 Dulles’s models are theoretical constructions or “ideal-types”, and elements from different models can be combined. For example, theologians like Paul Tillich and Karl Rahner combine the “new awareness” model with experiential and historical elements (Tillich 1951: 111–118, 120–122; Rahner 1966). It has been argued, however, that none of the manifestational models presented above can provide—either separately or in combination—a reasonable account of how knowledge of God’s “theistic properties” (omnipotence, omniscience and infinite goodness) comes about. Such an account requires appeal to propositional revelation at some point, or at least to traditional natural theology (Wahlberg 2014: Ch. 3).