In the early 1980s a remarkable piece of evidence was uncovered about the importance of the brain in our everyday conscious life, but it has not been widely discussed since. At that time a young man was given one of the earliest brain scans. He had hydrocephalus, commonly known as "water on the brain", which is a rare medical condition in which the fluid filled ventricles of the brain are excessively enlarged. In severe cases this can dramatically inhibit the development of brain tissue, and in the case of this man resulted in him having only a small fraction of the normal amount of cortex. The doctor who studied him described him as having "virtually no brain".¹ Yet despite this he had led a full life, having obtained a first class degree in mathematics. Many other similar cases are documented in the medical literature (Berker et al. 1992).