The Metaphysics of Light in the Hexaemeral Literature: From Philo of Alexandria to Gregory of Nyssa by Isidoros C. Katsos (review)

Reviewed by: The Metaphysics of Light in the Hexaemeral Literature: From Philo of Alexandria to Gregory of Nyssa by Isidoros C. Katsos Alexander H. Pierce Isidoros C. Katsos The Metaphysics of Light in the Hexaemeral Literature: From Philo of Alexandria to Gregory of Nyssa Oxford: Oxford University Press, 2023 Pp. viii + 248. 90. 00. There has long been sustained interest in the study of ancient thought regarding the relationship between light and vision, not to mention the significance of light imagery used more generally across ancient texts. Isidoros Katsos examines the formative Jewish-Christian metaphysics of light as a contemplative exercise within the hexaemeral tradition instantiated in the writings of Philo, Origen of Alexandria, Basil of Caesarea, and Gregory of Nyssa. Katsos frames his study as a major intervention within a field of literature that has failed to grasp what light was understood to be in itself. The project of this book is to work towards a broader, more ordered metaphysics of light by first taking a major step back to understand the physics of light. The book begins with an introduction, then proceeds in three chapters, followed by a substantial set of "conclusions" and three considerable appendices. In Chapter One, Katsos attributes to previous scholarship an elision of the difference between reflection on light and sight, the perceived and perception itself. The difficulty, as Katsos sees it, includes a lack of research regarding the ancient physics of light from what he calls a "luminocentric" perspective, and the scholarly denial that there was any ancient consideration of physical light per se. But ancient Christians recognized that there was more to light than its being seen by our eyes (the prevailing "oculocentric" viewpoint) ; it has a nature and structure of its own. Katsos contends that there was an ancient physics of light and that it was furthered in early Christian hexaemeral literature as a crucial part of the scriptural witness. The hexaemeral physics of light was intended to lead readers of the creation account in Genesis from the sensible to the intelligible world. Chapter Two addresses a twofold difficulty of Katsos's proposed innovation, namely, the need to exhibit the possibility of an ancient physics of light and to demonstrate its value. Katsos identifies the logos as the bridge between scripture End Page 297 and natural philosophy, building a case for how early Christians saw in the creation narrative of Genesis not only a physics of light but also a more general account of physics. The physicality of light was definitive, Katsos argues, for Origen's influential interpretation, which attested to the import of hexaemeral physics, the phenomenal purview of God's creative work. Gregory of Nyssa's work aids Katsos in asserting the importance of light being understood as the natural capacity of fire, where fire is the luminous substance and light its illuminating power. This alignment supported the Christian defense of the creation narrative against its philosophical detractors, for it suggests agreement between Greek thought and the text of scripture concerning the identity of light and fire. This connection clarified for Gregory that Gen 1. 3 speaks of the creation of light with fire. Katsos suggests that Gregory captures the preceding tradition by asserting a physicalist interpretation of the creation account in which the sensible world is the object of God's creative activity. Chapter 3 considers what it means to speak of light in relation to fire. Katsos attempts to "reconstruct" a systematic theory of hexaemeral light by means of the hexaemeral homilies of Basil and apology of Gregory. He argues that their physicalist reading of the creation account directs the reader to contemplate both scripture and nature such that physics gives way to metaphysics. In the case of light, there is a progression from substance (fire) to emission (radiant light) and transmission in space (ambient light). While light is nothing but luminous fire particles in space, it has primary, secondary, and epiphenomenal effects. This logic supports Katsos's claim that luminocentrism more capably accounts for light's causal priority in relation to sight than does oculocentrism. Katsos contextualizes this Cappadocian synthesis by suggesting that the logos of physical light in Gen 1. 3 is our first opportunity. . .