The Metaphysics of Light in the Hexaemeral Literature
From Philo ofAlexandria to Gregory of Nyssa
ISIDOROS C. KATSOS
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Acknowledgements
This book began as a dissertation at the University of Cambridge under the supervision of Rowan Williams. To my PhD supervisor I owe a profound debt of gratitude for teaching me ergoisand logois that philosophy and theology should not be pursued merely as an academic endeavour but should rather be experienced as a way of life. This study is my response to his teaching. I also wish to thank Douglas Hedley for being the internal examiner of my dissertation and for his undiminished support and collaboration over the years, not least through the Cambridge Centre for the Study of Platonism. I am deeply grateful to Paul Kalligas, whose scholarship and mentorship have been fundamental in developing this book. I thank Tom Perridge from OUP and the series editors Gillian Clark and Andrew Louth for generously accepting the book for publication in the Oxford Early Christian Studies series. Andrew Louth has guided the publication of this book with wise and deeply encouraging advice. I am also grateful to the two anonymous readers, whose comments greatly improved the final manuscript. Christian Hengstermann has been an ideal friend and collaborator since our Cambridge time together. I thank him for reading the manuscript thoroughly and giving me precious feedback. I also thank Rachel Evan Webb, Henry Clarke, and the editorial team of OUP for their tremendous editorial assistance, together with Artur Suski and Konstantina Morou for their help in compiling the Indexes of Persons and Passages.
I also wish to express my gratitude to Oded Irshai, the Director of the Center for the Study of Christianity at the Hebrew University of Jerusalem, and my colleagues at the Center, especially Guy Stroumsa, David Satran, Brouria Bitton-Ashkelony, Yonathan Moss,
David Lloyd Dusenbury, and Francesco Celia, for their tremendous friendship and support. My Postdoctoral Fellowship at the Center made possible the turning of the dissertation into a book manuscript. I am also indebted to Diana Lipton and Chaim Milikowski for opening up their hearts and home, initiating me into the richness and warmth of Jewish hospitality. Last but not least, I am grateful to the Fellowship and Community of Campion Hall (Oxford) for their friendship and support during the editing phase of this book.
The initial dissertation was made possible due to generous funding from the British Arts and Humanities Research Council, Pembroke College (Cambridge), the George and Marie Vergottis Foundation, the Theological Studies Fund at the Faculty of Divinity (Cambridge), the Leventis Foundation, and the Church of Greece. My gratitude to them is hereby acknowledged. A preliminary version of the argument of this book is published in ISIS110/2 (2019), 270–82 (https://doi.org/10.1086/703515). I thank Floris Cohen, who as journal editor encouraged its publication and the public discussion that followed; and the History of Science Society for the kind permission to use some of the material in this book. I also wish to show my appreciation to Brill publishers for the kind permission to use the following translated quotations as epigraphs: in ‘Conclusions’, a quotation from Frederick W. Norris (ed.), Lionel Wickham and Frederick Williams (tr.), Faith Gives Fullness to Reasoning: The Five Theological Orations of Gregory Nazianzen (Leiden: Brill, 1991); in ‘Appendix B’, a quotation from David Runia, Philo of Alexandria: On the Creation of the Cosmos According to Moses(Leiden: Brill, 2001).
Finally, I owe my gratitude to His Beatitude Archbishop Hieronymus II of Athens and All Greece for his constant encouragement and support of my academic pursuits. Without his personal blessings, none of this would have been possible. Similarly, I am deeply grateful to His All Holiness Ecumenical Patriarch Bartholomew for his permission to continue my liturgical duties while working academically in Cambridge and Oxford; and to His Beatitude Patriarch Theophilus III of Jerusalem for his Abrahamic hospitality
during my stay in Jerusalem. This book is dedicated to Metropolitan Bartholomew of Polyanni and Kilkis, who has been my lifelong spiritual guide.
Contents
ListofAbbreviations
Introduction
0.1 0.2 0.3
What Do We Mean When We Speak of the ‘Metaphysics of Light’?
What This Book Aims to Achieve
Old Wine in New Skins: From Light Language to the Concept of Light
0.3.1
0.3.2
0.3.3
1.
2.
Boyancé’s Challenge
A Challenge Still Not Met
The Need for a Fresh Start
‘From Sight to Light’: A Hexaemeral Guide for the Perplexed
The Intelligibility of Hexaemeral Light
The Oculocentric Thesis
Three Arguments for Oculocentrism in the Hexaemeral Literature
Sight Fantastic
A World with a View
A Christocentric Vision of Creation
Rethinking Oculocentrism
Narrowing down the Scope
Sight Is Light
From the Phenomenal to the Noumenal
The Light of the World: Hexaemeral Physics and Anti-Physics
Science at the Service of Scripture
In Defence of Hexaemeral Physics
Origen and His Legacy
Introducing Gregory’s Apology
Approaching Nature through the Lens of Scripture: Physics as Hermeneutics
Enter Light
A Look behind the Scenes: The Hexaemeral Theory of Change
A (Meta-)Physics of Power Causality: The Consubstantiality of Fire and Light
The Nature of Light: The Dawn of the First Material Form
Between Physics and Metaphysics: The ‘Immateriality’ of Light
Scriptural Questions
Philosophical Investigations
Cappadocian Answers
Hexaemeral Physics
Hexaemeral Hermeneutics
Going Ballistic: The Singularity of the Light Ray
Rectilinearity
Light Mechanics
Light Kinetics
The Speed of Light
Introducing Field Theory
The Metaxuof Light: A Metaphysical Note on the Medium A Medium of Light?
Transparency and Brightness
Light Semantics as Key to Light Hermeneutics
The Metaphysics of Light: A Hermeneutical Coda
A Dual Aspect Interpretation
3.4.2 3.4.3
Conclusions
Appendices
A.
B. C.
Back to Origen
Philonic Beginnings
Response to a Critic, or What Is the History of Optics Really About?
What Is the Colour of Light?
‘Light from Light’, or What Is the Meaning of Doxaand Apaugasma?
Bibliography
I. II.
CriticalEditionsofAncientWorksCited
SecondaryBibliography
IndexofPassages
IndexofPersonsandNames
SubjectIndex
Glossary
List of Abbreviations
Abbreviations of works cited are given in the bibliography. General abbreviations follow the standard bibliographical practice. Common abbreviations in this work are:
Die Griechischen Christlichen Schriftsteller der ersten Jahrhunderte
GNO
SC
GregoriiNysseniOpera
Sources Chrétiennes
Now intellect discovers the duality, because it divides until it arrives at something simple that cannot be analysed further; as long as it can it proceeds to the depth. And the depth of each thing is matter; this is the reason why matter is entirely dark, for the light is the form.
Plotinus, Enn. (12) II.4.5
Introduction
The first corporeal form which some call corporeity is in my opinion light.
(Grosseteste, De Luce, tr. Riedl)
0.1 What Do We Mean When We Speak of the ‘Metaphysics of Light’?
There are few terms that belong to the trade secrets of both philosophers and theologians. The ‘metaphysics of light’ is one of them. The term has been linked to Parmenides, Plato, Philo, Plotinus, Augustine, the Areopagite, Grosseteste, Bacon, Eckhart, Cuzanus, and Ficino. And this is just the short list.1 The theme of light has brought scientists, historians, philosophers, and theologians to the same table and made them talk.2 Light symbolism has become a codeword for the Western ‘mystical tradition’, however defined, giving it a sense of orientation, continuity, and tradition.3 Behind the popularity lies a revived interest in medieval light speculation, climaxing in a fascination with Grosseteste’s thought.4 Every fascination, however, comes at a price. The references to the ‘metaphysics of light’ are currently so diverse and prolific that they have nurtured a devalued and exploded term. As David Lindberg once put it:
There has been much discussion of Grosseteste’s ‘metaphysics of light’ (for which I prefer to substitute the expression ‘philosophy of light’, since much of it has nothing to do with metaphysics), but this discussion has frequently
suffered from a failure to make several indispensable distinctions among differing bodies of ideas. Within Grosseteste’s philosophy of light, there are at least four distinct strands, each employing optical analogies and metaphors: (1) the epistemology of light, in which the process of acquiring knowledge of unchanging Platonic forms is considered analogous to corporeal vision through the eye; (2) the metaphysics or cosmogony of light, in which light is regarded as the first corporeal form and the material world as the product of the self-propagation of a primeval point of light; (3) the etiology or physics of light, according to which all causation in the material world operates on the analogy of the radiation of light; and (4) the theology of light, which employs light metaphors to elucidate theological truths.5
Lindberg’s exposition shows why so many disciplines feel attracted to the ‘metaphysics of light’, yet so little interdisciplinary consensus has been achieved, meanwhile, as to how to understand the term. In order to regain its focal meaning, we need to resist the tide, retrace our steps, and go back to where it all began. The great medievalist James McEvoy shows us the way:
The term ‘metaphysics of light’ was coined by Clemens Baeumker in 1916 and has been employed widely, though not uncontroversially, ever since. It designates a whole circle of themes, a current of philosophical and religious thought that runs right through European culture from ancient times down to the Renaissance.6
Baeumker introduced the term Lichtmetaphysik over a century ago in an epoch-making study on the anonymous Liber de intelligentiis, which he then attributed to the medieval thinker Witelo.7 Baeumker spoke of ‘metaphysics of light’ to denote, very generally, the identification of the intelligible world with light. And since God was theorized in the De intelligentiis as the first principle of every intelligent nature, and every intelligent nature was identified with light, the ‘metaphysics of light’ ultimately denoted the identification of God, qua ontological foundation of reality, with some kind of primordial light. In specifying what that kind of light might be, Baeumker distinguished three ontological models and respective modes of language:8
•
•
A transcendental model, according to which the divine is ‘light’ metaphorically speaking. ‘Light’ functions here merely as a façon deparler, one of many possible ways of speaking about God, who by his very nature exceeds the limits of human thought and language. Baeumker’s examples included Plato’s celebrated light images from the central books of the Republic, the so-called ‘sun simile’ (VI 507a–509c) and the ‘allegory of the cave’ (VII 514a–520d).
• An immanentist model, according to which the divine is light properly speaking, as part of a physicalist metaphysical universe, in which God is identified with cosmic light or fire. The examples that Baeumker used include the Brahman of the Upanishads, the Heraclitean/Stoic cosmic fire, Manichean light, and, more generally, the astral deities of the Hellenistic cosmic religion.
A mixed model (of combined transcendence and immanence), building on a metaphysics of mediation or participation. The participatory metaphysics of this model entailed a unified and continuous notion of ‘light’, of which sensible light and intelligible light were the two extremes. Like the physicalist (first) model, the divine is here, too, light properly speaking. But unlike the physicalist model, divine light is now the transcendent intelligible archetype, of which every materialphysical light is the sensible copy. Baeumker saw the beginnings of this model in Philo of Alexandria and its full articulation in later Platonism, especially in the works of Plotinus and Proclus, before it acquired its highest peak in medieval scholastic philosophy, most notably in the De intelligentiis.
The metaphysical universe of Baeumker’s third model was, admittedly, ‘Neoplatonic’ and its light language ‘analogical’. The kind of analogy that Baeumker had in mind was the scholastic variant of the ‘analogy of attribution’ (per prius et posterius).9 In this view, ‘divine light’ was not a mere figure of speech but light properly
speaking. The intelligible world was truly light (prior or original sense), while the light of the senses (like the light of the sun, the moon etc.) could only be called ‘light’ in virtue of a relation of participation to an intelligible archetype (posterior or derivative sense). As regards Christian thinkers, Baeumker’s position was ambivalent, making three incongruent claims: first, the authors of the New Testament and early Christian thinkers spoke of God as light only metaphorically. Second, post-Nicene theologians deviated from the original tradition by introducing the ‘Neoplatonic’ participatory metaphysics and its corresponding analogical language to denote the emanation of divine light to the world. As regards the transcendent divine essence and the persons of the Trinity, however, post-Nicene theologians retained the originally ‘Platonic’ metaphorical light language of the original tradition of the early Church. Implicit in this scheme was the distinction between ‘theology’ and ‘economy’ or ad intra and ad extra of God, to which Baeumker correlated the metaphorical and the analogical use of light language, respectively. The main protagonists of this binary use of language were, for Baeumker, Gregory Nazianzen and Dionysius the Areopagite in the Greek patristic tradition and Augustine and his school in the Latin tradition. Third, Aquinas criticized the Augustinian tradition for being closer to Neoplatonism than Scripture, since the scriptural language of God as ‘light’ (and of Christ as ‘true light’) had to be, under Thomas’s Aristotelian premises, metaphorical. Baeumker also warned the reader that the distinction between the three models can be hard to make, while the classification of a particular author or text as following this or that model can easily become contentious.
Baeumker’s thesis would have probably remained a minor incident in the history of Western scholarship, had it not touched upon a sensitive chord. Throughout the twentieth century, continental scholars debated explicitly or implicitly, but always passionately and inconclusively, about Baeumker’s classification and model attribution. Two examples amply show how a whole century of light dialectics led to the current standstill. Giles Wetter was an early defendant of the physicalist model, which he used for the interpretation of light
imagery in Hellenistic religious thought, especially the mystery cults.10 The response came almost half a century later from FranzNorbert Klein, who, in a special monograph, argued for the contrary position, based on the writings of Philo of Alexandria and the Hermetic Corpus. Yet Klein remained enigmatic as regards his own interpretation of Philo: on the one hand, he observed the compresence of Baeumker’s transcendental and participatory ontological models in the Philonic corpus; on the other hand, he insisted that, in spite of the participatory metaphysics and in view of divine transcendence, the Philonic language of God as light had to be metaphorical.11 Another famous episode in the hundred years’ war over the premodern light hermeneutics was the debate between Werner Beierwaltes and Rein Ferwerda, this time with Plotinus as the apple of discord. Beierwaltes dedicated his life’s work to the refinement and further development of Baeumker’s thesis, becoming the leading expounder of the ‘metaphysics of light’ in the second half of the twentieth century.12 For Beierwaltes it was only the participatory model that gave rise to a proper ‘light metaphysics’ (Lichtmetaphysik), while the transcendental model allowed merely the generation of light metaphors (Lichtmetaphorik). From his doctoral thesis to his erudite studies on Plotinus and Proclus, Beierwaltes defended the participatory ‘metaphysics of light’ as the distinctive characteristic of the Platonic tradition: true being was intelligible being and intelligible being was light properly speaking, while physical light was so only in virtue of its participation in its intelligible archetype. The names belonging to this tradition make up a long list, including Pythagoras and Parmenides as forerunners; Plato as the founder; and two lines of succession, through which the ‘metaphysics of light’ came to flourish: Plotinus and Proclus on the one hand, Philo and the Church Fathers, especially Augustine and Dionysius the Areopagite, on the other.13 Beierwaltes’s interpretation of Plotinian light imagery caused the emphatic reaction of Ferwerda, who argued that the dualistic premises of Platonic orthodoxy, of which Plotinus was a true disciple, necessitated a radical gap between the intelligible and the sensible realms. Such discontinuity
precluded the possibility of any analogical language of light. Consequently, Plotinus’ use of light imagery in speaking about the higher realities was purely pedagogical, hence metaphorical, while Beierwaltes’s participatory ‘light metaphysics’ was an anachronistic eisegesis of the medieval theory of analogy, inspired by Baeumker and projected back onto ancient sources.14 Ferwerda’s argument may have shaken (though not destroyed) the credibility of Beierwaltes’s thesis as regards Plotinian scholarship.15 But it only helped reinforce Beierwaltes’s interpretation as regards the Augustinian tradition throughout the Middle Ages. Anyone interested in the analogical talk of God as light (and an alternative to Thomist Lichtmetaphorik) had only to look here for a safe heaven.16 Hence the fascination, in English scholarship, with Grosseteste under the borrowed label of the ‘metaphysics of light’.
Clearly, there is something elusive in a debate that lasts over a century without reaching a conclusive result. A careful study of the major protagonists reveals a subtle but crucial detail. The recurring question in the aforementioned literature has not been the interpretation of Philo, Plotinus, Augustine, Dionysius, or Grosseteste as such. The real issue has been how these thinkers interpreted another text, namely Plato’s ‘sun-simile’ (together with the adjacent images of the ‘divided line’ and the ‘cave’), and its reception history. The real debate, then, has been about the history of interpretation of the Platonic light language. If we now go back to the original source, it is easy to see that the Platonic text is itself responsible for its ambivalent reception through the centuries. In his speech to Glaucon, Socrates introduces the sun as an analogon of the Good (tagathon), in the sense that ‘whatever the Good is in the intelligible realm, in relation to the intellect and intelligible things, the same is the sun in the visible realm, in relation to sight and visible things’ (508b13–c2). Socrates then goes on to explain the analogy in terms of a simile (hōsper…houtōi509a1–5) but he also says that the sun is the image (eikona) of the Good (509a9), exhibiting a relation of similarity (homoiotēta) to it (509c6). The perennial question in Western light hermeneutics has been, precisely, the meaning of the
sun as an analogon of the Good. The constant challenge has been how to disentangle two different senses of ‘analogy’, analogy of language and analogy of being. Behind the distinction hides one of the most fascinating questions in the history of Western philosophy: the relation between being and language. For instance, if one were to approach the analogy of the sun as a solution to the paradox of talking meaningfully from within language about the Good that lies ‘beyond being’ (epekeina tēs ousias), and thus beyond the predicative ability of human language, one would have to take seriously the hōsper (‘just like’) clause and conclude that Plato’s celebrated light imagery (or any other light imagery with a transcendent referent) is a clear-cut case of figurative speech, a veritable similein the sense of the classical theory of metaphor.17 If one were to approach the analogy of the sun, however, as an illustration of Platonic participatory metaphysics (‘theory of forms’), one would need to take seriously the predicative function of the Platonic ‘image’ (eikōn) as a type–token relation that links causally different modes of being and conclude that the sun is the sensible copy of a supra-intelligible archetype that Plato calls ‘the Good’. Even though Plato’s light imagery—in its effort to express through language what escapes ordinary language—remains a simile, the sensible object that functions as the ground of the simile (i.e. the sun) is itself causally dependent on the semantic target that it aims to explain (i.e. the Good). In other words, in Plato’s metaphysical universe the sun does not merely illustrate, as a figure of speech, the function of the Good. The sun is what it is, irrespective of any simile, because of the Good. As G.E.R. Lloyd puts it in his monumental study Polarity and Analogy, not all types of Platonic ‘metaphors’ are empty figures of speech.18 The ‘sun simile’ contains an analogical argument as ‘an important means not merely of instructing the pupil, but also of discovering and intuiting the truth’.19 It is one of those ‘true and significant analogies’, which are ‘not a mere coincidence, but rather, it seems, the result of a sort of divine guidance’.20 With these thoughts in mind, and after a century of debates, it is possible to draw an irenic conclusion. The
‘metaphysics of light’ is a term with a precise reference (the talk of the divine as ‘light’) and an elusive meaning. Its elusiveness is the result of the peculiar mixture of metaphorical language with participatory metaphysics in the central books of Plato’s Republic. Much of Western light imagery can be traced back to this text.21 To this extent, the quest for the ‘metaphysics of light’ is the quest for the role and meaning of Platonic metaphysics in the Western intellectual tradition.
0.2 What This Book Aims to Achieve
The aim of this book is not to rehearse the intellectual history of light imagery in Western thought, nor the history of Platonic metaphysics; neither does this book aim to explore the reception history of Plato’s ‘sun simile’; nor to revisit the question of metaphor and analogy. This book has the modest aspiration of revisiting only a tiny part of the intellectual tradition that has been classified under this or that model of the ‘metaphysics of light’, namely the JewishChristian metaphysical tradition of the early Church, and then again only one episode in the context of this tradition, which is, as we know today, extremely rich and diverse in its expressions. The episode I have in mind focuses on the so-called ‘Alexandrian tradition’ and its Cappadocian interpretation, and has Philo of Alexandria, Origen, Basil of Caesarea, and Gregory of Nyssa as its main protagonists. There are a few significant reasons for this choice. As we have already seen, Philo is the point of contention between Baeumker or Beierwaltes, who place him at the head of the participatory metaphysics of later Platonism and its analogical light language, and Klein, who pushes the point that metaphorical language is the only one adequate to express absolute divine transcendence. At the same time, Philo is at the head of a metaphysical tradition, which, through the catechetical school of Alexandria, reached down to Origen and, through an Origenian line of transmission via Gregory Thaumaturgus and Macrina the Older, became a major source of inspiration for the Cappadocian school of thought.22 Philo, Origen, and the Cappadocians exercised tremendous influence in the history of early Christian thought. In the West, they were the great sources of inspiration for Ambrose, who initiated Augustine into the deeper meaning of Scripture.23 Similarly, in the East, the unknown Syrian author writing at the turn of the fifth and sixth centuries under the literary name of Dionysius the
Areopagite is highly indebted to the Alexandrian and the Cappadocian schools for his doctrine of illumination.24 But it is the short treatise on Mystical Theology, with its celebrated imagery of ‘divine darkness’, that has contributed most to the author’s legacy as the mystical theologian par excellence. The treatise is based on the theme of Moses’ mystical ascent, which the author could not have developed in this way were he not deeply acquainted with the works of Philo and Nyssen on the Life of Moses.25 In drawing a line of succession from Philo to Gregory, I aim to investigate the formative period of the Christian ‘metaphysics of light’, so much so that my three main protagonists, namely Origen, Basil, and Gregory, have been, strikingly, entirely neglected by the previous discussion. In bringing them into focus, I aim to fill in a gap in current scholarship. In doing so, some of what we thought we knew about late antique ‘light metaphysics’ might shine under a different light.
0.3 Old Wine in New Skins: From Light Language to the Concept of Light
0.3.1 Boyancé’s Challenge
In his review of Klein’s monograph, the French classicist Pierre Boyancé remarked that Klein had neglected to take into account the physical theories that supported and further explained Philo’s light metaphors and ‘light metaphysics’.26 Take, as an example, the case of a purely metaphorical use of language. Boyancé argued that, according to the classical metaphor theory, the structure of a simile consists of the transfer of meaning (i.e. of a semantic property) from a source domain to a target domain, establishing a relation of similarity between the two. In the case of light metaphors, the source domain is physical light and the target domain is an intelligible agent or object (like the divine intellect or the intelligible
world). In order to understand the meaning of ‘light’ as divine predicate in Philo and the philosophical literature he represents, we need to know which properties of light the author had in mind in each particular context. This requires an investigation into the physics of light that explained these properties. Boyancé rightly complained that Klein never conducted such an investigation. His was a serious accusation. If it is true that the Philonic use of light imagery is entirely metaphorical, as Klein argued, it is especially dire that Klein’s research never investigated the ground of meaning of Philo’s light language. Boyancé’s complaint can be generalized. With few notable exceptions, the debate on the ‘metaphysics of light’ did not touch upon the physical theories that ground the meaning of the language of God as light.27
One might retort that Boyancé’s objection applies only to the metaphorical interpretation of light images (Lichtmetaphorik). It does not apply, however, to their analogical interpretation (Lichtmetaphysik), according to which there is no transference of meaning from the physical world to the divine reality. The followers of the latter interpretation might feel that Boyancé’s critique misses the mark, since, on this reading of the sources, the language of divine light is logically prior to the language of physical light, in the sense that the term ‘light’ has its proper and primary significance with reference to God.28 This is an important point that modern scholars think was also advocated by pro-Nicene theologians, such as Athanasius, Basil, and Gregory of Nyssa.29 If so, the heroes of the Nicene faith would be major exponents of the Christian ‘metaphysics of light’ in its analogical interpretation. Nevertheless, it is a moot point. We have no clue what divine predicates such as ‘light’ (or ‘father’, ‘creator’ etc.) might mean if we do not start from familiar semantic contexts in which the words already have meaning. That is precisely the point of the Platonic analogy of the sun, whose aim it is to help the reader intuit something of the unfamiliar meaning of goodness itself (auto agathon 507b; epekeina tēs ousias 509b) by comparison to something known to the senses and a commonly shared experience of goodness. The analogy of the sun proposes, as
such, an experience of the self-communicating nature of heavenly fire, which illuminates the earth through its light and sustains life through its warmth. The ‘metaphysician of light’ may here retort that the philosopher who has attained direct contemplation of goodness itself has no need for analogical reasoning, apart from pedagogical purposes. The same is true for the scriptural equivalent of the Platonic philosophical vision, whether in the sense of Moses’ theophanic experience of the burning bush on Mount Sinai or in the sense of the disciples’ mystical experience of the light of transfiguration on Mount Tabor.30 Yet to understand the language of divine light only by direct theophanic knowledge is an extremely high bar for the average scriptural (or Platonic) reader who has not yet attained that experience and genuinely wants to learn about it. Indirect knowledge is necessary if divine predicates are to make sense in the first instance.31 Such indirect knowledge can only be derived from experience known and familiar to the reader, i.e. in the case of light, from the reader’s acquaintance with the light of this world. It thus makes no difference whether we understand ‘light’ as divine predicate in a figurative (Lichtmetaphorik) or non-figurative sense (Lichtmetaphysik). In both senses, we need to unpack the meaning of the concept starting from our experience of physical light. To give a celebrated example of an early Christian use of light as divine predicate, think of the Nicene formula ‘light from light’: no matter how we understand its mode of language (figurative or proper), we still need to ground its meaning in the world of our direct and immediate knowledge. How does light generate light in the physical world? What are the physicalproperties of light that are theologically relevant? Boyancé’s objection holds regardless of the mode of language used in the sources. There is still a dire need to investigate the conceptofphysicallightin early Christian literature.32
0.3.2 A Challenge Still Not Met
The lack of interest in the early Christian theories of light is most evident in the camp of Lichtmetaphorik.33 Studies which consider the light imagery to be more than a mere metaphor investigate further the ground of the analogical reasoning from light.34 Yet they too forgo a systematic investigation of the early Christian physics of light, extrapolating some physical properties of light from the theological debates rather than examining the validity of the theological arguments invoked in the debates according to the physical properties of light that ground them.
The lack of a thorough discussion of the ancient physics of light is also characteristic of a cluster of four seminal studies on the theological use of light language by the Cappadocians.35 They significantly advance our understanding of the early Christian concept of light by showing that it is a physical power, which is logically construed as a proprium (see Chapter 2, section 2.3.2). If we ask, however, ‘physical power of what?’ or ‘proprium of what?’, the answer we get from these studies becomes blurry. In his landmark PhD dissertation on the notion of power in Gregory of Nyssa, Michel René Barnes at least once regards light, incisively, as a property of fire.36 The recurring argument of the book, however, is that light for the Cappadocians is an example of power causality in which a cause reproduces itself (or its nature). Barnes thus treats the cause of light as being itself light ‘in exactly the same sense’ as its effect.37 Although the premise is correct, it will be shown that Barnes’s conclusion is ultimately misleading: light as cause and light as effect do not have the same reference in ancient physics and that has direct consequences for the theological light language (see Chapter 3, section 3.3.3 and Appendix C). Something similar can be said about the brilliant studies of Andrew Radde-Gallwitz and Mark DelCogliano, which show that light as an inherent physical power is logically construed as a proprium. DelCogliano does not specify the physical substance of which light is a proprium. In general, he follows Barnes’s univocal interpretation of light in Basil’s writings38 and seems at least once as bewildered as Barnes by Eunomius’ (actually correct) claim that light as cause and effect does not
denote exactly the same thing.39 Radde-Gallwitz goes a step further in the right direction. In his monograph he mentions, correctly, that light is the inherent power of fire40 but then goes on to construe, misleadingly, ‘light’ together with other divine predicates such as ‘life’ and ‘goodness’ as ‘analogous to the propria of the elements’.41 He thus follows Barnes in considering heat (instead of heat andlight) as the typical proprium of elemental fire.42 Similarly, in a seminal paper which further discusses light as a power and property in Basil’s Hexaemeron, he identifies, again correctly, light as a power and property of the sun,43 but then goes on to distinguish the properties and powers of elemental substances from light as a property and power of the sun,44 instead of regarding the sun as a particular instance of (elemental) heavenly fire. The aforementioned studies contribute only partially to decoding the meaning of (physical) light in early Christian literature, either because they identify the cause of light with its effect or because they identify light with a natural power or proprium without specifying adequately the source of light as power or proprium. In fact, this book will argue that the meaning of ‘light’ in early Christian literature is richer than that.
In an influential study, Volker Henning Drecoll shows some traces of reflection on the Christian physics of light.45 His claim that ‘light’ is a suitable theological predicate because of its ‘immateriality’46 builds on a textually verifiable premise, which, however, does not mean immateriality in an ontological sense, as will be shown in Chapter 3. In a fascinating footnote, Drecoll alludes to precisely that (i.e. ‘light’, like pneuma, denotes ‘a finer substance’) but then, mistakenly, claims that in Basil ‘no clear distinction is carried out between the divine and the physical light’.47 Finally, the paper of Adrian Marinescu is a valiant effort to enquire into Basil’s concept of light, but it unfortunately remains at a superficial level.48
Thus, there is only one study that, to my knowledge, answers Boyancé’s objection from an early Christian perspective. In his remarkable book on the use of philosophy in early Christian theology, Christopher Stead unpacks the theological language of
light in constant reference to ancient physics, most notably the Platonic and Stoic physics of fire and light.49 But his is a book of heights and falls. The book offers only occasional, though valuable, remarks.50 Crucially, the analysis is not always sound: as will be shown in Chapter 3, Stead’s assumption that fire in early Christian physics ‘need not involve combustion’ is false and so is his conclusion that fire was ‘an appropriate symbol for the divine nature, in that one can ignore its dependence on an exhaustible supply of fuel’.51 His assumption that in early Christian physics all material substances are composite is correct, but his conclusion that light cannot serve as a paradigm of simplicity is not.52 Last but not least, Stead shows an outspoken distrust in the cogency of early Christian philosophical analysis, leading to a somewhat biased assessment of the early Christian theology of light.53
0.3.3 The Need for a Fresh Start
This book begins with the basic assumption that the concept of physical light grounds the referential meaning and semantic context of the theological language of light in early Christian literature. To achieve its goal, this book remains intentionally agnostic as regards the mode (literal, analogical, or metaphorical) of the theological light language. Its aim is to shift focus from the language to its referent, from the sign to the signified, from ‘light’ as a divine predicate to the concept of light itself. In doing so, this book understands the quest for the ‘metaphysics of light’ differently than before. It is no longer interested in classical dilemmas of the sort ‘literal or metaphorical’, ‘figurative or non-figurative’, ‘proper or improper’ etc., which have been the focus of the ‘linguistic turn’ of the twentieth century and which have widely monopolized previous discussions. That is not to say that these are not still interesting and important questions to ask.54 It is only to say that, unless we ask the logically prior question, there is little room left for novel contributions in this
regard.55 The logically prior question, which ancient readers had to ask before they decided how to read the scriptural references to light, literally or metaphorically, is the question: ‘what is light?’ The question is important for two reasons. First, it makes us immediately suspect that its answer is different for us today than it was fifteen hundred to two thousand years ago, which is the floruit of early Christian thinkers. Second, it helps us understand that until we have a better grasp of how early Christian thinkers conceptualized physical light, the full meaning of their theological light language will remain sealed to us, regardless of its literal or metaphorical use. Curiously, it is this question that has been omitted in the previous discussion. It is this question that is the subject matter of this book. Due to its novel research question, this book adopts a novel method. As a working hypothesis, it distinguishes at the outset between two different senses of the term ‘light’ in the locution ‘metaphysics of light’. In its traditional and extended sense, ‘light’ denotes ‘being qua being’, ‘pure being’, ‘being as such’, and the like, i.e. ‘being’ as the subject matter of traditional metaphysics in all its abstractness and generality. This is the sense used by Baeumker and Beierwaltes, which I will from now on refer to as the ‘metaphysics of light’ lato sensu. This is a stretched sense of ‘light’ because no matter how we unpack its meaning (literally or metaphorically), the term denotes something different than the common and familiar sense of theagentor stateofphysicalillumination. By contrast, it is in the latter sense that I will from now on employ the term ‘light’ in this book. This is a narrow sense, since ‘light’ retains its known and commonly available usage in ordinary language, as when we speak of ‘the light of the sun’ or ‘the light that illuminates a dark room’. This ordinary meaning of ‘light’ is different from its extended meaning. It no longer refers to the whole of reality but only to a part of it, namely the natural process, condition, or event that we phenomenologically attest as making things visible. If we now ask what this process, condition, or event is, we open up two different but interrelated fields of enquiry, depending on what we mean by the question. If we mean howlight manifests in the visible world, we
