 This section would be incomplete without at least mentioning Tillich’s “ground of being theology” in closing (model 23). His view is not filed into the range of God-world relations above because it is famously difficult to categorize: Christopher Demuth Rodkey (2013) says Tillich has been read variously as a panentheist, deist (i.e., dualist), and pantheist, and that it is in fact best to characterize him as none of the above but rather as an “ecstatic naturalist”, where the Power of Being delivers the naturalism (since this Power is “the power in every thing that has power”) and the Depth of Being delivers the ecstasy (persons experience this Power of Being ecstatically, as holy). This interpretation tracks Tillich’s method of correlative theology in Systematic Theology I and II: ecstasy is a “state of mind” which is “an exact correlate” to the “state of reality” of the power of being which animates and transcends the finite world (see, e.g., Tillich 1957b: 13). So for Tillich, God is the power or energy that animates the world which, when truly encountered, provokes ecstatic response. This view is spare enough that it is not obvious how someone might work up an “ultimate concern” about God, another of Tillich’s central ideas mentioned at the start of this entry (1957a, e.g., 10–11). Tillich will have to hypothesize that the ecstasy provoked is, for believers, strong enough to rouse such a concern.