All Christology begins "from below." Rahner's distinction, "from below/from above," describes the plots of the Christological stories we tell, but not the genesis or sources of those stories. Too often we fail to make that distinction.
Christology begins in disciples' imaginative responses to the "Caesarea Philippi" question. That's what Mark portrays the disciples and Peter doing. They answer Jesus imaginatively with code words ("Elijah," "John the Baptist," "Messiah") that are ...