 Brain bisection cases first. On the standard way of conceptualizing these cases, the key evidence for a duality of some kind is that there appear to be situations in which whatever is conscious of some items being experienced in the body in question is not conscious of other items being experienced in that same body at the same time. We looked at two examples of the phenomenon in  Section 4.1,  the word TAXABLE and the doing of arithmetic. With respect to these experienced items, there is a significant and systematically extendable situation in which to be conscious of some of these items is not to be conscious of others of them in a single unified consciousness where we would expect such consciousness. If so, brain bisection patients fail to meet the conditions for unified consciousness of contents. This seems to be what motivates the judgment that these patients have two centres of consciousness. 