Abstract
On the basis of Chapter 15 of Anselm's Proslogion, I develop an argument that confronts theology with a trilemma: atheism, utter mysticism, or radical anti‐Anselmianism. The argument establishes a disjunction of claims that Anselmians in particular, but not only they, will find disturbing: (a) God does not exist, (b) no human being can have even the slightest conception of God, or (c) the Anselmian requirement of maximal greatness in God is wrong. My own view, for which I argue briefly, is that (b) is false on any correct reading of what conceiving of requires and that (c) is false on any correct reading of the concept of God. Thus, my own view is that the argument establishes atheism. In any case, one consequence of the argument is that Anselmian theology is possible for human beings only if it lacks a genuine object of study.