Because Christianity is founded upon a written revelation, the danger has always been that the power of the word will be exaggerated. So, despite the continuing protests of mystics over the ages about the limitations of language, precisely the same kinds of test for doctrinal orthodoxy or linguistic propriety have come to be applied in areas where they are either less suitable or indeed quite inappropriate. This is in my view one of the major stumbling-blocks which has plagued the Christian appropriation of art. A verbal checklist is applied, rather than care being taken to ascertain what it is that the artist is trying to achieve. The element of imaginative engagement is thus missed, as too is the fact that, because artists have not the same freedom to qualify as have writers, their metaphors have to be at once more forceful as well as—inevitably—more easily subject to misinterpretation. Such contrasts, though, far from being a weakness, can have much to teach us about the explication of doctrine. The extent to which different sorts of issue are raised by the visual as distinct from the verbal is well indicated, I believe, by the various types of presentation to which artists have resorted in developing imagery to highlight the significance and relevance of the doctrine of the Trinity.
Over the course of the centuries, quite a number of different forms of allusion have been attempted. At the risk of oversimplifying, I propose in what follows to identify three main types of approach. Inevitably, to some degree any type of classification prejudges issues, detecting common lines where others may prefer to see none, but whatever faults the method may have, it at least enables us to avoid a purely chronological investigation. So I propose we look at artistic representations under three heads, what I shall call triadic, incarnational and societal images. Very