The image of the cave described by Plato in Book VII of the Republic is the most frequently quoted emblematic example of the belief in the illusory nature of what sight transmits to the mind. ‘We must compare the world of the senses with the view of those who live in a prison’, says Socrates, referring to the cave in which there are men in chains who can see nothing but a wall onto which are projected shadows of objects lit by a fire behind them, and who, ignorant of the objects themselves, are inclined to give more credit to the shadows than the objects, as long as they are not free and able to rise in their souls from the visible to the intelligible world.

The whole history of human thought could be rewritten in terms of the confrontation between the eye and the mind. The immediate power, poignant charm, evocative force of the messages sent from one to the other have encouraged a bewitching abandon, internal illuminations, but also moments of deliberate blindness and destructive furies. Starting from periods of vague iconophilia, a large number of societies have moved to periods of obsessive iconoclasm in public forms of representation. From sublime experiences of divine mystical visions to the most degenerate forms of violence and pornography, it is the visual image, perceptible or mental, that imposes itself.