Theory and History of Ontology ( Raul Corazzon | e-mail:

Aristotle and the Science of Being qua Being. Ancient and Modern Interpretations

Contents of this Section

The Philosophy of Aristotle


Aristotle gives four definitions of what is now called metaphysics: wisdom, first philosophy, theology and science of being qua being.

The purpose of this page is to present some of the most important interpretations, ancient and contemporary, of the definition of a science of being qua being.

The main points that will be developed are the following:

A panorama of current interpretations;

A discussion of the authenticity of the Book K (XI) of Aristotle's Metaphysics;

Citations from the most important Greek and Latin Commentators about Aristotle's definition of a science of Being qua Being;

A brief presentation of the theory of reduplication (qua-theory):

An Annotated bibliography of contemporary research.

Why Aristotle does not simply say that ontology is the theory of being? Is there any difference between 'theory of being' and 'theory of being qua being'? In brief, the problem is deciding whether the two expressions 'the theory of being' and 'the theory of being qua being' are equivalent. If they are, the functor ' qua' does not seem to play any interesting role. On the contrary, if the two expressions are different -- that is to say, if there is a difference between the theory of being (simpliciter) and the theory of being qua being -- we should study the role played by the functor of reduplication ' qua'.

For an introduction to the problem of reduplication see Roberto Poli, "Qua-theories", in Liliana Albertazzi, (ed.), Shapes of Forms, Dordrecht: Kluwer 1998, pp. 245-256.

It should be noted that the functor of reduplication is massively used by Aristotle in his theory of mathematics (see in particular Met., books XIII and XIV). Reduplication is the tool Aristotle uses for avoiding the pitfalls of Platonism.

Aristotle's texts on being qua being

The sentence ὂν ἢ ὀν (Being qua Being) is used only in the books IV, VI and XI of the Metaphysics.

References are made to: Aristotle, Metaphysics. Text and Commentary, Edited and translated by William David Ross, Oxford: Oxford University Press 1924, corrected edition 1953.

Aristole's Metaphysics in a nutshell

"What were Aristotle's metaphysical contentions, and what is Aristotle's Metaphysics? The latter question is the easier. The work, as . we now have it, divides into fourteen books of unequal length and complexity. Book Alpha is introductory: it articulates the notion of a science of the first principles or causes of things, and it offers a partial history of the subject. The second book, known as "Little Alpha," is a second introduction, largely methodological in content. Book Beta is a long sequence of puzzles or aporiai: possible answers are lightly sketched, but the book is programmatic rather than definitive. Book Gamma appears to start on the subject itself: it characterizes something which it calls "the science of being qua being" -- and it then engages in a discussion of the principle of non-contradiction. Next, in book Delta, comes Aristotle's "philosophical lexicon": some forty philosophical terms are explained and their different senses shortly set out and illustrated. Book Epsilon is brief: it returns to the science of being qua being, and also passes some remarks on truth. Books Zeta, Eta and Theta hang together, and together they form the core of the Metaphysics. Their general topic is substance: its identification, its relation to matter and form, to actuality and to potentiality, to change and generation. The argument is tortuous in the extreme, and it is far from clear what Aristotle's final views on the subject are -- if indeed he had any final views. The following book, Iota, concerns itself with the notions of unity ('oneness') and identity. Book Kappa consists of a resumé of Gamma, Delta, and Epsilon and of parts of the Physics. In book Lambda, we return to the study of beings and of first principles: the book contains Aristotle's theology, his account of the 'unmoved movers', which are in some sense the supreme entities in his universe. Finally, Books XIII and XIV turn to the philosophy of mathematics, discussing in particular the ontological status of numbers." (pp. 66-67)

From: Jonathan Barnes (ed.), Cambridge Companion to Aristotle Cambridge: Cambridge University Press 1995. Chapter 3: Metaphysics, by Jonathan Barnes.

"Aristotle can fairly be said to be the founder of metaphysics as a separate discipline, as well as one of the most influential theorists of metaphysics. (...) Aristotle was not the first philosopher to concern himself with metaphysical issues, but he was the first to study metaphysics systematically and to lay out a rigorous account of ontology. (...) In the Metaphysics Aristotle subjects to scrutiny his own metaphysical principles. Our word 'metaphysics' itself derives form the expedient of early editors of Aristotle who, not knowing what to call his books on first principles, called them META TA PHYSIKA, the material after the physical enquiries. Whether the fourteenth books of the Metaphysics are a unity or a collection of disparate treatises is a matter of serious debate. Aristotle clearly recognizes a special study corresponding to metaphysics which he calls variously wisdom, first philosophy, and theology.

But the books of the Metaphysics seem to present different conception of what metaphysics is. In Book I Aristotle identifies wisdom with knowledge of the ultimate causes and principles, which he identifies as the four causes. Book IV makes metaphysics an enquiry into the causes of being qua being, an enquiry made possible by the fact that all senses of being are related to a single central notion, the notion of substance. Book VI argues that the highest science must study the highest genus of substance, which is the divine, and hence this science must be theology. Of course, it is not surprising that metaphysics should take in studies of causation, of ontology (the study of the basic entities in the world), and what was later called special metaphysics (the study of special kinds of beings, e.g. God and the soul); but precisely how these enquiries were related in Aristotle's mind remain obscure." (vol. I, pp. 50-52)

From: Hans Burkhardt & Barry Smith (eds.), Handbook of Metaphysics and Ontology, München: Philosophia Verlag 1991, entry Aristotle, by Daniel W. Graham.

An hypothesis about the title of the Metaphysics

In an essay published in 1954 (1), Hans Reiner proposed a new interpretation of the origins of the title of Aristotle's book.

His hypothesis is summarized by Takatura Ando in: Metaphysics. A Critical Survey of Its Meaning, The Hague: Martinus Nijhoff 1963, pp. 4-5.

"According to Reiner, it would have been a quite arbitrary procedure to christen the science, which Aristotle himself called the first philosophy, and Theophrastus the first theology, with a name derived by chance from the mere editorial sequence of the work. The interpretations of this book by Alexander of Aphrodisias and by Asclepius, on which modern scholars like Brandis, Zeller, and Bonitz base the above mentioned hypothesis [that the title is due to Andronicus of Rhodes], tell us in reality that the book was called ta meta ta fisika, because it came after the physical sciences. Rather then mentioning anything about its origin from Andronicus' arbitrary arrangement, Alexander and Asclepius said that the order was taxix proz hmaz. Anyone who has learned a little about Aristotle's philosophy must know that prox emax usteron is the contradictory opposite of prox emax proteron, which on its side, is the contrary of fusei proteron. Metaphysics is posterior to physical sciences in the order in which we learn things, and this is consistent with calling metaphysics prote filosofia, first philosophy, i.e. prior in the order of being. (...) The name metaphysica, Rainer proceeds, cannot be found even in Diogenes Laertius, the oldest catalogue of Aristotle's works. The first person to use this title if Nicolaus of Damascus, who lived in the latter half of the first century B.C. In a commentary on Theophrastus metaphysics -- this book had also originally another name -- we find that Nicolaus of Damascus wrote a book on Aristotle's meta ta fusica. (...) Though as we have already said we cannot find it [metaphysics] in the list of Diogenes Laertius, it seems very probable that it was included in an earlier list -- that of Hermippus (ca. 200 B.C.) -- and was by some chance dropped from the list of Diogenes. According to Howald, Ariston of Ceus who was master of the Peripatetic school fro 228-5 B.C. made a list of philosophical works before Hermippus and Diogenes presumably used this when he made his list. The origin of the name metaphysics, thus traced back to one century after Aristotle's death, might be safely conjectured to reflect the sequence which Aristotle himself followed. (...) Eudemus, Aristotle's immediate disciple, the author of the History of Theology, and the first editor of his teacher's works, is supposed by Reiner to have invented the name ta meta ta fusica."

N.B. The Bibliographical references of the works cited can be found in the Selected Bibliography


Reiner, Hans. 1954. "Die Entstehung Und Usprüngliche Bedeutung Des Names Metaphysik." Zeitschrift für philosophische Forschung no. 8: 210-237.

Reprinted in: Fritz-Peter Hager (ed.), Metaphysik und Theologie des Aristoteles, Darmstadt: Wissenschaftliche Buchgesellschaft 1969 pp. 139-174; translated as: "The Emergence and Original Meaning of the Name "Metaphysics"," in: Graduate Faculty Philosophy Journal, 13, 2, 1990 pp. 23-53.

The debate about the evolution of Aristotle's thought

"For most of this century, Aristotelian scholarship was dominated by a single question: how might Aristotle's intellectual development be used to shed light on his philosophical doctrines? Opinions differed widely as to how this growth might be charted; eventually, a reaction to the whole enterprise set in. The past thirty years have seen the question lose its prominence as scholars returned to studying the corpus without Aristotle's development as a primary concern.

Recently, the question of the Aristotle's philosophical development has been reopened. Two books in particular, Daniel Graham's Aristotle's Two Systems (Oxford, 1987) and John Rist's The Mind of Aristotle: A Study in Philosophic Growth (Toronto, 1989), have advanced comprehensive developmental accounts of the whole of Aristotle's thought. Together they may signal a renewed interest in developmentalism, and offer philosophers an opportunity to assess the problems and prospects facing any such revival. (...) For fifty years after it was first raised, to little notice by Oxford professor Thomas Case (Case 1910), then resoundingly by Werner Jaeger in a groundbreaking study two years later (Jaeger 1912), scholars devoted themselves to the question of Aristotle's growth as a thinker. Jaeger's 1912 study concentrated on the development of Aristotle's Metaphysics; in 1923, he furnished a comprehensive account of the whole of Aristotle's growth, which revolutionized the study of the philosopher (Jaeger 1923; all references are to the 1948 second English edition except as noted). The main points of his thesis are familiar (though perhaps no longer familiar enough: see Code 1996). Aristotle began his philosophical career as a follower of Plato and only later, after a long transitional period, emerged into philosophical maturity as the opponent of Platonic forms and the investigator of empirical nature and living things. Much of Jaeger's evidence for the early Aristotle came from fragments of the literary remains, many of which had been regarded as spurious before his work. He then turned to works often regarded as assemblages of independent lectures or smaller pieces (the Metaphysics and Politics in particular) and to the three ethical treatises that have come down to us under Aristotle's name. Using these works he constructed a picture of Aristotle's development in which Aristotle moved toward an increasing independence from Plato. He then sought parallels with doctrines in other works not held to be internally inconsistent. So, for instance, his contention that Aristotle's empiricism came late in his career led to his assigning the biological works to the Lyceum period.

Almost immediately, the genetic question came to dominate Aristotelian scholarship (see Chroust 1963, also A. Mansion 1927). (...) Cherniss (1944) argued forcefully that, given Aristotle's constant revision of his lectures until the end of his life and the clear programmatic connections between many of them, interpreters are compelled to take his doctrines as a unified whole. Others sought to dismiss Jaeger's approach as being simply the product of positivist or historicist dogmas popular in Germany at the turn of the century.

Gradually, Jaeger found himself with fewer and fewer supporters for his version of the developmental thesis. Probably the decisive challenges came in the work of Düring and Owen. During (1956, 1966a, 1966b) argued that Aristotle was from the beginning opposed to Plato and his transcendental view of reality. His growing interest in natural science developed, in turn, under the influence of Aristotle's own gifted pupil and eventual successor, Theophrastus. Owen's analysis (1960, 1965) was yet more influential. Owen argued that early in his career Aristotle issued an uncompromising rejection of Platonic metaphysics and the corresponding master science of dialectic. Later, a pivotal insight into how we refer to one thing by means of another -- the now famous doctrine of 'pros hen equivocity" of 'focal meaning' -- prompted him to make room for a universal science of Being after all. In effect 'the Platonism of Aristotle' was more complex that Jaeger had pictured it (and perhaps more so than Owen thought -- see Code 1996)." (Introduction by William Wians, pp. IX-XI.)

From: William Wians (ed.), Aristotle's Philosophical Development: Problems and Prospects, Lanham: Rowman Littelfield Publishers 1996.

"Turning to Aristotle's own works, we immediately light upon a surprise: Aristotle began his extant scientific works during Plato's lifetime. By a curious coincidence, in two different works he mentions two different events as contemporary with the time of writing, one in 357 and the other in 356. In the Politics (V 10, 1312b10), he mentions as now (nun) Dion's expedition to Sicily, which occurred in 357. In the Meteorologica (III 1, 371a30), he mentions as now (nun) the burning of the temple at Ephesus, which occurred in 356. To save his hypothesis of late composition, Zeller resorts to the vagueness of the word "now" (nun). But Aristotle is graphically describing isolated events and could hardly speak of events of 357 and 356 as happening "now" in or near 335. Moreover, these two works contain further proofs that they were both begun earlier than this date. The Politics (II 20) mentions as having happened lately (neosti) the expedition of Phalaecus to Crete, which occurred towards the end of the Sacred War in 346. The Meteorologica (III 7) mentions the comet of 341. It is true that the Politics also mentions much later events, e.g., the assassination of Philip, which took place in 336 (V 10, 1311b1-3). Indeed, the whole truth about this great work is that it remained unfinished at Aristotle's death. But what of that? The logical conclusion is that Aristotle began writing it as early as 357, and continued writing it in 346, in 336, and so on till he died. Similarly, he began the Meteorologica as early as 356 and was still writing it in 341. Both books were commenced some years before Plato's death; both were works of many years; both were destined to form parts of the Aristotelian system of philosophy. It follows that Aristotle, from early manhood, not only wrote dialogues and didactic works, surviving only in fragments, but also began some of the philosophical works that are still parts of his extant writings. He continued these and no doubt began others during the prime of his life. Having thus slowly matured his separate writings, he was the better able to combine them more and more into a system, in his last years. No doubt, however, he went on writing and rewriting well into the last period of his life; for example, the recently discovered Athenaion Politeia mentions on the one hand (c. 54) the archonship of Cephisophon (329-328), on the other hand (c. 46) triremes and quadriremes but without quinqueremes, which first appeared at Athens in 325-324; and as it mentions nothing later it probably received its final touches between 329 and 324. But it may have been begun long before and received additions and changes. However early Aristotle began a book, so long as he kept the manuscript, he could always change it. Finally, he died without completing some of his works, such as the Politics, and notably that work of his whole philosophic career and foundation of his whole philosophy -- the Metaphysics -- which, projected in his early criticism of Plato's philosophy of universal forms, gradually developed into his positive philosophy of individual substances, but remained unfinished after all.

On the whole, then, Aristotle was writing his extant works very gradually for some thirty-five years (357-322), like Herodotus (IV 30) contemplated additions, continued writing them more or less together, not so much successively as simultaneously, and had not finished writing at his death.

There is a curious characteristic connected with this gradual composition. An Aristotelian treatise frequently has the appearance of being a collection of smaller discourses (logoi), as, for example, K. L. Michelet has remarked.

This is obvious enough in the Metaphysics: it has two openings (Books Α and α); then comes a nearly consecutive theory of being (Β, Γ, Ε, Ζ, Η, Θ), but interrupted by a philosophical lexicon Δ; afterwards follows a theory of unity (Ι); then a summary of previous books and of doctrines from the Physics (Κ); next a new beginning about being and, what is wanted to complete the system, a theory of God in relation to the world (Λ); finally, a criticism of mathematical metaphysics (Μ, Ν), in which the argument against Plato (Α 9) is repeated almost word for word (Μ 4-5). The Metaphysics is clearly a compilation formed from Essays or discourses; and it illustrates another characteristic of Aristotle's gradual method of composition. It refers back to passages "in the first discourses" (en tois protois logois) -- an expression not uncommon in Aristotelian writings. Sometimes the reference is to the beginning of the whole treatise; e.g., Metaph. B 2, 997b3-5, referring back to Α 6 and 9 about Platonic forms. Sometimes, on the other hand, the reference only goes back to a previous part of a given topic, e.g., Metaph. Θ 1, 1045b27-32, referring back to Ζ 1, or at the earliest to Γ 2. On either alternative, however, 'the first discourses' mentioned may have originally been a separate discourse; for Book Γ begins quite fresh with the definition of the science of being, long afterwards called 'Metaphysics,' and Book Ζ begins Aristotle's fundamental doctrine of substance." (vol. 2 p. 506-507)

From: Thomas Case, Aristotle, Encyclopedia Britannica (1910). Reprinted In William Wians (ed.), Aristotle's Philosophical Development: Problems and Prospects, Lanham: Rowman & Littlefield, 1996, pp. 1-40.

"This book, being at once treatise and monograph, demands a brief word of explanation.

It does not seek to give a systematic account, but to analyse Aristotle's writings so as to discover in them the half obliterated traces of his mental progress. Its biographical framework is intended merely to make more palpable the fact that his previously undifferentiated mass of compositions falls into three distinct periods of evolution. Owing to the meagerness of the material the picture that we thus obtain is of course fragmentary; yet its outlines constitute a distinctly clearer view of Aristotle's intellectual nature and of the forces that inspired his thinking. Primarily, this is a gain to the history of philosophical problems and origins. The author's intention is, however, not to make a contribution to systematic philosophy, but to throw light on the portion of the history of the Greek mind that is designated by the name of Aristotle.

Since 1916 I have repeatedly given the results of these researches as lectures at the universities of Kiel and Berlin; even the literary form, with the exception of the conclusion, was established in essentials at that time. The literature that has since appeared is not very important for Aristotle himself anyhow, and I have noticed it only so far as I have learnt something from it or am obliged to contradict it. The reader will look in vain for the results even of earlier researches so far as they concern merely unimportant changes of opinion or of form; such matters have nothing to do with development. Still less has my purpose been to analyse all Aristotle's writings for their own sake and to complete a microscopic examination of all their stages. The aim was solely to elucidate in its concrete significance, by means of evident examples, the phenomenon of his intellectual development as such." (Preface to the German edition (1923)

From: Werner Jaeger, Aristotle. Fundamentals of the History of His Development, Oxford: Clarendon Press 1948.

"It can be shown, however, that even the earlier version of the introduction (Κ 1-8) is not the original form of the Metaphysics. We have seen that in Κ 1-8 metaphysics is described as the science of that which is unmoved and eternal and transcendent. We also find there, however, the definition of it as the science of being as such (ὂν ἢ ὀν), though not developed, as it is in the later version, into a science of the manifold meanings of being including the perceptible being of movable nature. This combination of the two definitions in K 1-8 is a serious difficulty, and becomes only too painfully obvious in the later version of E, which in its present revised form is meant to introduce the science of the manifold meanings of being. Since the earlier and the later versions do not differ in this respect, but only in the extension that they assign to the notion of being, we shall not fall into error if we use them both together in what follows.

In E 1 ( = K 7 ) Aristotle explains what he understands by a science of being as such. All sciences inquire into certain causes and principles of things. As examples he mentions medicine and gymnastics, and-to take one with a more developed method mathematics, i.e. the examples usual in Plato's theory of science and method. Each of these sciences marks off systematically a definite sphere of reality and a definite genus and studies the resulting limited complex of facts. None of them discusses the being of its object; they all either presuppose it on the ground of experience, as do natural science and medicine; or, like mathematics with its axioms, they start from particular definitions. Their demonstrations, which differ from each other only in degree of accuracy, deal solely with the properties and functions following from these definitions or from facts evident to sense. The metaphysician, on the other hand, inquires about being precisely as being. He examines the presuppositions of these sciences, of which they themselves are neither willing nor able to give an account.

Aristotle supplements this explanation at the beginning of Book E 1 ( = K 3), where he brings out even more fully and clearly the distinction between first philosophy as universal science and the special sciences, between being as such and its particular realms. Here he treats being not as a sort of object separate and distinct from others, but as the common point of reference for all states, properties, and relations, that are connected with the problem of reality. As the mathematician, according to him, looks at all things solely from the point of view of quantity, so the philosopher studies everything that belongs to being as such, whereas the physicist, for example, considers it only as in motion. Many things 'are' only because they are the affection or the state or the motion or the relation of some one being they derive from something that ' is' simply. (...) To Plato dialectic was as such ontology. To Aristotle it was rather a practical and historical question whether this whole logic of being was under all circumstances to be included in first philosophy. His original metaphysics was theology, the doctrine of the most perfect being; it was hard to combine abstract dialectic with this once the Ideas were gone. But he tried to link them up by means of their common relation to being as such." (pp. 214-216)

From: Werner Jaeger, Aristotle. Fundamentals of the History of His Development, Oxford: Clarendon Press 1948.

"According to Werner Jaeger, the ὂν ἢ ὀν has two different meanings, depending on whether it is considered as found in the more ancient books or in parts which would have been added to the collection of the Stagirite's Metaphysics in the last-period.

In 'the last' stage the theory of the ὂν ἢ ὀν, according to Jaeger, would signify a sort of 'ontological phenomenology,' that is, 'an enumeration and description of the various meanings of being' in which a place would be found for all the forms of being, while transcendent being will not hence forward be the center of interest itself. Thus understood, the ὂν ἢ ὀν permits Aristotle to unify the two preceding conceptions of Book Κ Λ Ε 1; one in which the predominant interest concerns the supersensible and transcendent substance, the other, Books Ζ Θ, in which the interest in sensible substance and immanent entelechy or immanent form predominates. In fact the ὂν ἢ ὀν comprehends both the pure energeia of divine thought and the αἰσθητη ουσια of the physical world which is subject to generation and corruption insofar as both are 'being.'.

This conception of the ὂν ἢ ὀν, as we said, would be contained only in the last additions, insertions, and articulations, chiefly in the second, the third, and the fourth chapters of Book Ε. In Book Κ, where according to Jaeger the object of first philosophy is indicated in 'a clear way and without exception' as being the immobile and eternal realities, the ὂν ἢ ὀν also appears close to this perspective, but here the ὂν ἢ ὀν is not developed yet, as it is in the later version, into a science of the manifold meanings of being, including the perceptible being of movable nature. The same ought to be said of the meaning of ὂν ἢ ὀν in Books Γ and Ε 1, which, on this account, are not even distinguished from Book Κ by means of 'the different scope with which it treats the concept of being. 'By excluding the doctrine of ὂν ἢ ὀν from Κ, Γ, and Ε 1 as having the meaning of an ontological phenomenology, as it will, on the contrary, be present in Ε 2-4, Jaeger only explains rather vaguely what it does signify in that first group of writings. With respect to Book Γ he writes: 'Here he treats being not as a sort of object separate and distinct from others, but as the common point of reference for all states, properties, and relations that are connected with the problem of reality. It would seem, therefore, that Jaeger considers it as a kind of general ontology, in the sense of a universal theory of being.' (Jaeger, - Aristoteles - p. 289, Robinson trans. p. 215)". (pp. 138-139 notes omitted)

From: Giovanni Reale, The Concept of First Philosophy and the Unity of the Metaphysics of Aristotle, Albany: State University of New York Press 1980.

Contempora interpretions: metaphysica as general ontology

The general science of causes is general ontology.

Gamma 1 begins with the assertion that there is a science that studies 'that which is' qua 'thing which is' and what belongs to 'that which is' intrinsically, or per se. (1) By virtue of its generality this science is contrasted with the departmental sciences that cut off merely some part of 'that which is' and study the properties that are unique to that part. To study 'that which is' qua 'thing that is' is not to study some special object called 'that which is qua thing that is'. The 'qua' locution is here used to indicate the respect in which this science studies its subject matter, and indicates that it deals with those ubiquitous truths that apply to each 'thing that is'. The metaphysician must both state the general (propositional) principles that apply to 'that which is' as such and treat of their properties or features. An example of a metaphysical principle that belongs to beings as such is the principle of non-contradiction (PNC). To study what belongs to 'that which is' per se also involves a study of the terms that apply to 'things that are' as such (for instance, 'same' and 'one'), and to investigate truths about them.

This concept of general ontology is further clarified by the way in which Aristotle proceeds to deal with issues raised by four puzzles stated in B 1 about the nature of the metaphysical enterprise itself. These are four of the first five items on the list, and they concern the characterization of the universal science that deals in the most general way possible with the causes and starting points of all things. The second puzzle (995b6-10), for instance, assumes that this science will at the very least deal with the principles of substance, and inquires whether it will also deal with the common axioms those principles 'from which everybody makes proofs'. Does it, for instance, study the PNC? I 3 solves this puzzle by showing that the science of substance is the science that studies the common axioms. Gamma also provides answers to at least portions of the other puzzles, though without explicitly referring back to them. For instance, after Book B has queried whether the science of substance also studies the per se accidents of substances, it goes on to ask whether it will study in addition to these accidents such terms as 'same', 'other', 'similar', 'dissimilar', 'contrariety', 'prior' and 'posterior', and then concludes by asking whether it will also study even the per se accidents of these last mentioned items. This is to ask whether in addition to investigating the definitions of the per se accidents of substance, it will also study such issues as whether each contrary has a single contrary. Gamma 2 is in part devoted to answering these last two questions in the affirmative." (pp. 57-58).


(1) 'That which is qua thing that is' translates 'to on hêi on', an expression often rendered as 'being qua being'.

From: Alan Code, "Aristotle's Logic and Metaphysics", in: C. C. W. Taylor (ed.), Routledge History of Philosophy. From the beginning to Plato, Vol. I, London/New York: Routledge, 1997.

"One of the most difficult problems of interpretation set by the Metaphysics lies in the fact that in book IV the 'sought-for science' is characterized very precisely as the science of 'being qua being' ( ὂν ἢ ὀν).(1) Unlike the particular sciences, it does not deal with a particular area of being, but rather investigates everything that is, in its most general structural elements and principles. This description fulfils the expectations the reader has derived from books I and III, which repeatedly aim at insights of the highest generality. But, on the other hand, and startlingly, we also discover that in Metaphysics VI 1 - only a few pages further on, if we exclude book V as not part of the collection Aristotle seems first to accept this opinion and then, immediately afterwards, to embrace its exact opposite. For in VI 1 we again find an analysis of the sciences designed to establish the proper place of 'first philosophy'. Here, however, Aristotle does not, as he did in book IV, distinguish the 'sought-for science' from all other sciences by its greater generality. First he divides philosophy into three parts: theoretical, practical, and productive; and then he splits theoretical philosophy into three disciplines. To each of these disciplines he entrusts well-defined areas as objects of research. The 'sought-for science', referred to in IV as the 'science of being qua being', he now calls 'first philosophy', and defines it as the science of what is 'changeless and self-subsistent (akinêton kai chôriston)'. He explicitly gives it the title of 'theology'. Physics and mathematics stand beside it as the two neighboring disciplines in the field of theoretical philosophy.

Such an unexpected conclusion to so extended an introduction to 'first philosophy' must seem strange to the reader. It is understandable that an author should see the fundamental philosophical science as universal ontology. We can also accept that a philosopher should elevate theology above all other sciences because of the importance of its object. But that Aristotle should attempt to undertake both enterprises in a single work surely violates 'the greatest duty of a philosopher', which, according to Kant, consists in 'being consistent'.(2)That Aristotle here contradicts himself has been the dominant view in textbooks and commentaries since the middle of the last century. When faced by such difficulties of interpretation, it is customary to seek help from philology. It seemed necessary to saddle Aristotle with an internal inconsistency; and yet scholars were unwilling to credit him with one. Might not philology show that Aristotle's text did not, after all, contain such an inconsistency? In this way, the problem has submitted to what might be called therapeutic surgery at the hands first of Paul Natorp [1887] and then, more recently, of Werner Jaeger ([1948], pp. 214-21). Natorp resorted to the classical remedy of the nineteenth century, the obelus. Jaeger replaced this by its modern and more lenient counterpart, stratification. The two attempts are, curiously, almost mirror images of each other: Natorp saw the 'theologising tendency' of VI 1 as the result of interpolations by a later hand into Aristotle's text. By making excisions in the text and by giving a somewhat violent interpretation to what was left, he attempted to obliterate this tendency. Jaeger, on the other hand, regards the problematical line of thought which culminates in the description of 'first philosophy' as theology not as the amateurish addition of anonymous epigoni but as the remains of an earlier theologising stage in Aristotle's own development.

The following discussion attempts to prove three points:

I. Both Natorp's and Jaeger's solutions,(3) which may be seen as the two end points of a whole spectrum of related solutions,' are contradicted by the text of the Metaphysics itself.

II. As opposed to these radical solutions, we find that a conservative treatment, based on a detailed analysis of the text is possible.

III. This interpretation, which defuses the supposed contradiction, reveals a characteristically Aristotelian mode of thought and argument -- a mode which can be discovered in other parts of the corpus too, and which merits the attention of anyone concerned to give an accurate portrayal of Aristotle's intellectual 'development'."

(1) Met. IV 1, 1003a21; 24; 31.

(2) Critique of Practical Reason (1787), p. 44.

(3) Thus Reidemeister in his important article 'Das System des Aristotele's' (now in K. Reiderneister, Das exakte Denken der Griechen, 1949, pp. 67-87) speaks of a certain 'refractoriness' which 'appears in Aristotle's thought as a double inclination that he could not overcome but is explicitly aware of' (p. 70). Reidemeister rejects, on good grounds, both the separate ascription of these inclinations to Aristotle's youth and to his maturity, and the early dating of books I-VI. And he has informed me by word of mouth that he does not regard the 'refractoriness' as a contradiction.

From: Günther Patzig, "Theology and Ontology in Aristotle's Metaphysics", in: Jonathan Barnes, Malcolm Schofield. Richard Sorabji (eds.), Articles on Aristotle, Vol. 3: Metaphysics, London: Duckworth 1979 (Originally published in German in: Kant-Studien, 52, 1960/61 pp. 185-205. (Translated by Jennifer and Jonathan Barnes).

The numbering of the books of Aristotle's Metaphysics

The books of Aristotle's Metaphysics are standardly referred to by their Greek numbering, i.e. by the letters of the Greek alphabet, because of the anomaly that after book 'I' there comes a short book labeled, as it were, not 'II' but 'i'. Translators have often called this 'book II', so that the following book is then called 'book III' in English, though in the Greek it is unambiguously entitled 'B', which means 'II'. This creates confusion, which is avoided by using the Greek numbering throughout. For those unfamiliar with the Greek alphabet, here are the relevant letters, and the confusing 'translation' of them into Roman numerals, which is found in translations of the Metaphysics but nowhere else:

Α = I

α = II


Γ = IV

Δ = V

Ε = VI



Θ = IX

Ι = X

Κ = XI




This peculiar numbering reflects a more important fact about the books themselves, namely that they do not form a single and well organized whole, and one should not think of them as intended for publication as they stand. Aristotle clearly did mean there to be a connected series of books which we could call his 'Metaphysics' but the writings that have come down to us under that title contain much that would have been either abandoned or re-formed in a final version. For example, book a, which is an alternative introduction, would surely have found no place at all; book A would certainly have been pruned of the material in the first half of chapter 9 (which reappears almost unchanged in chapters 4-5 of book M), and probably of other material in consequence. There is no book of the existing Metaphysics of which one can confidently say that it would have figured in the final version just as it now is."

From: Aristotle Metaphysics. Books Z and H, Translated with a commentary by David Bostock, Oxford: Clarendon Press 1994 p. IX.