ABSTRACT
This chapter argues that the Trinitarian theology of the Cassiciacum dialogues is fundamentally pro-Nicene in shape, though also influenced both directly and indirectly by Neoplatonic philosophy, especially in Augustine's presentations of the so-called first and second hypostases. It examines Plotinus' depiction of the third or lowest of these subsistent realities in consideration of the thesis that Augustine attempted to assimilate this depiction with the Christian doctrine of the Holy Spirit. Augustine clearly conceives of the Father, the Son, and the Spirit as distinct and irreducible and yet as one God, one substance, and co-eternal. Augustine has more to learn about Neoplatonism and pro-Nicene theology. The catechumen who had recently been led to a Nicene perspective of God through the assistance of Neoplatonic philosophy could continue to invoke the assistance of this philosophy on his own and in his own ways.
