“Truly Repay the Debt”: Aetius and Eunomius of Cyzicus

Andrew Radde‐Gallwitz

in Basil of Caesarea, Gregory of Nyssa, and the Transformation of Divine Simplicity

Published in print October 2009 | ISBN: 9780199574117
Published online January 2010 | e-ISBN: 9780191722110 | DOI:

Series: Oxford Early Christian Studies

“Truly Repay the Debt”: Aetius and Eunomius of Cyzicus

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Chapter 4 examines the teaching on divine simplicity of Aetius and his disciple Eunomius of Cyzicus, the principal opponent of Basil and Gregory of Nyssa. An initial section looks at Aetius' claim that ingeneracy is God's essential attribute. It critically examines Raoul Mortley's thesis that Aetius is dependent on the fourth‐century Neoplatonist Dexippus. The bulk of the chapter focuses on Eunomius, arguing that his account of simplicity is based upon his epistemology, which is driven by the desire to ‘repay the debt’ humans owe to God of describing God exactly as God is. For Eunomius to know truly is to know what something is, that is, to know its essence‐a theory labelled the ‘priority of definition’. For Eunomius, divine simplicity implies that ingeneracy, if truly said of God, is neither a product of mere human conceptualization, nor a merely negative title, nor a ‘part’ of God. Rather it names the essence of God. According to Eunomius, simplicity also implies the ‘synonymy principle’: all titles used for God are semantically equivalent with ‘ingenerate’.

Keywords: Aetius; Raoul Mortley; Eunomius of Cyzicus; ingeneracy; identity thesis; conceptualization; divine simplicity; essence; priority of definition; synonymy principle

Chapter.  9902 words. 

Subjects: Early Christianity ; Christian Theology

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