This can be seen in Jenson's theology as well. When he asks who God is, there is no metaphysical response. He claims that for a Christian, God is he who raised Jesus Christ from the dead. God is revealed in history and revelation, not in metaphysical reasoning. We discussed something similar a while back, this is similar to the more accurate translation of the divine name in Exodus, "I will be who I will be". For the Jews, God is he who freed the Jews from Egypt, he is only defined by his actions. This tradition culimanted in Barth who basically claimed that all knowledge about God comes straight from above (senkrechts von oben), all reasoning from below is just religion in the derogatory sense of the word. Personally I think this approach is way too one sided, and prefera theology where "from below" and "from above" must meet somehow.