“The mind is an incredibly complex machine, Stuart. Nobody fully understands the workings of it. Everyone has their own perception of the lives they lead and the environment in which they live them. For most of us, the perceptions are complimentary, so we accept reality as a collective experience. For instance, who is to say you see the colour of this t-shirt in the same way I do. We both perceive it as green, but whether or not we see the same colour, we can’t say. It doesn’t matter though as long as we all agree. Nevertheless, if a person comes in and says my t-shirt is red and everyone else says it is green then we have to question his or her perception of my t-shirt. There has to be a reason why their perception is different to ours. Of course, in that case, we would suspect colour blindness, a condition in which the receptors in the eye send erroneous signals to the brain. For whatever reason, Stuart, we are all seeing green, but you see red. We need to find out what is causing your brain to do that.”