A helpful place to begin in this early discussion by Pannenberg is his comments on “unity.” He writes
Unity is a subject of eternal interest to the philosopher. Unity is the most comprehensive characteristic of being … the quest for the ultimate unity which integrates and thus unifies everything is the question reaching for God … For us, too, the way in which we must test any concept of God is by asking whether it can account for the unity of all reality. If an idea of God fails that test, it does not comprehend the power dominating everything and is, therefore, not a true concept of God. (60)This quote provides an initial touchstone for Pannenberg’s understanding of ontology, noting its fundamental unifying function. In addition to his stress on unity, in this early essay Pannenberg makes clear that his ontology is eschatological, since "this priority of the eschatological future ... demands a reversal also in our ontological conceptions." Here he is following thinkers like Johannes Weiss, who "discovered that ... the Kingdom of God will be established not by men but by God alone." (52, 54). For Pannenberg a key development that follows from this reversal is “the simple observation that God’s being and existence cannot be conceived apart from his rule" (55; this conclusion was also reached in concert with another student and with the examination of other relevant texts). When coupled with “the eschatological understanding of the Kingdom of God” introduced by Weiss, this connection between God’s being and rule entails the judgment that “it is necessary to say that, in a restricted but important sense, God does not yet exist. Since his rule and his being are inseparable, God’s being is still in the process of coming to be" (52, 56).
As noted by Philip Clayton in his preface to Pannenberg's Metaphysics & the Idea of God, this last statement points toward what he calls Pannenberg's "eschatological ontology" (viii). I'm interested to hear from my readers to what extent they believe that Clayton's description of this ontology as "controversial" back in 1990 remains true today, if at all (ibid). Regardless, I'm glad that Clayton pointed me toward this concept and text, as I find them fascinating and potentially loaded with implications for a missional portrait of God, as I hope to research and develop throughout this semester. For now however, lets further investigate Pannenberg’s belief that when considering God and God’s Kingdom “futurity is fundamental.” As he writes “to put it in the language of the philosophy of religion, the being of the gods is their power.” Thus, “the God of the coming rule is related to all that is finite and is the power determining the future of all that is present.” Believing that this conviction is grounded in “the message of his imminent Kingdom,” Pannenberg argues for the description “God as the power of the future" (53, 55-6).
Pannenberg summarizes the implications of this eschatological and unitive ontology and its relationship to God; “If the Kingdom of God and the mode of his existence (power and being) belong together, then the message of the coming Kingdom of God implies that God in his very being is the future of the world. All experience of the future is, at least indirectly, related to God himself" (61). When taken with the rest of his summary one can begin to discern how Pannenberg’s ontology and doctrine of God imply panentheism.
However, for now we must stop with this quick outline of these two features of his ontology, its unitive and eschatological nature, and its connection to his doctrine of God. While viewing these two components alone as comprising his ontology is almost certainly presenting only a partial picture, and the possibility for misunderstanding lurks given the brevity of the post and the use of a single source, nonetheless from my initial forays into Pannenberg and his interpreters I feel confident that these are dominant elements in his thinking, and deserve careful consideration.