Anna ZhyrkovaCorresponding authorORCID id

Leontius of Byzantium and the Concept of Enhypostaton
A Critical Re-evaluation

22/2 - Fall 2017, pages 193-218
Date of online publication: 15 October 2018
Date of publication: 15 October 2018

Editor’s Note

The article presents some results of the author’s research carried out within the framework of the project “Neochalcedonian Philosophical Paradigm,” financed by Poland’s National Science Center (grant UMO-2016/22/M/HS1/00170).


The concept of “enhypostaton” was introduced into theological discourse during the sixth-century Christological debates with the aim of justifying the unitary subjectivity of Christ by reclassifying Christ’s human nature as ontically non-independent. The coinage of the term is commonly ascribed to Leontius of Byzantium. Its conceptual content has been recognized by contemporary scholarship as relevant to the core issues of Christology, as well as possessing significance for such philosophical questions as individuation and the nature of individual entityhood. Even so, despite its role in the formation of classical Christological thought, the notion of “enhypostaton” is often regarded as obscure and not clearly defined. This paper aims to shed some light on the meaning of Leontius’ conception of it, in respect of its specifically philosophical import.


Cite this article

Zhyrkova, Anna. “Leontius of Byzantium and the Concept of Enhypostaton: A Critical Re-evaluation.” Forum Philosophicum 22, no. 2 (2017): 193–218. doi:10.5840/forphil201722214.

Full Text

1. Introduction

1The thought of Leontius of Byzantium, an author until recently barely known outside of studies devoted to the Christological debates of the sixth century, has in recent decades received quite significant attention among patristic scholars. I sincerely expect that such attention will only grow, thanks to Father Daley’s tremendous work popularizing Leontius’ legacy through the publication of the first critical edition of his works, together with translations. Such scholars as Daley and Evans were the first to bring Leontius back under the investigative spotlight after a period of oblivion, and they have shown the importance of his teachings for Christology.1 They have also shown the complexity of some elements introduced by Leontius into theological discourse. Among those, one should certainly mention his concept of enhypostaton and his understanding of hypostasis as a subject underlying the union of two natures, such as the union of soul and body in humans, or that of Divine and human natures in Christ. The issue of enhypostaton in Leontius has attracted considerable attention within theological studies, but in spite of its obvious philosophical character has not received analysis from a strictly philosophical perspective. My intention in this paper is to fill this significant lacuna by offering an analysis of the conception from a philosophical point of view.

2Scholars, to be sure, when describing the meaning of the term “ἐνυπόστατον” in Leontius through a Christological lens, have rather boldly presented it as a conception on the basis of which hypostasis could be treated as a principle of individuation, or as something that could serve to elucidate the so-called “in-existence” of being that establishes an individual entity, or as a kind of ontological principle determining the essential qualification of substance.2 Without questioning the value of those ambitious claims, one should attend to the fact that they are not supported by any proper philosophical arguments based on analyses of the conception and terminology employed by Leontius himself. It will hardly suffice to merely point to the presence of some parallels between the philosophical vocabulary used by Leontius and what we encounter in Aristotle’s Categories or Porphyry’s Isagoge, without also seeking to make clear the meaning and role of these philosophical concepts within Leontius’ own thought, or showing whether they are different from their philosophical sources—and, if so, how this affects the philosophical implications of Leontius’ own teaching.

3Indeed, in the Christological works of Leontius, one can find a lot of material of significant value that can and should be examined from a philosophical point of view. Therefore, Leontius’ conception will be analyzed here first and foremost in relation to its ontological and logical significance. The focus, then, will be on giving a proper reading and analysis of his philosophical terminology and concepts, as employed and / or developed by him, with respect to their philosophical import and not just as they relate to, or are useful for, theological discourse.3 Special attention will be paid to relations between Leontius’ account and the Neoplatonic logical commentary tradition, where Leontius’ own close acquaintance with and extensive utilization of the latter is confirmed by his own works.4 All this is necessary because the idea of enhypostaton cannot be removed or distanced from the context of theoretical concern in which it was introduced. In order to explicate it, I must present this context in both of its dimensions: historical and theoretical. These two aspects will be intertwined in my subsequent discussion, as “ἐνυπόστατον” in Leontius expresses the very peculiar manner in which he modifies inherited views on how substance, nature, and hypostasis are related.

4For this reason, the reconstruction of Leontius’ concept of enhypostaton will entail the following steps: after offering a note on the history of the term before Leontius, I will comment on how he understood and related “nature,” “substance,” and “hypostasis,” showing on the one hand where his conception had its roots, and on the other, what problems it inherited. The concept of enhypostaton will be presented as having been introduced through a set of steps that amounted to its precise definition, and which made those problems resolvable. Thus, before discussing the philosophical sense and Christological import of Leontius’ conception, I will need to explain the meanings of the words through which it is presented, including the linguistic connotations of the term on which Leontius relies, while also placing enhypostaton within a set of ontological conceptions he adopts from Neoplatonism.

2. A Historical Note on Enhypostaton before Leontius

5In contrast to the fairly commonly held opinion that it was Leontius who introduced and developed the conception of enhypostaton in Christology, he in fact assumed and further advanced an idea already present and evolving within patristic thought. Since Origen, the term “ἐνυπόστατον” had been in use in theological discourse with mainly two meanings: (1) that of “simple existence” (ἁπλῶς ὕπαρξις), and (2) that of “hypostasis existent according to itself.”5 Moreover, it was in accordance with both of these meanings that it was applied as an ontological characterization to each member of The Holy Trinity and, especially, to Logos in its pre-incarnated stage, where it described their real existence by themselves.

6John Grammarian, however, accepting the term in an already established meaning, enriched it with a new one. He was known as a defender of the Christological doctrine of the unity of two natures in one hypostasis of Christ, proclaimed at the Chalcedon Council, and it was in order to support this doctrine that he introduced into Christology the term “ἐνυπόστατον.” He defined the term as signifying the true presence and existence of a completive constituent element within the structure of independently existent being. In this context, he described substance as enhypostaton—i.e. as an entity that actually exists but does not do so independently (this being an ontological complement of hypostasis, where the latter designates a particular entity of a certain kind).6 As will be shown, Leontius in fact developed a conception already formulated by John Grammarian, giving it an interpretation based on a Neoplatonic reading of the ideas in relation to which enhypostaton had come to be described.

3. Substance, Nature, and Hypostasis in Leontius

7Since, as will be shown later, “ἐνυπόστατον” in Leontius is defined in relation to “substance” / “nature” and “hypostasis,” there is a need to take a closer look at the meaning of those terms. It may seem that Leontius simply followed a tradition, already established in Christological discourse, of synonymic treatment of the members of the pairs of terms “substance”–“nature” and “hypostasis”–“person.”7 Such an understanding is also supported by the no less traditional assumption that the terms “substance” and “nature” denote what is common, while the terms “hypostasis” and “person” designate what is proper.8 All the same, Leontius does seem to differentiate between the precise meanings of those terms.

8To be sure, “substance” was conceived of by Leontius as that which is common to hypostases of the same kind. Hypostases, consequently, were viewed as similar to each other in regard to their substance (CNE IV.148.10–15; Epil. 1.78.22–26). However, substance was also considered in terms of its being the highest genus of the Neoplatonic predication framework:

For definitions of things are predicated synonymously both of [things] of the same genus and of the same species, (as is shown by those who know better [i.e. philosophers]). For if we define substance [taken] in a simple way, we would say that everything that reveals the existence of something shares in the name of substance—and will share also in definition, even if there were myriads of differences between substances. For we say that exist as a substance God, and angel, and human, and animal, and plant; and that the account of substance is attributed to all of them as common, revealing the [fact of their] existence, but not “the what” or “the how” of them. The latter is indicated by proper definition of each thing. That matters are in this way is revealed by the fact that the categories [in the sense of “predications”] are predicated synonymously of coordinated genera. Genera and differences are predicated of species and individuals, for they [i.e. both species and individuals] participate likewise in substance and in life, in corporality and non-corporality, rationality and non-rationality, in sensible and intelligible, and not less in one or more in other, but in the same way and commonly, and—if we refer to them as to a whole—in a definitional way. (Epil. 3.276.28–278.12)

The text quoted above exhibits a significant degree of reliance upon the Neoplatonic treatment of substance. Leontius openly distances his treatment of substance both from an Aristotelian equating of substance with particular essence (τὸ τί), and from treating it as a manner (τὸ πῶς) of being of particulars—i.e. how those particulars are, this being how Gregory had described hypostasis.9 Instead, Leontius proposes to define substance considered “in a simple way” (ἁπλῶς): that is, as such, abstracting from its various possible qualifications. On the one hand, this treatment of substance seems to correspond to Aristotle’s way of describing categories in general, and the category of substance in particular, as what is said without any combination: i.e. just by itself and not in any combination with others in some affirmation or negation (Cat. 1b25–2a10). On the other hand, “substance,” taken in this simple way, is in Leontius’ opinion the name of the existence of a something (ἥ τινος ὕπαρξις), no matter how different such entities might be. It is in that sense that we say that God, angels, humans, etc., exist as substances. Since “substance” points both to existence (τὸ ὑπάρχειν) and to a common account (“κοινῶς … ὁ τῆς οὐσίας ἀποδίδοται λόγος”), there is nothing of which it could be said that it is prevented from falling under a common account of substance. In other words, it possible to conclude that Leontius shares the Neoplatonic account of substance. Substance as such, just as in the Isagoge of Porphyry, appears to be one of the highest genera predicated synonymously of coordinated genera, species, and individuals (Epil. 3.276.28–278.12). The dependence on Neoplatonic doctrine is even more prominent, since Leontius, after having defined substance, immediately and clearly refers to the well-known “Porphyrian tree” of predication, according to which substance as one of the highest genera is predicated of subsequently coordinated genera (such as the corporeal and non-corporeal), the lowest species, and individuals.10 In each case it is predicated synonymically and in a definitional way, so what is corporeal is not more or less substance than an individual horse.

9As something that is predicated of coordinated genera and species, substance can certainly be equated with nature. However, not only does Leontius seem to prefer the term “nature” over that of “substance,” he also uses it to a certain extent in a different meaning.

10While substance, as one of the highest genera, signifying the existence of something, synonymically covers genera and species of entities as well as particular entities, a nature, according to Leontius, does not point to existence by itself, but reveals the ontological completeness (τὸ τέλειον) of an entity. It does not reveal “a given someone,” but rather what “something is made of” (Epil. 8.308.15–20). On the other hand, Leontius states that consubstantial things (τὰ ὁμοούσια), which share a common logos of being (“ὧν ὁ λόγος τοῦ εἶναι κοινός”), are of one nature.11 The logos of being seems to be identical with a definition of substance of a certain kind, which is inevitably characterized by constituents of the substance (τὰ συστατικὰ τῆς οὐσίας) (Epil. 8.308.21–22, 25–27). The constituents of substance are also called by Leontius constitutive differences (αἱ συστατικαὶ διαφοραί) (Epap. 23.342.25–326.5). In accordance with the instances cited by Leontius (e.g., in the case of human beings, their being living, rational, mortal, etc.), constituents of substance or constitutive differences correspond to what is known within Neoplatonic teaching as difference in the most proper sense (ἰδιαίτατα): i.e. specific differences (αἱ εἰδοποιοὶ διαφοραί) that make something different in essence (ἄλλο, Porphyry, Isagoge 8.15–9.2). In Leontius, those constituents of substance, or constitutive differences, also determine the nature of a certain entity. Moreover, Leontius strongly emphasizes that nature is differentiated by its constitutive differences and properties.12 Nature therefore seems to differ from substance construed as one of the highest genera. Yet it corresponds to the narrow notion of substance, identifiable with the lowest species that are completed by constitutive and specific differences (cf. Isagoge 9.2–10.21).

11In Question 5 of CNE, nature is explicated through the relation of the universal to the particular. Claiming that he relies on those who transmitted detailed logical reflections (τὰ λογικὰ σκέμματα), Leontius states that those things that are particular (τὰ ἐπὶ μέρους) exhibit a common sharing in universals, while those that are universal are predicated of particulars.13 Thus, the commonality of individuals (τῶν ἀτόμων κοινωνία) pertains to species in accordance with nature (“ἐστὶ πρὸς τὸ εῖδος κατὰ τὴν φύσιν”), whereas the commonality of universals (τῶν καθόλου κοινωνία) pertains to particulars in accordance with appellation (“πρὸς τὰ μέρη κατὰ τὴν κλῆσιν”), so that a part (τὸ μέρος) can be called by the name of the whole (“τοῦ ὅλου προσηγορίᾳ,” CNE 5.152.15–20). For that reason, when “nature” is said of something, “the meaning of universal and species [τὴν τοῦ καθόλου καὶ εἴδους σημασίαν] is predicated of what is particular and proper” (CNE 5.152.11–14).

12This statement goes far beyond the traditional (in the meaning of that term for Christological discourse) and quite simplistic understanding of nature as what is common. Leontius, relying most probably on the Neoplatonic conception of universals that starts with Porphyry’s Isagoge, presents nature as a common species / form of individual subjects that on the one hand is shared by individuals, while on the other it is also predicated of them.14 A nature is a species in not only the logical but also the ontological sense. It is true eidos / form that is participated in by individuals, and that due to such participation can be predicated of them. To an extent, Leontius differs from the logical approach of the Neoplatonists, as he is more focused on relations between universals and particulars understood as entities than on bare relations between universal appellations and their subjects.

13Nature, construed as indicating a true form / species in an ontological and a logical sense, represents the totality of individuals that share the species in question. This is relevant also in the case of human beings, who are considered to possess two natures: i.e. soul and body. Human nature, just like any other, is one in respect of its species / form (CNE 5.154.1–4). As such, one nature represents the whole human species, as there is no individual that shares the same species / form with some other individuals and is different-in-substance from them. No individual human being can possess a species / form different from universal human nature. For this reason, and seemingly against Gregory’s of Nyssa claims, Leontius states that the particular (τὸ μερικὸν) is rightly referred to through the appellation of what is common (“τῇ τοῦ κοινοῦ προσηγορίᾳ”).15 A particular human, or a particular stone, are truly and completely a human and a stone, and not only partial concretizations of a certain universal nature or substance, which are not substances in their own right.16

14But how did Leontius understand those particulars, i.e. hypostases, of the same species? Such hypostases, on the one hand, were described as similar to each other in regard to their substance (CNE 4.148.10–15; Epil. 1.272.22–26), while on the other as not identical with their nature:

For a hypostasis is also a nature, but a nature is not also a hypostasis: for nature admits of an account of being, while hypostasis also [admits of] an account of being according to itself; and the former [i.e. nature] presents an account of species / form, while the latter [i.e. hypostasis] points to somebody; and the former reveals the character of universal reality, while the latter also sets apart the proper from the common. In brief, “consubstantial” in the strict sense is said of those that are of one nature and whose account of being is common. Whereas the definition of hypostasis is either “those which are identical in respect of nature, but different in respect of number,” or “those that are constituted of different natures, yet have obtained the commonality of being together and mutually in themselves.” (CNE 1.134.5–13)

“Nature” and “hypostasis,” in the opinion of Leontius, should not be taken as having the same meaning. While “nature” is defined as species / form that admits of a common account of being (ὁ τοῦ εἶναι λόγος) and reveals the character of universal reality, hypostasis is described as what allows an account to be given of being according to itself (τὸ καθ᾿ ἑαυτὸ εἶναι),17 in addition to the common account of being. In other words, they do not differ in respect of what they are, i.e. in their essence: a particular horse is not different from the nature of horses, just as a particular human is not different from humanity. For that reason, hypostases of one nature are called consubstantial, as sharing the very same account of being. What nature and hypostasis really differ in respect of is the fact that hypostasis admits of an account of being according to itself, and in that sense reveals not only universal reality, but also a concrete existing entity that shares the same universal account of being. Leontius puts the stress on hypostasis’ being according to itself. It seems that “being according to itself” explains, for Leontius, the fact that hypostasis sets apart what is the proper from what is common, rather than just exhibiting something proper in addition to what is common. Thus, when Leontius subsequently states that the definition of hypostasis is “those which are identical in respect of nature, but different in respect of number,” being “different in number” seems to be a feature of individual entity and not the cause of its individuality. For it is hypostasis that sets apart what is proper. Thus, being different in number and / or being different in virtue of certain characteristics is a consequence of, rather than the reason for, being a hypostasis.

15Leontius also underlines that in contrast to nature, which never reveals existence by itself, hypostasis first of all points to the existence of an entity by itself (τὸ καθ᾿ ἑαυτὸ ὐπάρχον), and only secondarily to its completeness as an entity of a certain nature (Epil. 8.308.13–16). From his discussion with a certain “Acephalus,” who presents a heterodox understanding of the differentiation between natures and hypostases in Christ, it follows that, in Leontius, hypostasis is an entity in actuality. Differences between hypostases are actual (κατ᾿ ἐνέργειαν), in contrast to differences between natures, which are discerned conceptually (κατ᾿ ἐπίνοιαν). Hypostasis, then, primarily conveys the real and actual existence of an entity.18

16Still, there is yet another definition of hypostasis. Seen in the light of this definition, hypostasis is what is constituted of different natures, which have obtained the commonality of being together and mutually in themselves. This definition emerges as Leontius further elucidates the concept of “commonality of being”:

By saying “commonality of being” I do not speak about them [i.e. natures of composed entities] as of complements of their mutual substance, what may be seen in the case of substances and that which is substantially predicated of them, for those are called qualities. But [I speak of] the nature and substance of each of the two as it is not perceived in itself, yet together with the [other nature] compounded and born together with it. One can find also something like this in other things but most easily in the case of the soul and the body, whose hypostasis is common, but each nature is proper, and each account different. (CNE 1.134.13–20)

Leontius does not reduce “the commonality of being” to composition. Natures are not complements of substance, which would reduce them to mere substantial qualities. In the case of such entities as human beings, whom Leontius considers to be compounded of more than one nature, he not only differentiates between the concepts of “substance” and “hypostasis,” but seems to refuse to ontically identify one composite hypostasis with one substance. Human hypostasis is not of one substance / nature. The two natures, corresponding to the soul and the body of a human being respectively, are not seen by him as complements of one human substance. Instead, they are described as compounds of a hypostasis. To be sure, human individuals share in one human nature and do not differ from each other in regard to their essence. In that sense, human nature is common for them. But it is the commonality of a predicated species. In turn, “the commonality of being” pertains to hypostasis that truly is according to itself and whose being is shared by those two different natures. Thus, while hypostasis is unitary and common for compounded natures, each of them remains what it is and preserves its different account. In that case, united natures seem to be ontically dependent beings, distinguishable as regards their account. Leontius states that such natures are distinguished in species / form, but are united in respect of hypostasis (CNE 7.170.3–8). An example of such an ontologically complex entity is certainly and primarily a human, in whom are united two essentially different substances / natures. The hypostasis of a human is a common (κοινή) underlying reality for both of its ontological complements, while each nature is proper (ἰδία) to itself and preserves its own distinct account (CNE 1.134.18–20).19 On the other hand, a hypostasis differs from its complements as the whole is different from its parts (CNE 4.148.10–18). Therefore, it seems that in the case of ontologically complex entities Leontius understands hypostasis not as just a primary substance, but rather as a principle of structure for an individual entity. Moreover, to elucidate hypostasis thus conceived—as a principle of existence and structure for an ontologically complex entity—Leontius introduces the idea of enhypostaton. The very wording of the passage in which this idea is first advanced requires particular attention, as the precise terms to which he recurs need to be well understood with respect to both their meaning and their theoretical background.

4. The Language of the Definition: The Vocabulary and its Connotations

17In the text of the very first question of CNE, in which Leontius introduces the concept of enhypostaton, he elaborates on the conception brought into Christological discourse by his predecessor John Grammarian, introducing nuances that made it possible to transform a germinal idea of substance as enhypostaton into an ontological elucidation of the manner of existence of an essential complement of an individual being. He starts by describing the relationship between hypostasis and substance in terms of being en-hypostasized and in-substantiated:

“Hypostasis” and “enhypostasized” are not the same, just as “substance” and “what is in-substantiated” [ἐνούσιον] differ. “Hypostasis” points to some-one, while “en-hypostasized” [ἐνυπόστατον] points to substance. So, hypostasis sets apart a person through characteristic properties, while the en-hypostasized reveals the fact that it is not an accident, [i.e. something] that has being in something else and is not perceived in itself. Such are all qualities, either those called substantial or additional-to-substantial [ἐπουσιώδης], none of which is a substance that is a subsistent thing, but which are always perceived as somehow related to substance, as color in a body or knowledge in a soul. (CNE 1.132.19–26)

18Before commenting on this text, we definitely need to explain how the key terms have been rendered in this translation, as well as to outline the roots of the philosophical conceptions that stood behind them.

19First of all, the term “ἐνυπόστατον,” from a grammatical point of view, is a regular verbal adjective, from “ἐνυφίσταμαι,” subsist in. It is created from the short form of the verb-stem, visible in the specific case of “ἐνυφίστημι” in the theoretically possible present active plural form, as in “ἐνυφιστᾶσιν.” The standard meaning of verbal adjectives is that of the perfect passive participle. Accordingly, the verbal adjective “γραπτός” can be used to replace the past participle “γεγραμμένος.”20 My translation of “ἐνυπόστατος” as “enhypostasized” tries to preserve a verbal echo in the adjective, as well as to sharpen the difference in meaning between “ἐνυπόστατος,” expressing the idea of “what had / has / will have become hypostasized,” and its frequent translation as “enhypostatic,” which, taken literally, conveys the sense of “having a feature of being in a hypostasis.” The latter sense would rather be spelt out in Greek by the very rare word “ἐνυποστατικός,”21 whose adjectival form suggests merely an en-hypostatic presence of something. The former, on the other hand, adds to this the idea of realization and actuality. The contemporary meaning of the term “ἐνυπόστατος,” as given in both the dictionary of Stamatakos and that of Kriaras and Triandafyllidis, supports such a reading, showing that the term primarily means “that which has hypostasis.”22 Such a rendering is also confirmed by the text, for, as will be scrutinized later, Leontius does not consider accidents, which obviously are in some way in hypostases, as ἐνυπόστατα—i.e. as “what had / has / will have become hypostasized.”23

20In turn, the term “ἐνούσιον” is a regular adjective derived from “ἐνουσιόομαι”, the first connotation of which is “acquiring substance,” while the second is “subsisting in.”24 Therefore, it should rather be rendered as “in-substantial” or “in-substantiated.” The term “ἐνούσιον” is quite rare and does not occur before the third century.25 Inter alia, it can be found in the Medioplatonic author Clement of Alexandria and in Porphyry’s commentary to the Parmenides. To be sure, it was employed after this in a description of Logos, as synonymous with enhypostaton and indicative of real separate existence, by the Cappadocians, Athanasius, and Cyril.26 Yet in Leontius, “ἐνούσιον” is closer to Porphyry’s usage in the text in which he analyses the second hypothesis of Plato’s Parmenides. Porphyry describes there the one (ἕν) as ontically present in substance. Namely, the pure one (ἕν) is an-ousion (ἀνούσιον). In other words, as such it is not substantiated: i.e. does not have a substance of its own. However, the one is in-substantiated (ἐνούσιον εἶναι), participating as it does in substances. The one is not simply in substances as in subjects, though, but rather its being substantiated is presupposed (τὸ ἓν ὑποθείς) in every substance. Thereby it participates in substances. In this way, the one as enousion is a property of any given substance.27

21Another term significant for understanding Leontius’ idea of enhypostaton is “ἐπουσιώδης.” This can be encountered in Alexander of Aphrodisia, but up to the sixth century AD does not occur in anything other than Neoplatonic texts. It was extensively used by David, who is actually dated as coming after Leontius. Yet prior to Leontius it had been well defined in Ammonius. As a matter of fact Ammonius, commenting on Porphyry’s Isagoge, describes as “ἐπουσιώδης” properties that are appropriate for a substance of a certain kind, while essential complements of substance (συμπληρωτικὰ τῆς οὐσίας) of a certain kind are described as “ουσιώδης” (“substantial”). What is epousiodes neither contributes to the essence of a substance, nor destroys it. In speaking of epousiodes, Ammonius seems to have in mind properties of substance as well as accidents.28 In Porphyry, substantial qualities and differentia are described as complements of substance (In Cat. 95, 99), while by “property” he means a certain feature specific to a given species, which is equally predicated of a certain species and interchangeable with what belongs to it, being also equally shared by all members belonging to the species. The accident, though, even when inseparable from its subject (as being black is not separable from being Ethiopian), is neither interchangeable with what belongs to a certain species nor shared equally by all of its members (Isagoge 12.13–13.5, 19.11–15, 22.5–10). Bearing this in mind, it can be assumed that in Ammonius, “substantial” refers to substantial qualities and differentia, while “additional-to-substance” refers either to proper or accidental features of a substance. For example, in the case of a human being its rationality is substantial, while the ability to laugh is its property, and a certain height or color of skin is an accident.

22Since Leontius, speaking about qualities that are not substances by themselves, states that such qualities are called either “οὐσιώδεις” or “ἐπουσιώδεις,” it seems reasonable to assume that he, like Ammonius, differentiates between what is substantial (i.e. adds something to the essence of a substance—like, for instance, rationality in the case of human beings) and what is only additional and characteristic for a substance (such as the ability to laugh, for instance). Therefore, the word “ἐπουσιώδεις” should also be rendered in Leontius in opposition to “οὐσιώδεις,” not as “substantial,” but as “additional-to-substance.” Rendering it as “non-substantial” is most certainly possible and acceptable, but in my opinion tends to emphasize negating its existence rather than conveying the idea of adding something to the substance.29

23Leontius, then, elucidates his concept of “en-hypostasized” through opposing it to hypostasis, while drawing a comparison between “en-hypostasized” and “in-substantiated.” As has previously been shown, Leontius understood substance as such in terms of the Neoplatonic notion of highest genus: i.e. as revealing the existence of something, so everything really existing—whether it is the genus and species of existing entities, or particular entities—receives a common account of substance. However, what is in-substantiated is not something that can in itself and in its own right be considered a substance or a subsistent thing. Instead, it is something always perceived as related to substance. What is significant is that for Leontius, not only are accidents that do not contribute anything to the essence of a substance “in-substantiated,” but also, in the same way, qualities that are substantial are considered by Leontius to be so. It is worth mentioning that in Neoplatonism those substantial qualities (αἱ ποιότητες οὐσιώδεις) were equated with constitutive differences of substance, while the question of their nature and ontological status was one of the most discussed issues within the framework of problems raised by Aristotle’s Categories. A brief presentation of the Neoplatonic discussions concerning substantial qualities that quite probably stand behind Leontius’ treatment of “in-substantiated” would thus seem useful for achieving a proper understanding of his interpretation of the conception of enhypostaton.

5. Theoretical Background of the Definition: Substantial Qualities in Neoplatonism and in Leontius

24The principal motivation for Neoplatonic discussions of the problem of differentia was the fact that Aristotle had not directly discussed the issue of differentiae as such, or that of their categorical status, while the term had been employed in his works quite equivocally: difference on its own appears to be a quality (Metaphysics Δ.14, 1020a33–b17) predicated qualitatively of the genus (Topics IV.6, 128a 26–29). On the other hand, difference as a part of the definition is predicated of a subject in the category of substance (Topics VII.3, 153a15–23). Furthermore, in the Categories, a differentia is described as possessing the same characteristics as substance—in that it is not “in a subject” and is predicated of it univocally (Cat. 5, 3a21–35). The questions, therefore, that Neoplatonic commentators grappled with were (1) whether a differentia is an essential or qualitative feature of its subject, and (2) to which category do differentiae as such belong. However, their interpretation of differentiae was determined using the characteristics of a dominant grouping of them: i.e. differentiae of substance.

25Porphyry, in his Commentary to the Categories, did not provide any definite answer to the question of the ontological status of differentiae, but rather showed two possible solutions to this problem. From one point of view, differentiae can be treated as predicated essentially of species, in relation to secondary substance. As such, a differentia appears to be its essential completive constituent. Therefore, in accordance with Aristotle’s premise that a part of a substance is a substance, as a complement of substance the differentia as such is a substance as well (Porphyry, Isagoge 12.9–11; In Cat. 94.20–95.9, 95.22–34; Simplicius, In Cat. 48.1–34). However, one should remember that in this case we are dealing with predication and the process of definition of species per genus et differentiam. Hence, the interpretation of differentiae as substance is rather a logical solution, proposed for a problem that in itself is ontological in character. In turn, if one takes into account that differentiae display characteristics of both substance and quality, it seems that they participate in both categories. To be sure, as a part of substance, differentiae belong to the category of substance. But the term signifies a substance of a certain kind, and as such is predicated qualitatively (Porphyry, In Cat. 95.17–20).30

26Nonetheless, one can also find a third solution to the problem in Porphyry, as he also claimed that differentiae, like genera and species, are spoken of universally (In Cat. 83.18–19). Hence, as with genera and species, differentiae belong to each of the ten ultimate categories (In Cat. 82.25–28, 83.4–16, 84.4–9). In other words, a differentia does not belong to a category of substance or of quality, but rather each category has its own proper differentiae. Thus, a differentia as such is predicated in any category of which it is proper. Consequently, it is predicated in the category of substance when the subject is considered to be a primary substance. However, in the case of a subject considered as a substance of a certain kind its differentia is predicated in the category of quality. Such an approach to the problem of differentiae appears to be in harmony with that of Aristotle. Indeed, in Topics I.7, 103b20–27, Aristotle distinguishes ten kinds of predication, in which four predicables occur: accident, genus, property and definition.31 These predicables do not belong to any particular category. The category to which they appertain is derived directly from the way of predication. And therefore they can belong to any category whatsoever. Similarly, it seems that a differentia as such is not a kind of being in its own right. Rather, it is a term that can be predicated in every category.32 Though Aristotle did not mention differentiae in his list of predicables which belong to all categories of predication, Porphyry in Isagoge boldly adds the differentia to the four basic Aristotelian predicables.

27Even so, the Neoplatonic inheritors of Porphyry’s thought concentrated rather on the first two of the interpretations of differentia just described. The Athenian Neoplatonic School, through Iamblichus and Dexippus to Simplicius, treated the differentia as an essential quality which, in a sense, is an intermediate between substance and quality.33 Dexippus states that the differentia is of an intermediate state (τὸ μέσον ἕξει) between quality and substance, contributing as it does to “being” (τὸ εἶναι) and also to “being such” (τὸ ποιὸν εἶναι), and is not in a subject.34 On the other hand, according to the Alexandrian tradition initiated by Ammonius and found in Philoponus and David (Elias), differentiae as complements of secondary substance fall into the category of substance.35 According to Ammonius, essential differentiae belong to perceptible substances, which admit of becoming / generation and destruction. Nature combines those differentiae, as substantial, in order to produce, for instance, humans and other composite perceivable substances, such as genera, species and individuals (In Cat. 45.5–48.11; esp. 45.17–20). Ammonius does recognize that while such differentiae as rational and mortal relate to substance (πρὸς τῇ οὐσίᾳ),36 some others relate to accidents (e.g. being black in the case of a raven, or white in the case of a swan), and some are intermediate between substance and accidents, simultaneously participating as they do in substance and quality. Still, he explicitly denies that positing such intermediate differentiae requires the introduction of an eleventh category (In Cat. 46.11–19).

28Obviously, Leontius was not interested in solving, or even merely scrutinizing, the problem of the ontological status of differentiae. And yet, even on the basis of such brief and condensed remarks about substantial qualities it is possible to see that in his account of enousion and epousiodes, while keeping within the Neoplatonic tradition, he shares neither the Athenian nor the Alexandrian solution, but, most probably entirely unintentionally, brings in one of his own.

29To a certain extent Leontius’ understanding of essential quality, in the passage defining enhypostaton, is similar to the position on the question of differentiae described by Dexippus as one of “the solutions of the philosophers of old” (“λύσεις τῶν παλαιῶν φιλοσόφων”). According to this solution a differentia is a quality that is substantial and constitutive of substance (“οὐσιώδη καὶ συμπληρωτικὴν τῆς οὐσίας”) (Dexippus, In Cat. 49.10–11).37 This position is simply tantamount to accepting Porphyry’s definition of differentiae (Porphyry, In Cat. 95.22–31) while ignoring the conclusion that Porphyry himself draws from such a definition: namely, that in that case a differentia will be a substance (In Cat. 95.31–33).38

30In spite of considering substantial qualities to be a completive component of substance, Leontius, in regard to their ontological status, does not view them as different from additional-to-substance qualities. For him, either of these are qualities that differ from substance. While substance exists as πρᾶγμα ὑφεστώς, a really subsistent “thing” or entity, qualities are always perceived in relation to substance. Qualities can be essential for the existence of a substance of a certain kind, as they complete it qua its being such-and-such-a substance. Still, even in that case they are not really existing entities, but ones that always exist as related to substance. In that sense they are in-substantiated (ἐνούσιον), as they do not exist as realities by themselves. Surprisingly enough, the very brief remarks of Leontius concerning substantial qualities contain at least a suggestion for a quite different solution to the question of the ontological status of differentiae. Differentiae (i.e. substantial qualities) are qualities, but not in the sense of accidents. Neither are they substances, nor something intermediate between quality and substance. Leontius describes substantial qualities as in-substantiated: i.e. always participating in substances. Nevertheless, such an interpretation of substantial as well as additional-to-substance qualities was only needed by Leontius in order to properly elucidate his conception of nature as what is en-hypostasized.

6. Reconstructing the Concept of enhypostaton

31What, then, is “en-hypostaton,” if it is said to be comparable to “in-substantiated”? When Leontius’ brief discussion of the subject is placed within the full context of the ideas he merely mentions in that passage, five characteristics of enhypostaton can be seen to emerge from the texts already analyzed here.

  1. Just as what is “in-substantiated” is different from substance, so enhypostaton is different from hypostasis.
     For instance, a particular piece of rock, whose substance can be identified as granite, is different from its in-substantiated complements (quartz, feldspar, and biotite), a combination of which makes up its substance. In turn, its substance of granite can be viewed as what is en-hypostasized in a particular granite rock. The en-hypostasized substance of granite is not therefore ontologically identical with a piece of rock of that kind.

  2. If it is hypostasis that primarily reveals the real and actual existence of a particular entity, then “enhypostaton” cannot refer to a really existent and independent individual being.
     Taking the same example of a certain piece of granite, it is possible to say that “a certain piece of granite” refers to a particular and really existent rock of that kind. On the other hand, “its en-hypostasized granite substance” does not refer to an actually existent rock, but to the very kind of what it is. “En-hypostasized” does not reveal the existence of an individual substance—i.e. “that it really is”—but rather its essential account (or its essential elements)—i.e. “what it is”—
    it being present as it is in individual substances that really exist.

  3. Just as what is “in-substantiated,” even if it is an ontological complement of substance, does not really exist as a separate entity, so what is “en-hypostaton” does not exist as a real entity by itself, but always relates to hypostases, participating and existing in them.
     Here it might seem that the chosen example of a piece of granite will not work, as most certainly the so-called complements of the substance that is granite—i.e. quartz, feldspar, and biotite—do certainly exist as independent and different substances. However, in the substance of granite there are no independent substances of any other kind, but a combination of the minerals mentioned that, due to chemical and structural interactions, constitutes its substance. The example actually shows the exact point of Leontius’ argument: even if a certain kind of being exists as an independent substance, when it serves as one of the essential complements of a different substance it is in-substantiated and not a substance on its own right. What is more, the substance of granite does not exist in abstraction from particular rocks of granite. Quite the opposite: it is always perceived as the substance of a given rock. To be sure, a granite rock is granite in regard to its substance, but its substance does not exist in separation from it. The real entity existing by itself is some given granite rock, the substance of which can only be viewed as a being through intellectual reflection, in reality having its existence in a particular entity.

  4. Since hypostasis is the structuring principle of an individual entity, en-hypostaton is an element belonging to that structure.
     This characteristic is difficult to illustrate using that same example of a granite rock, though it is most applicable to it as well. It is most clearly explained through its exemplification in the form of such a kind of individual entity as a human being. If one accepts that the human individual is a unity of two substances / natures that are different in respect of their accounts, and which, in contrast to those substances that are combined in one new substance of granite, remain discernible and complete in humans, then the ontological import of a hypostasis begins to be self-evident. Hypostasis, as a glass filled with two different liquids, provides for them limits and structure, within which those two liquids can be mixed and subsist as a mixture. Analogously, the hypostasis of a human being is a structure,
    en-hypostasized complements of which are the soul and the body, which are not merely temporarily mixed, but remain different and complete, while completing and constituting an individual human substance.
     Surprisingly, the best example is not an individual being of the human kind, but a creature known as the Atlantic Portuguese man o’ war (
    Physalia physalis). A creature of this kind is not a single multicellular organism, but a colonial organism made up of specialized individual animals called zooids or polyps, which are attached to one another and physiologically integrated, to the extent that they cannot survive independently. As a result, they function like an individual animal. But each individual instance of Physalia physalis is a structure, and not a single substance from the ontological point of view, even though it is treated as one species by biologists. Still, even in the case of a granite rock, though its substance is not ontologically complex, hypostasis is the structure of the individual rock, in which its substance is the en-hypostasized element.

  5. Moreover, that which is enhypostaton does not merely exists in hypostasis, for in that case it would be an accident. In fact, enhypostaton is distinguished from mere accidents as completing and co-constituting hypostasis.
     A granite substance determines a given particular to be what it is in respect of its account and essence. In that sense, it essentially constitutes a particular rock of granite. In a sense it is
    in a particular rock, but not as its size or weight are in it. For neither size nor weight determine what this particular rock is as such.

32The examples shown above pertain to non-complex individual substances as well, even though Leontius only used enhypostaton to explain individuals of a complex kind. This points to the metaphysical potentialities of Leontius’ conception as regards the explanation of individual substances, in spite of the fact that the roots of this conception are logical, and the context theological.

33If we put together all of the above-mentioned characteristics, it is possible to conclude that enhypostaton is a concept posited in order to describe the manner of existence of real beings which, though not individual entities by themselves, do constitute and complete individual entities having an ontologically complex essence. Enhypostaton is an ontological description of a completive constituent of such an independently and actually existent entity. Accordingly, enhypostaton does not exist by itself, but does really exist as a constituent of an individual entity. However, it does not simply exist in an individual entity, as for instance accidental features of a given individual exist in it. Instead, enhypostaton is an ontological element of the structure of an individual entity: it completes and co-constitutes it, so that it can be what it is on its own account.

34If we look into the case through which the concept was developed, we see its far-reaching consequences for the expression of the relationship between how the very same facts of substance are perceived from a logical and a metaphysical point of view. One can define a substance / nature as enhypostaton in the particular case of an ontologically complex being, such as the human individual. As has been already shown, in Leontius, the human individual is considered to be of two different natures: i.e. soul and body. Yet the substance of the human kind is unitary, in the sense of prima species: i.e. τὸ πρῶτον εἶδος. Seen as one substance in terms of form and species, its in-substantiated complements are substantial qualities and differentia (that is rationality, mortality, etc.). Those in-substantiated complements complete this substance so that it can be what it actually is. However, a human being seen as an individual hypostasis appears to be a unity of two natures. A human hypostasis reveals a given human individual that differs by virtue of his or her own characteristics from other human individuals, while the natures corresponding to soul and body are enhypostasized complements of each and every human individual. Soul and body are completive elements, which complete a given hypostasis so that it can be a hypostasis of a human kind. Neither soul nor body exist as individual entities and have a hypostasis of their own. But that does not mean that they do not exist. For they really do exist as constituents of a human hypostasis, receiving their existence in and through their role as its ontological complements.

35Historically speaking, it is possible to say that Leontius “merely” creates a conceptual scheme and a basic tool-box for expressing the paradox conveyed by the Chalcedonian definition, which describes Christ as an ontological unity of two different substances / natures in one hypostasis. In my opinion, while doing this he imparts a factual meaning to a set of interrelated terms (i.e. substance, nature, individual, and hypostasis): he explains what being an ontological constituent of hypostasis actually means, and how such a constituent can exist. What Leontius proposes is a conceptual solution for a paradox that is supposed to work without destroying the paradox. His solution allows the paradox to be expressed consistently, without creating a regress of paradoxes to infinity. But the solution proposed by him exceeded the limits of Christology, and his conceptions had an explanatory power with respect to the Tatsache of individual beings. For his proposals, considered in the light of their implications, lead to a quite different philosophical view of substances. Substance, in the sense of the universal and intelligible species / eidos of an individual being, starts to be treated as an object of explanation, and not the ultimate explicative rationale. But how his intuitions were turned into a theory is a subject for yet another study.


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1 David Beecher Evans, Leontius of Byzantium: An Origenist Christology (Washington: Dumbarton Oaks, 1970); Brian E. Daley, “The Origenism of Leontius of Byzantium,” Journal of Theological Studies 27 (1976), doi:10.1093/jts/xxvii.2.333; Brian E. Daley, “ ‘A Richer Union’: Leontius of Byzantium and the Relationship of Human and Divine in Christ,” Studia Patristica 24 (1993).

2 See respectively Stephan Otto, Person und Subsistenz. Die philosophische Anthropologie des Leontios von Byzanz; ein Beitrag zur Spätantiken Geistesgeschichte (München: Fink, 1968), 38; Benjamin Gleede, The Development of the Term ‘enupostatos’ from Origen to John of Damascus, Supplements to Vigiliae Christianae 113 (Leiden; Boston: Brill, 2012), 64–67, doi:10.1163/9789004227996; Carlo Dell’Osso, “Still on the Concept of Enhypostaton,” Augustinianum 43, no. 1 (2003): 69, doi:10.5840/agstm20034314; Matthias Gockel, “A Dubious Christological Formula? Leontius of Byzantium and the Anhypostasis-enhypostasis Theory,” Journal of Theological Studies 51, no. 2 (2000), doi:10.1093/jts/51.2.515; cf. Uwe Michael Lang, “Anhypostatos-enhypostatos: Church Fathers, Protestant Orthodoxy, and Karl Barth,” Journal of Theological Studies 49 (1998), doi:10.1093/jts/49.2.630.

3 Several times I have met with the criticism that separation of the theological context in the case of the works of such authors as Leontius of Byzantium is simply impossible. To that I must answer that in that case one would have to entirely reject such studies of Christian philosophical thought as those carried out, for instance, by Etienne Gilson. I consider philosophy to be an exploration of rational truth through human cognitive capacities, while, like Gilson, I see Christian philosophy as an exploration of rational truths by human reason that is indebted to the help human reason receives from revelation. The Christian philosopher, besides exploring truth through reason in the light of revelation, can also take into rational consideration and analysis certain theological propositions which he or she believes to be true on the basis of faith and finds lend themselves to being objects of rational exploration. Cf. Etienne Gilson, The Spirit of Mediæval Philosophy, trans. Alfred Howard Campbell Downes (New York: Charles Scribner’s Sons, 1936), 35–36. In a similar manner, an exploration of claims made within theological discourse that treats these as subjects of a strictly philosophical discourse is no less justified, if those claims figure as elements of a rational process of argumentation.

4 Nevertheless, there is still another issue here. In fact, studies of Leontius acknowledging his relation to or dependence on Neoplatonic philosophy mainly take into account just one aspect: namely, the Neoplatonic conception of the unity of the intelligible and the sensible, already studied in detail by Dörrie in the late 1960s. See Heinrich Dörrie, Porphyrios’ Symmikta Zetemata. Ihre Stellung in System und Geschichte des Neuplatonismus, nebst einem Kommentar zu den Fragmenten (München: Beck, 1959). Meanwhile, all other aspects of Neoplatonic thought, and especially its logical tradition of interpreting Aristotle, have been largely undermined or even ignored. Leontius’ thought is not considered in relation to what was actually the mainstream philosophical school of his time, but is linked to an abstraction called “Aristotelianism” instead. That, from a historico-philosophical point of view, is rather anachronistic and methodologically suspicious. See, for instance Dirk Krausmüller, “Making Sense of the Formula of Chalcedon: the Cappadocians and Aristotle in Leontius of Byzantium’s Contra Nestorianos et Eutychianos,” Vigiliae Christianae 65 (2011), doi:10.1163/157007211x561653. Even when authors are demonstrating a general knowledge of Neoplatonism (see Otto, Person und Subsistenz; Gleede, The Development, 64–67), they tend to point merely to terminological similarities, and fail to show how an implementation of the terminology and conception that were thus appropriated shape the content of argumentation employed in theological treatises. They also fall short of demonstrating how, exactly, Leontius or other patristic authors altered the philosophical conceptions appropriated by them. Without all this, such claims as that Leontius, unlike Porphyry and Ammonius, succeeded in solving the problem of individuation (cf. Otto, Person und Subsistenz, 59) can hardly be accepted as substantiated and justified. To be sure, there is one study that may seem to aspire, at least, towards giving a philosophical interpretation of Leontius’ account, Nicholas J. Moutafakis’ “Christology and Its Philosophical Complexities in the Thought of Leontius of Byzantium,” History of Philosophy Quarterly 10, no. 2 (1993): esp. 104–12. However, Moutafakis, who also links Leontius’ conception with Aristotle’s doctrine, does not offer any actual analysis of Leontius’ text, but rather bases his vision of Leontius’ thought on the handbook of Byzantine philosophy by Basil Tatakis, La philosophie Byzantine (Paris: Presses universitaires de France, 1949) and on studies with a predominantly theological focus such as Evans, Leontius of Byzantium, and Herbert M. Relton, A Study in Christology (London: Society for Promoting Christian Knowledge, 1917). He also ignores possible relations between Leontius’ own thought and the philosophical school that existed during his own time.

5 Cf. John Damascene, Dialectica 45.2–7.

6 Anna Zhyrkova, “A Reconstruction of John the Grammarian’s Account of Substance in Terms of Enhypostaton,” Forum Philosophicum 22, no. 1 (2017), doi:10.5840/forphil20172213.

7 Leontius of Byzantium, Contra Nestorianos et Eutychianos (hereafter CNE), I.126.1–2: “Τὸν περὶ ὑποστάσεως καὶ οὐσίας λόγον, ἤγουν προσώπου καὶ φύσεως (ταὐτὸν γὰρ καὶ περὶ ταὐτὸν ἑκάτερα).” Citations of Leontius’ works follow the numbering of the recent edition, Leontius of Byzantium, Complete Works, ed. Brian E. Daley, Oxford Early Christian Texts (Oxford: Oxford University Press, 2017). CNE is printed there on pages 126­–267. However, all translations of Leontius’ texts are mine.

8 Leontius of Byzantium, Epilyseis 3.278.20–23 (ed. Brian E. Daley, in Complete Works, 269–335). Hereafter cited as Epil.

9 Firstly, according to Gregory of Nyssa, hypostases / individuals / persons are real entities, for they are described as enousion (Ad Graecos ex communibus notionibus 21.9–10). However, they are not substances sensu stricto. The substance / nature of hypostases / individuals / persons is only one (Ad Graecos 20.20–24, 21.4–6, 29.9–11). According to Letter 38.3, which was previously ascribed to his brother Basil, substance / nature indicating something common has no standing (στάσις) of its own, but finds such a standing and description due to revealed properties. Hypostases impart to it particular standing and circumstances by virtue of being different numerically and through accidental characteristics (Ad Graecos 30.19–31.20; Ad Ablabium–41.7). As a matter of fact, Gregory holds to a highly Platonic understanding of particular as a collection of qualities. Secondly, in the Trinitarian context of Letter 38, hypostasis is described as a distinctive mark of existence of each person of the Trinity (see 38.6: “ἡ ὑπόστασις τὸ ἰδιάζον τῆς ἑκάστου ὑπάρξεως σημεῖόν ἐστι”). In this sense, it can be interpreted as “how” (the way in which) singular subjects exist. Cf. Polycarp Sherwood, The Earlier Ambigua of Saint Maximus the Confessor and His Refutation of Origenism, Studia Anselmiana, philosophica, theologica 36 (Rome: Orbis Catholicus / Herder, 1955), 157–59.

10 Leontius clearly refers to the well-known “Porphyrian tree” of predication, see Porphyry, Isagoge 4.21–27.

11 See CNE 134.9–10; Leontius of Byzantium, Epaporemata 2.314.7–10 (ed. Brian E. Daley, in Complete Works, 312­–35). Herafter cited as Epap.

12 See Epil. 2.276.14–21, 8.308.30–31; Epap. 22.324.18–24, 23.324.25–326.5, 25.326.21–25.

13 CNE 5.152.15–17, see also 7.168.26–28. One certainly may inquire as to who those mentioned by Leontius were, who passed on such detailed logical reflections. Besides many similarities with Porphyry’s Isagoge, I have found some similarities between Leontius’ text and Ammonius’ Commentary in Isagoge. But all of those similarities can hardly be described as dependence, paraphrase, and quotation. There is only one instance of quite visible similarity between Leontius’ statement “τῇ τοῦ ὅλου προσηγορίᾳ τὸ μέρος καλεῖν” (CNE 5.152.19) and Ammonius’ one: “τὰ γὰρ μέρη, τοῦτ’ ἔστιν αἱ κατηγορίαι, εἰ καὶ τῇ τοῦ ὅλου προσηγορίᾳ προσαγορεύονται” (In Isag. 83.7–8). Yet in fact Ammonius speaks about categories understood as a similar–parts (ὁμοιομερές) in relation to being as such (τὸ ὂν). Nonetheless, the vocabulary and conceptual framework employed by Leontius does point to there being a strong Neoplatonic influence upon him. Ammonius’ text is quoted here and hereafter according to edition Ammonius, In Porphyrii Isagogen sive quinque voces, ed. A. Busse, Commentaria in Aristotelem Graeca 4.3 (Berlin: Reimer, 1891).

14 Leontius clearly identifies “nature” with “species / form.” He states that about one nature (μία φύσις) one can speak in three ways: either as being a species, or as participating in the same species, or as being a species where this is completed by a “con-fusion” of different species that itself participates in them both but is itself neither of them. See CNE 5.154.5–8.

15 See CNE 5.152.20–24. Gregory of Nyssa in Ad Ablabium–15 denies that the name of any universal substance is properly predicated of particulars sharing its essence. The reason for this is that substance / nature is considered by Gregory to be unquestionably one, indivisible monad (μονάς), which does not increase by addition, nor is diminished by subtraction. Substance / nature is one even then it appears in a plurality of items, not being co-divided by the singular ones (καθ’ ἕκαστον) that participate in it. See Ad Ablabium–7; Ad Graecos 20.20–4, 21.4–6, 29.9–11. Hypostases of a certain substance / nature only give it particular standing and circumstances (Ad Ablabium–41.7; Ep. 38.3), and are not substances / natures sensu stricto.

16 I refrain here from discussing the question of so-called “particular natures,” as to do so would exceed the scope of this paper. On this subject, see my upcoming publication on Neochalcedonian ontology.

17 There seems to be an error in the Greek text of the recent edition of Daley, which at 134.6–7 reads “ἡ δὲ ὑπόστασις, καὶ τὸν τοῦ καθ᾿᾿ ἑαυτὸν εῖναι.” The erroneously doubled apostrophe precedes the masculine form of “ἑαυτὸν,” which cannot refer to any masculine noun, as any such are absent from the context. The form, chosen by the editor, replaces the reading “ἑαυτὸ,” present in his earlier manuscript edition, and noted in the critical apparatus. Such a reading probably assumes that hypostasis is by necessity “a someone,” “ὅ τις,” but is inconsistent with what follows. In the next lines, when comparing universal characterization with those pointing to what is proper, Leontius speaks in a more inclusive language of “things,” allowing for all kinds of individuals.

18 See the very interesting text on the difference between διαίρεσις κατ᾿ ἐπίνοιαν and διαίρεσις κατ᾿ ἐνέργειαν, which pertain, respectively, to natures and hypostases, in Epil. 7.288.15–296.16. Leontius underlines that no real distinction between hypostases follows from the conceptual distinction between natures.

19 Here Leontius turns around the Cappadocian distinction between nature as what is common and hypostasis as what is proper.

20 See Herbert Weir Smyth and Gordon M. Messing, Greek Grammar, revised ed. (Cambridge, MA: Harvard University Press, 1984), § 358. Cf. also § 71, § 77.

21 TLG database knows only of one instance in Epiphanius, Panarion 1.271.16.

22 See Iōannes Drakos Stamatakos, Lexikon tēs neas ellēnikēs glōssēs: kathareuousēs kai dēmotikēs kai ek tēs neas ellēnikēs eis tēn archaian, 3 vols. (Athens: Dēmētrakou, 1952–55), s.v; also Emmanouēl Kriaras, Neo Ellēniko lexiko tēs sunchronēs dēmotkēs glōssas, graptēs kai proforikēs (Athens: Ekdōtikē Athēnōn, 1995), s.v; and Idryma Manolē Triantafyllidē, Lexiko tēs koinēs neoellēnikēs (Thessaloniki: Aristoteleio Panepistēmio Thessaloníkēs, 1998), s.v. Two latter entries can be consulted atενυποστατος&sin=all.

23 I would like to mention that I found attempts to render the term “ἐνυπόστατον” through the function of the prefix “ἐν,” and in opposition to “ἀνυπόστατον,” to be insufficient. See Karl-Heinz Uthemann, “Definitionen und Paradigmen in der Rezeption des Dogmas von Chalkedon bis in die Zeit Kaiser Justinians,” in Christus, Kosmos, Diatribe: Themen der frühen Kirche als Beiträge zu einer historischen Theologie, Arbeiten zur Kirchengeschichte 93 (Berlin: De Gruyter, 2005), 80–81, doi:10.1515/9783110891546.37; Gleede, The Development, 11–12. First of all, such renderings are based on only partial analyses of the grammatical form of the term. Secondly, they impose on the author a dictionary-defined meaning without taking into account the philosophical connotations of the term, as well as ignoring the possibility of there being a distinct usage by a particular author.

24 See the entry in the Liddell-Scott-Jones Greek-English Lexicon, 9th ed. (Oxford: Clarendon Press, 1968).

25 In the entire TLG collection it occurs only 195 times, while up to the sixth century it appears no more than 40 times.

26 See my article, Zhyrkova, “A Reconstruction.”

27 See Porphyry, In Platonis Parmenidem commentaria 12.3–10. Cf. Plato, Parmenides 142b–143a, 155e, 163d.

28 See Ammonius, In Isag. 33.16–24: “τούτων οὖν οὕτως ἐχόντων ὅρα πῶς ὁ Πορφύριος κατὰ τάξιν προῆλθε· προέταξε μὲν γὰρ τὰ οὐσιώδη καὶ συμπληρωτικὰ τῆς οὐσίας, ὕστερον δ’ ἔταξε τὰ ἐπεισοδιώδη. καὶ πάλιν τῶν οὐσιωδῶν προέταξε μὲν πρῶτον τὸ γένος ὡς καθολικώτερον, εἶτα τὴν διαφορὰν ὡς τούτου μερικωτέραν, εἶτα τὸ εἶδος ὡς ταύτης μερικώτερον. τῶν δὲ ἐπουσιωδῶν ἐπειδὴ τὸ μὲν ἴδιον πλησιέστερόν ἐστι τῆς οὐσίας, προέταξε μὲν αὐτὸ ὡς καὶ μᾶλλον συγγενέστερον τοῖς εἰρημένοις, τὸ δὲ συμβεβηκὸς τῆς ἐσχάτης τετύχηκε τάξεως ὡς μὴ κοινωνοῦν τοῖς εἰρημένοις καὶ αὐτὸ μόνον γινόμενόν τε καὶ ἀπογινόμενον χωρὶς τῆς τοῦ ὑποκειμένου φθορᾶς.”

29 In any case, “additional to substance” is the first meaning provided by such dictionaries as the Liddell-Scott-Jones Greek-English Lexicon, and Geoffrey W. H. Lampe’s Patristic Greek Lexicon (Oxford: Oxford University Press, 1961–68), for the term.

30 Cf. Frans A. J. de Haas, John Philoponus’ New Definition of Prime Matter: Aspects of Its Background in Neoplatonism and the Ancient Commentary Tradition, Philosophia antiqua 69 (Leiden; New York: Brill, 1997), 224–25, doi:10.1163/9789004320932.

31 See Michael Frede, “Categories in Aristotle,” in Essays in Ancient Philosophy (Minneapolis: University of Minnesota Press, 1987), 29–48.

32 Jacques Brunschwig and Donald Morrison, “Le statut catégoriel des différences dans l’Organon,” Revue philosophique de la France et de l’étranger 183, no. 2 (1993),

33 de Haas, John Philoponus’ New Definition of Prime Matter, 225–26. See Dexippus, In Cat. 48.20–49, 25; Simplicius, In Cat. 98.19–99.12.

34 Dexippus, In Cat. 49.4–5. Simplicius, sharing the same view, attributes it to Iamblichus; see In Cat. 99.3–8.

35 Ammonius, In Cat. 45.5–48.11; Philoponus In Cat. 64.22–67.17; Olympiodorus In Cat. 67.18–35; David (Elias) In Cat. 173.6–174.23.

36 The dative, used here by Ammonius, expresses a relation of close proximity and contact.

37 Dexippus’ text is quoted according to the edition In Aristotelis categorias commentarium, ed. A. Busse, Commentaria in Aristotelem Graeca 4.2 (Berlin: Reimer, 1888).

38 Philoponus, in his turn, did not actually shun the conclusion that differentia, understood as constitutive and completive of substances, ought to be recognized as belonging to the category of substance. See Philoponus, In Cat. 66.6–67.3.