

In every actual being, he distinguishes between the essential realities possessed by that being, and to which there correspond similar realities in other beings (subsistentia, id quo est), and the individual determination which gives that being its real existence (substantia, id quod est)^{5} He is inclined to exaggerate the distinction we must make between the common essence and the individualized essence and seems to regard the latter as a part really distinct from the former. Yielding to the same unfortunate tendency, he regards as separate and proper subsistentiae in the individual, certain transcendental attributes, such as unity, which are not really distinct from the being itself.^{6} These certainly are errors in metaphysics; they have no direct bearing, however, on the Universals problem: whatever be the nature of the distinction established by Gilbert between the metaphysical elements of being, these elements he endows with an existence that is not universal, but proper to each individual.

The subsistentiae, or formae nativae, are carefully distinguished by Gilbert from the Divine ideas, of which they are copies.^{7} He makes the form, when contrasting it with the matter, a mere property of the being, thus perpetuating the false notion about matter and form, prevalent at that period. No wonder, then, that Gilbert admits plurality of forms. He condemns pantheism; but in another way his metaphysical errors cause him some trouble in theology (186).

Gilbert was not a thorough thinker -- with a full, all-round philosophical system -- any more than Abelard was. Alongside pure scholastic doctrines, we find in him illogical drawbacks and shortcomings. So that even the leading philosophers of the middle of the twelfth century bear witness to that want of systematization which is one of the most obvious characteristics of the scholasticism of the period.

{1} "Unus enim homo una singulari humanitate . . . ut pluribus humanitatibus plures homines et substantiae."

{2} "Universalia quae intellectus ex particularibus colligit," etc.

{3} "Genus vero nihil aliud putandum est, nisi subsistentiarum secundum totam earum proprietatem ex rebus secundum species suas differentibus similitudine comparata collectio," etc. (Comment. on the De Trinit. in the Boëthii Opera, ed. Basil, 1570, pp. 1238, 1135. Cf. PRANTL, Geschich. d. Logik, ii., p. 219 sqq.).

{4} PRANTL calls him an ontologistic (?) realist, op. cit., ii., p. 221; STÖCKL, a conceptualist, op. cit., i., p. 277; CLERVAL, an extreme realist, op. cit., p. 262. The laconic judgment of John of Salisbury is not easy to interpret: "Universalitatem formis nativis attribuit. . . . Est autem forma nativa, originalis exemplum, et quae non in mente Dei consistit, sed rebus creatis inhaeret. Haec graeco eloquio dicitur eidos, habens se ad ideam ut exemplum ad exemplar; sensibilis quidem in re sensibili, sed mente concipitur insensihilis, singularis quoque in singularibus, sed in omnibus universalis" (Metal., ii., 17). The in omnibus universalis must evidently he consistent with the singularis quo que in singularibus, which latter phrase can leave no doubt as to Gilbert's anti-realism.

{5} "Genera et species, i.e., generales et speciales subsistentiae subsistunt tantum non substant vere" (op. cit., p. 1239).

{6} Op. cit., p. 1148. "Quod est unum, res est unitati subjecta, cui scilicet vel ipsa unitas inest, ut albo, vel adest, ut albedini. . . . Ideoque non unitas ipsa sed quod ei subjectum est, unum est." Cf. PRANTL, p. 221.

{7} Op. cit., p. 1141.