Trinity and Divine Attributes in Christian Polemic

Sidney Griffith’s chapter on the genre and content of Christian theology in Arabic, particularly apologetic literature, raises interesting questions for Trinitarian theology.  In light of the preference in Christian-Muslim polemics for arguments from reason, Christian articulations of the Trinity situated the doctrine in the context of Islamic discussions of “the ontological status of the divine attributes” (Griffith 95).  This claim effectively reduced the the typical attributes describing God’s “essence and action” to three “substantial” attributes, namely existing, living, and speaking (95). These attributes, in Griffith’s phrase, “indicate the three persons or hypostases of the One God” (95).  

I would like to see this argument fleshed out more extensively, particularly in regard to its continuity with and fidelity to the Nicene-Constantinopolitan understanding of the Trinity.  What is a “substantial attribute” as distinct from any one of the others? Are existing, living, and speaking to be identified with the particular persons of the Trinity? If so, how could “living” and “speaking” fail to be attributed principally to Christ, the Word who declares ,”I am the Life”?  Again, if a “substantial” attribute is to be identified with a particular person of the Trinity, how is the relationship of the Triune persons reflected in the relationship of the three substantial attributes? Alternately, if a “substantial attribute” is not to be identified with a particular person/hypostasis, what does it mean to say that these three attributes “indicate” the three persons of the Trinity?  These specific questions drive towards a more general concern, that of how the doctrine of “substantial attributes” can remain faithful to the scriptural foundations of Trinitarian doctrine. What was the influence of this approach to Trinitarian theology in the wider Christian world?