The proverb ‘seeing is believing’ has the power of truism in the tyrannical world of Western common sense. The visual arts constantly remind us that ‘seeing’ involves perception. Seeing is never unmediated ingestion of ‘objective’ reality. There is no simple nor automatic relationship between ‘what you see’ and ‘what you get’. What one sees is always mediated by how one thinks. Interpretation of what one sees depends on a wide range of environmental, individual and social factors. Visualisation is always contextual. In Fred Williams’ etchings of Australian trees, for example (Figure 2.1), one faces a genuine difficulty in separating the forest and the trees. This ambiguity is neither mere illusion nor artistic manipulation of perspective to draw us to new insights. Rather it is a window on the co-existence of simultaneous realities – simultaneous meanings and competing perceptions. The alternative visions co-exist. In one well-known illustration (Figure 2.2), most observers are initially confronted by either the old hag or the young woman in a hat. Most people can visualise the alternate image when it is pointed out to them; but which one is the ‘correct’ image? If ‘seeing is believing’, which image is the ‘right’ one; which reality are we to believe in? In these illustrations, the images are mutually constitutive. One does not exist without the other. They cannot be disentwined. As Escher’s ‘Day and night’ images (Figure 2.3) demonstrate so clearly, this is not just a matter of illustration, but bears some relationship to material realities. Many aspects of material reality interpenetrate and mutually constitute each other in a similar fashion, with the one being inseparable from the others.