Theology begins with an unwillingness to believe that the reality of human beings and human society can be fully explained solely in material terms. Its agenda and subject matter is the exploration of how an openness to a different or fuller explanation of those realities is best articulated and an exploration of how the consequences of such openness bear upon individuals and society, their beliefs, the axioms and principles of social conduct and responsibility. Theology in the specific sense of God-talk is a particular subset of that exploration — the theistic premise regarded as the most appropriate starting point to construct a positive alternative to the purely materialistic explanation of what is — though the openness in many cases will include an openness to the possibility that the theistic premise is itself wrong or misleading’. (Jimmy Dunn)
I pulled this quote from Jason's blog again. He cut this from an interview with Dunn. For links to other great figures in theology check out the full post.