Chapter 1: Kant
Part 1 begins with whether there is a question, i.e., whether we can discourse about God. Several modern theologians assert we cannot speak intelligibly about God, since Kant has shown us he belongs to the noumenal world (the world “as it is,” versus the phenomenal world, the world “as it appears”). Those things in the noumenal world we cannot speak or predicate about, which would then include God. However, this point is usually an assertion, not an argument, and they have not read Kant well. One cannot predicate of God, which means one cannot attribute to God the concept “being such that our concepts don’t apply to it,” and hence the claim seems initially self-refuting. But we should examine further Kant’s metaphysics and its two different interpretations.
Kant often does predicate of or refer to God. It does not seem that Kant believed we could not refer to God then. But his metaphysics has been interpreted this way. Kant is known for saying things like “it follows that the employment of the categories can never extend further than to the objects of experience.”
But are the noumena and phenomena two different worlds or one? This would make a difference regarding our predication of God. In the one-world interpretation, the Dinge (“things”) are all that exist, so any problems of predication would apply equally to all objects. Hence no special objection to predication of God occurs in this case. On the two-world picture, there is a moderate sub-picture, in which our concepts apply to noumena but we cannot have knowledge of them, hence we can predicate of God. On the radical sub-picture, the Dinge may not be predicated about or known, and they depend on our transcendental ego(s) for their existence due to a causal relation. On this picture, we could not predicate of God.
But the entire picture is self-referentially incoherent. If the noumena cannot be known or predicated of, then Kant cannot apply such concepts to them as “atemporal,” “aspacial,” and “causally connected to transcendental egos.” Besides this, the antinomies that undergird the idea of transcendental idealism are unsuccessful. Thus, Kant is no source for theologians who wish to argue we cannot predicate of or refer to God.