Synesthesia

What is the colour of five? What does blue taste like? Believe it or not, some people can answer these questions. These people have an rare variety of perception called synesthesia. Synesthesia literally means joined sensations, a condition that causes certain sensations to "leak" into one another. Its much deeper than a simple association or metaphor; synesthetes don't think about a sound when they see a colour, they actually hear the sound! This raises all sorts of questions regarding our view of the world and reality. Do we all have an innate form of synesthesia, possibly repressed? Who knows, but the more I think about this condition the less I'm suprised (and the more I realize how little we know about ourselves). Yet another bizarre scientific discovery...