KNOWLEDGE Hence, the unique, eternal, unchanging Ideas have their existence in the unique, eternal, unchanging Mind of God ‘Ideas are archetypal forms, stable and immutable essences of things, not created but eternally and unchangeably existent within the divine intellect’ (83Q 46 2) Augustine on Divine Illumination Human beings acquire their own ideas not by recollection (as Plato thought) nor by abstraction (as Aristotle thought) but by divine illumination ‘Illuminated by God with intelligible light, the soul sees, by means not of bodily eyes but of the intellect which is its crowning excellence, the reasons whose vision constitutes its ultimate bliss’ (83Q 46, end) Much has been written about Augustine’s theory of illumination Is illumination necessary for all knowledge, or only for the a priori knowledge of logic and mathematics? If Ideas are the contents of the divine mind, how can a Wnite mind come in contact with them without seeing God himself? How is the vision of God which on this account is necessary for the basic understanding of geometry to be distinguished from the vision of God which is the Wnal and exclusive prerogative of the blessed in heaven? In my view, such discussions are unrewarding Augustine does not have a thought-out theory of illumination, such as some of his medieval followers later developed He is simply using a metaphor, which even as a metaphor is never worked out in a coherent and systematic manner Representing intellectual operation in terms of bodily operations is a natural and universal feature of human languages In English we speak of grasping a concept, or of a proposition as ringing true or smelling Wshy; but of all our bodily senses it is vision with which the action of the intellect is most often compared When we assent to a proposition without being led to it by argument or persuasion, we may say that we simply see it to be true: using the same metaphor, we speak of intuitive knowledge Augustine can speak quite naturally in this way of intellectual vision or of the eye of reason Talk of illumination, however, adds an extra feature to this natural metaphor It implies that when we understand, there is some medium through which we understand, just as light is the medium of our vision when we see colours It implies that there is a source from which this medium originates, in the way that the sun and lesser luminaries are the 159