This book is an essay in the philosophical history of some theological metaphors. The metaphors – of ‘interiority’, of ‘ascent’, of ‘light and darkness’ and of ‘oneness with God’ – appear to have occupied a central role in the description of the Christian ways of spirituality for as long as Christians have attempted to give one. And they still do. There are many other metaphors – in particular, there are many metaphors of Christian love – whose role is equally crucial, but I have chosen to study the particular metaphors I have mentioned, and not others, for a number of reasons, among which the following are perhaps the most important.

First, because the metaphors of inwardness, ascent and light–darkness form a closely related cluster; secondly, because taken together they have an impact on the description of the Christian way of life which is distinctively ‘negative’ or ‘apophatic’, for which reason I have called them ‘metaphors of negativity’; thirdly, because they are metaphors characteristic of a Neoplatonic style of Christian theology, so that the study of them opens up lines of enquiry into an important aspect of the influence of Neoplatonism on Christian spirituality; fourthly, because they are metaphors which retain a currency still, and so it seemed that the study of them could also shed some light on what they do for us, by way of an account of the traditions from which we inherited them; and finally, this last reason seemed important to me because I suspected when I embarked on this study that the purposes which these metaphors serve for Christians today are very different from the purposes which they served within the ancient and mediaeval traditions of Christianity in the West, and that therefore it might be useful to know what those differences are.