Augustine's philosophy of being, the subject of my lecture, might be approached in two ways. In traditional terms, we might consider the question quid est esse, or alternatively the question quaenam sunt. This latter question is easily explained; it means, roughly speaking, what does the real universe contain or comprise, in a large and general sense. Material objects, of course, we can all accept; but what should be said about minds and spirits and the things with which they are concerned? The other question is more difficult to explain in simple terms. Suppose we translate it ‘What is being?’, we may seem to be asking a question about the word ‘being’; what is the sense which Augustine gives to this word? But in fact we shall discover a whole spectrum of senses. ‘Being’, for Augustine, sometimes appears to express the purely minimal notion of mere existence; but he also uses it as a powerful symbol to formulate his deepest reflections on the spiritual life and the nature of God.