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Latin Medieval Commentaries on Aristotle's Categories

Introduction: the place of logic in Late Antiquity

"The centuries between Aristotle and Porphyry bequeathed few logical works to the early Middle Ages. Cicero wrote a Topics, professedly based on Aristotle's work on the subject, but probably derived from a later source. The book was quite widely read in the Middle Ages, at the time when Aristotle's Topics was unknown. A work attributed to Apuleius, and bearing the same Greek title (transliterated) as the De InterpretationePeri hermeneias – enjoyed a certain vogue among the earliest medieval logicians. For modern scholars, it is a useful source of Stoic logical theories; but its philosophical content is slight.

By the time of Porphyry, however, a development had taken place in the status, rather than the doctrine, of Aristotelian logic, which would be of great importance for medieval philosophy. Aristotelian logic had been adopted by the Neoplatonists and given a definite place in their programme of teaching. Whereas their use of Aristotle's philosophical works was piecemeal and distorting, his logic was studied faithfully as a whole. Aristotle had rejected the notion of Platonic Ideas; and he had consequently treated genera and species in his logic purely as class-designations for individual things. The Neoplatonists assimilated this approach, which contradicted the very basis of their metaphysics, by limiting the application of Aristotelian logic to the world of concrete things. Stripped of its metaphysical relevance, the tendency was for logic to become more purely formal than it had been for Aristotle. However, the extra-logical aspects of the Categories and the De interpretatione were too intrinsic to these works to be ignored; and the result was the growth of a body of philosophical discussion and commentary within the Neoplatonic logical tradition, only vaguely related to Neoplatonic metaphysics, and sometimes seemingly antithetical to its principles.

Porphyry himself did more than anyone to establish Aristotelian logic within the Platonic schools. He commented the Categories and the De interpretatione and wrote a short Isagoge (Introduction') to logic, which quickly became established as a prologue to the Aristotelian corpus. The Isagoge is devoted to explaining five concepts which play an important part in the Categories: genus, species, difference, property and accident. It illustrates well Porphyry's formal approach to logic; and he avoids a philosophical discussion of the nature of genera and species, listing various opinions, but refusing to discuss them further in a work which is designed as an introduction.

The language of philosophy in the Roman Empire was Greek. The few philosophers who wrote in Latin were of vital importance in transmitting the logical tradition to the Middle Ages, even -perhaps especially - where their activity was limited to translation and paraphrasing. From the circle of Themistius (c. 317-88) derives a Latin epitome of the Categories, known as the Categoriae Decem, much read in the ninth and tenth centuries. This work adds some further remarks, on quantity, space and the relationship between ousia and the other categories, to a summary of Aristotle's text. The author begins by treating Aristotle's text as a discussion of speech (133:1-8) -- a term he believes should principally apply to nouns and verbs which, unlike other words, designate things (133:11-15). He searches for a word which will include (that is, presumably, designate) all things, and arrives (134:16-20) at the conclusion that this word is ousia 'one of the ten categories'. This seems a fair enough conclusion from Aristotle's theory, since every thing is an ousia and can therefore be signified by the word ousia. But, a little later (145:25-146:2), the author produces a similar definition, but one which this time applies not to the word 'ousia', but the concept designated by it: 'ousia has no genus because it sustains everything'. The suggestion here is that ousia refers, not to the individual thing as in the Categories (although this definition is also given by the paraphraser), but to that which every individual has in common by virtue of being something at all. The implication may well not have been intended by the epitomist who, in general, tries to give a faithful impression of Aristotle's text; oversight or not, it proved influential.

Marius Victorinus seems to have been a prolific translator of philosophical and logical works into Latin. Augustine used his versions of the Platonists' books' (probably parts of Plotinus and Porphyry); Boethius - whose opinion of him was low - used his adaptation of Porphyry's Isagoge in his first commentary on it (see below, pp. 30-1); and there is evidence that he wrote a commentary on Cicero's Topics. But the only part of his logical work which reached the Middle Ages intact was a brief treatise De diffinitione, an aid to studying the Topics.

In the Middle Ages, the Categoriae Decem was attributed, wrongly, to Augustine. But Augustine's authentic comments about the Categories, as well as the misattributed work, made him an authority for the earliest medieval logicians. In the Confessions (iv.xvi.28), Augustine describes his first contact with Aristotle's treatise, which he found himself capable of understanding without the aid of his teacher. When he came to write his De trinitate, he included a discussion (v. ii. 3) of a type frequent among the Neoplatonists, about the Categories and their inapplicability to God. But he stated that ousia could be applied to God: indeed, that it was God to whom it most properly applied. This idea, fully consistent with Augustine's ontology (see above, pp. 15-16), was to influence ninth-century interpretations of the Categories. A short treatise, De dialectica, was also attributed to Augustine in the Middle Ages; and most scholars now accept its authenticity. The work is remarkable for its linguistic approach to dialectic. Having separated words into single and combined (I) - as Aristotle distinguishes at the beginning of the Categories between things said with and without combination - Augustine devotes most of his energies to discussing single words, how they gain their meaning and how 26 The antique heritage ambiguity is possible. Dialectic includes, says Augustine (iv), the discussion of the truth or falsity of sentences and conjunctions of sentences; but the treatise does not go on to consider this topic." (pp. 23-26)

From: John Marenbon, Early Medieval Philosophy (480-1150). An Introduction, London: Routledge & Kegan Paul 1983.

Note about the history of the Commentary genre

"It is generally assumed that Homer was the first author to be subjected to commenting, and I see no reason to dispute this most reasonable assumption. It is scarcely imaginable that anything meriting the name of commentary was composed before 400 BC, but by 300 BC the literary commentary must have been around for some time, and the philosophical commentary appears. The first one evidenced was by Crantor and dealt with Plato's Timaeus (2).

We have to wait almost half a millennium to find a fully preserved philosophical commentary. Indeed, the second- to third-century Aristotelian commentaries of Aspasius and Alexander of Aphrodisias are among the oldest commentaries on any text that we have got and among all preserved commentaries from Antiquity those on Aristotle or Plato are massively represented -- the two philosophers are in the heavyweight league together with the Bible and Hippocrates. The bulk of the preserved commentaries are from the fifth or the sixth century, with a special concentration of Aristotle commentaries in the sixth century. Most of them are in Greek, the most notable exception being Boethius' works, which belong in the sixth-century group.

The sixth century, then, was to have a very strong influence on the medieval approach to philosophical texts, whether in the East, where people read Aristotle with Ammonius, Simplicius and Philoponus at their elbow; or in the West, where Boethius alone made an impact as strong as that made by his three Greek colleagues together in the East. In the formative period of Western scholasticism in the twelfth century, commentators imitated the format and the formulae of Boethius' Aristotle commentaries, and even commentaries on Plato's Timaeus use a Boethian format rather than that used by Calcidius in his exposition of Plato's work. (3)

Teachers, whether ancient or medieval, Greek or Latin, would give their pupils a few hints about the general contents of the relevant text in their introductory lectures, which appear as proems in the written versions of commentaries. But much more important than those lectures were the compendia, the sort of books that since Antiquity have often carried the title of Introduction to... whatever the subject (Eisagogé, Introductiones...). Most of the extant ancient specimens, insofar as they are philosophical, are about logic. In principle, and sometimes in practice, such works can be independent of any particular authoritative text. Thus there is no reason to see Galen's Introduction to Logic as a sort of summary of one or two of the classics of logic. On the other hand, Boethius' Introduction to Categorical Syllogisms4 makes no secret of the fact that it tries to summarize the syllogistics presented in Aristotle's Prior Analytics, and for good measure, it starts with a summary of the doctrine of terms and propositions from the Perihermeneias. Basically the same matter is covered in Apuleius' Perihermeneias.

Boethius used a work by Porphyry for his models. We cannot tell for certain how closely he followed his model, but at least the general structure is likely to have been the same in Porphyry. If so, Porphyry's Introduction to the Categories (the Isagoge) and his Introduction to categorical syllogisms together offered a compendium of a very large part of the Organon.

A brief compendium of logic may also be found in Martianus Capella and an ultra-brief one in Cassiodorus. Together with Boethius they gave inspiration to the revitalizing of the compendium genre in medieval Latin scholasticism, with Peter of Spain's Summulae as the most famous specimen. The genre also survived in Byzantium, but only barely so -- only three reasonably complete ones are extant, dating from 1007, ca. 1260, and ca. 1325, respectively ; there is convincing evidence that not a lot more ever existed'. The typical Latin compendium or summulae is characterized by combining sections that summarize certain parts of the Organon with sections that deal with more recent parts of logic. This is not the case with the Byzantine compendia.

Most often people would read a compendium before they read the original texts. In that way the compendia could be very influential by preconditioning students for a certain way of reading the authoritative texts." (pp. 1-3)


(2) Referred to by Plutarch in De animae procreatione in Timaeo, and by Proclus in his In Timaeum. The sources do not allow us to decide whether his work was some sort of essay on the Timaeus or more like a series of explanatory notes on the text.

(3) Thus in the anonymous scholia on Timaeus published as Bernhard of Chartres, Glosae super Platonem. Edited by P.E. Dutton, Studies and Texts 107, PIMS, 1991.

(4) I use this title for the work of which the first version appears as De syllogismo categorico in Migne's Patrologia Latina 64, whereas the incomplete revised version appears as Introductio ad syllogismos categoricos. Christina Thomsen Thornqvist of the university of Gothenburg will discuss the title question in her forthcoming critical edition of the first version. [Anicii Manlii Severini Boethii De syllogismo categorico. Gothenburg: University of Gothenburg 2008.]

(5) See Patrologia Latina 64 : 813C " ipse Porphyrius ", and cf. 814C " Hos ergo quatuor in prima figura modos in Analytics suis Aristoteles posuit. Caeteros vero quinque modos Theophrastus et Eudemus addiderunt, quibus Porphyrius, gravissimae vir auctoritatis, virus est consensisse ".

(6) See S. Ebbesen, “Western and Byzantine Approaches to Logic”, in Cahiers de l'Institut du Moyen Age Grec et Latin, 62 (1992), pp. 167-178, at p. 172.

(7) Already in ancient times hypothetical syllogisms had been added to the Organon material, but then hypothetical syllogisms had also found their way into the commentaries on Prior Analytics.

From: Sten Ebbesen, "Late-Ancient Ancestors of Medieval Philosophical Commentaries", in Il Commento filosofico nell'Occidente latino (secoli XIII/XV) / The Philosophical Commentary in the Latin West (13 - 15th Centuries). Edited by Fioravanti Gianfranco, Leonardi Claudio, and Perfetti Stefano. Turnhout: Brepols 2002, pp. 1-15. Reprinted as Chapter 7 in: S. Ebbesen, Greek-Latin Philosophical Interaction. Collected Essays of Sten Ebbesen. Volume 1, Aldershot: Ashgate 2008, pp. 97-106.

Problems in Aristotle' Categories

"Among the main problems of Aristotle's theory of the categories are the nature of their members, their number and how this number is arrived at. We find these problems discussed in modern research (1), but they are also dealt with in medieval philosophy.

To have a better understanding of the theories of the categories, we would like to point out that, in our view, ancient and medieval authors took for granted a parallelism between thought and reality. By 'parallelism' we mean that they accepted that there are things that exist in reality, and that there can be, and is knowledge of those things. These things as conceived by human understanding are designated by a term. So human understanding involves a subjective element when the thing is conceived or named, but thanks to the parallelism, the thing conceived by man is also the thing in nature. Now different authors put emphasis on different things, i.e. either on the things conceived (the objective (point of view) or on the conception of things (the subjective point of view). The question need not be asked whether a kind of gap had to be overcome: there is no gap. (2)

In a number of studies, L.M. de Rijk has made a fruitful distinction between a name in its descriptive function and in its deictic function. The use of e.g. the term 'man' implies a descriptive function, by which we can describe the class of men, and a deictic function, by which we can refer to the members of the class. Within the latter he distinguishes between 'actuality' and 'factuality'. A term in its deictic function refers to things, though they need not factually exist, i.e. they are contingent. Signification of factual existence is a complementary function of the name.(3)

In the categories of being items are collected and ordered by which man can name reality, or by means of which he can form complex wholes (for instance 'white man'), and even propositions (for instance 'men are white'), by which he can speak about reality and refer to it in the way he wants. So the theory of the categories is fundamental for philosophy. One could even say that the choice of a particular theory of categories depends on what kind of a philosopher one is.

What is the nature of the members of the categories? Are these members primarily terms which refer to something in reality? Or are they things so far as, and only so far as, these are captured in a linguistic expression or thought? When the nature of the members of the categories has been determined, the question arises for medieval philosophers how they are divided, i.e. how many categories there are, and which. Is their number ten, which is usually supposed to be held by Aristotle. Can this number be established by proof (or deduction)? Especially from John Duns Scotus onwards, not only positive terms, which are a privileged group, are studied, but also non-positive terms, such as 'blindness', fictional terms (for instance 'chimera'), terms of second intention, negative terms etc., which complicates the interpretation of the categories." (pp. 183-184)


(1) See for a general survey of the problems, H. Baumgartner, 'Kategorie, Kategorienlehre', in J. Ritter and K. Gründer (eds.), Historisches Wörterbuch der Philosophie IV, Darmstadt 1976, cols. 714-725.

(2) See esp. L.M. de Rijk, 'Categorization as a Key Notion in Ancient and Medieval Semantics', Vivarium XXVI, 1 (1988), 1-19.

(3) L. M. de Rijk, 'Ist Logos Satz?', in M.F. Fresco a.o., (eds.), Heideggers These vom Ende der Philosophie. Verhandlungen des Leidener Heidegger-Symposiums, April 1984, Bonn 1989, 21-32.

(4) E. Lask, Die Logik der Philosophie und die Kategorienlehre, 1923 (1911) (Gesammelte Schriften 2, 4): Was für eine Kategorienlehre man wählt, hangt davon ab, was für ein Philosoph man ist.

From: Egbert Peter Bos and A. C. van der Helm, "The Division of Being over the Categories According to Albert the Great, Thomas Aquinas and John Duns Scotus". In E. P. Bos (ed.), John Duns Scotus (1265/6-1308): Renewal of Philosophy, Amsterdam: Rodopi 1998, pp. 183-196.

The importance of the Commentaries on the Categories

"Aristotle's Categories is the subject of an extensive number of commentaries and of an unusual amount of debate, and for good reasons.(1) To begin with, in spite of its relatively short length, it can be a rather difficult text to understand, even for the trained philosopher, to say nothing of those who are just beginning their study of philosophy. Yet, because it laid the foundation for many subsequent philosophical discussions in general, and for logic in particular, it was, during much of the Middle Ages, often the very first philosophical text students encountered. Even contemporary philosophers who are steeped in philosophy and who have studied the Categories in depth often find it difficult, albeit for different reasons. One difficulty, as the ancient commentators on the Categories recognized, is that Aristotle himself is ambiguous about the subject of the work. What exactly is he categorizing? Is it 'things that are' or 'things that are said' or something in between, such as a concept? Furthermore, depending on how one understands its purpose, the Categories can be seen in harmony with, in contrast to, or even in contradiction to, Plato's own theory of the five highest genera. For all of these reasons the Categories has historically acted like a magnet, attracting commentaries from Aristotelians, Platonists, and Stoics alike. Quite naturally, some of these commentaries defend Aristotelianism, whereas others defend either Platonism or Stoicism by attacking Aristotle's Categories. Finally, still others, especially during the Late Middle Ages, use the Categories as a means to expound their own philosophical systems in the process of interpreting Aristotle.

Though many of the ancient and medieval commentators, such as Porphyry, Boethius and Albert the Great, did write original treatises on philosophical issues, their commentaries are in themselves valuable contributions to philosophy, particularly those from the later Middle Ages.(2) Consequently, studies of the various commentaries, and especially those dealing with the Categories, are valuable projects, as the following Essays amply demonstrate. As Robert Andrews points out, medieval "Categories commentaries are the repository of centuries of analyses of the basic concepts of Western thought, all carefully organized and awaiting modern rediscovery." (3) And while most of those commentaries are still awaiting rediscovery, the following Essays, I hope, will convince everyone that the effort is worthwhile." (pp. 1-2)


(1) According to my count of the texts listed by Charles Lohr, roughly two hundred extant Latin commentaries on the Categories were written during the Middle Ages. Of course, this number does not take into account the commentaries that are not extant, nor the ones written in Greek, Arabic, or Hebrew. Cf. the lists of extant commentaries cited by Charles Lohr in Traditio, vols. 23-29.

(2) Compare Fr. Wippel's description of St. Thomas' commentaries: of his theological commentaries, "two are commentaries in the strict sense, i.e., on the De Hebdomadibus of Boethius and on the De divinis nominibus; the other two offer brief expositions of the texts of Boethius and of Peter and use them as occasions for much fuller and highly personal disquisitions by Thomas himself." John E Wippel, The Metaphysical Thought of Thomas Aquinas: From Finite Being to Uncreated Being (Washington, D.C.: Catholic University Press, 2000), p. XVIII.

(3) Robert Andrews, "Question Commentaries on the Categories in the Thirteenth Century,"Medioevo 26 (2001), 265-326, p. 266.

From: Lloyd A. Newton, "The Importance of Medieval Commentaries on Aristotle's Categories", in: Lloyd A. Newton (ed.), Medieval Commentaries on Aristotle's Categories, Leiden: Brill, 2008, pp. 1-8.

"The interest of Categories commentaries for the contemporary philosopher is worth reviewing. Categorization of items constituting the world is today called ontology; the medievals attempted to classify the world according to the ten categories of Aristotle. The modern accusation, that medieval philosophers were actually dealing with linguistic classification, was in fact acknowledged by many medievals. While the medieval treatment of some categories (and here I am thinking especially of relation) was arcane, resulting from a particular interaction of theology and philosophy, other discussions, such as on the nature of number, involved speculative thought comparable to modern reflections on the subject. Medieval discussions have contributed directly to the development of contemporary philosophical concepts, such as intentionality, "haecceity", and the distinction de ditto / de re. Medieval Categories commentaries are the repository of centuries of analyses of the basic concepts of Western thought, all carefully organized and awaiting modern rediscovery.

The study of the Categories is uniquely able to take advantage of the continuity and traditionalism of the Middle Ages. Not only was the Categories the first Aristotelian work introduced to the Latin Middle Ages, but it was the only work of dialectic available for several centuries, in one form or another. During the beginnings of Latin scholasticism, when the study of philosophy faced a struggle for acceptance, Church Fathers such as Tertullian and Peter Damian denounced all pagan learning, including Aristotle. Against them it was argued that the study of dialectic (and grammar) is useful for the correct interpretation of Sacred Writings. The utilization of the Categories during the period of the seventh through tenth centuries escaped censure in special measure because it was available in two vehicles associated with St. Augustine. Augustine' s De trinitate systematically analyzes whether each category can be applied to God. Boethius' s De trinitate – a model and paradigm of the application of dialectic to theology – follows the relevant sections of Augustine. Furthermore, to Augustine was mistakenly attributed the Themistian paraphrase De decem praedicamentis, (2) placating those who feared the pagan Aristotle. This work was utilized by commentators during the time when no complete work of Aristotle was accessible, as informatively recounted by Marenbon in From the Circle of Alcuin to the School of Auxerre.(3)

When the logica vetus began circulating with the commentaries of Boethius in the 11th century, (4) the Categories was packaged with Porphyry's Isagoge, a work purporting to be an introduction to and an explication of key concepts in the Categories. When the logica nova was introduced, the Categories was recognized as first in a ranked order of logical works; its subject matter, individual words, is requisite for the understanding of sentences (in De interpretatione), syllogisms (Prior analytic) and science (Posterior analytic). This order was later overturned by the terminist logicians, who proposed an analysis of language which treated sentences, rather than words, as fundamental." (266-267)


(2) Pseudo-Augustini, Paraphrasis Themistiana, ed. L. Minio-Paluello, Brill, Leiden 1961 (A.L. 1, 5).

(3) Marenbon, From the Circle of Alcuin to the School of Auxerre: Logic, Theology and Philosophy in the Early Middle Ages, Cambridge University Press, Cambridge 1981.

(4) Marenbon, From The Circle of Alcuin, 16.

From: Robert Andrews, "Question Commentaries on the Categories in the Thirteenth Century", Medioevo. Rivista di Storia della filosofia Medievale 26, 2001, pp. 265-326.