Contemporary theological discourse often narrowly frames aseity as God’s self-sufficiency or independence from creation. However, this construal risks divorcing aseity from the dynamic life of the Trinity. While respected thinkers like J.P. Moreland and William Lane Craig define aseity as “God’s self-existence or independence,” John Webster contends that such a limited definition fails to capture aseity’s full essence. Webster defined aseity as “the glory and plenitude of the life of the Holy Trinity in its self-existent and self-moving originality, its underived fullness” (God Without Measure, 13). Rejecting a static notion of mere self-sufficiency, Webster aligns with the historical practice of relating God’s aseity with his eternal blessedness and a foundation for Trinitarian theology. For Webster, “God’s life a se includes the Son’s relation to the Father as the one whom the Father begets (passive generation), and the relation of the Spirit to the Father and the Son (passive spiration)” (God Without Measure, 20).
This rich understanding of aseity as the plenitude of divine life is crucially important for evangelicals, as the doctrine is fundamental to rightly comprehending God’s nature and Trinitarian theology. Webster’s perspective on aseity as eternal blessedness should profoundly shape discussions between theistic personalists, who emphasize God’s relation to creation, and classical theists, who stress his metaphysical perfections. This paper will examine the exegetical foundations and historical theological formulations underpinning Webster’s view. It will examine how Webster’s framing of aseity enriches Trinitarian theology for contemporary evangelicalism.