Basil of Caesarea, Inseparable Operations, and the Divinity of the Holy Spirit

Basil of Caesarea is one of the most prominent pro-Nicene theologians and defenders of the Holy Spirit. One of the common features of pro-Nicene theology is the doctrine of inseparable operations—that all acts of the triune God in creation are undivided. But what role did the inseparability principle play in Basil’s trinitarian theology, especially regarding the Holy Spirit? Examining Basil’s historical context and his major works Against Eunomius and On the Holy Spirit, this article argues that the doctrine of inseparable operations is a critical and proper element in the bishop’s trinitarian theology and, therefore, is vital to his defending the Holy Spirit’s co-divinity alongside the Father and the Son. Basil’s coherence of the inseparability axiom with the other elements of pro-Nicene theology thus serves as a fitting case study of classical trinitarianism. His legacy has become our inheritance.