Split Brain: The human brain is split into two cortical hemispheres. These hemispheres are joined together by the corpus callosum, a group nerve fibres that allows the two hemispheres to communicate and coordinate with one another. The common assumption is that the corpus callosum unites the two hemispheres into a single conscious being, i.e. you. But there is some evidence to suggest that this might not be the case. In split brain patients (i.e. patients whose corpus callosum has been severed) it is possible to perform experiments that result in the two halves of the body doing radically different things. In these experiments it is found that the left side of brain weaves a narrative that explains away the discrepancies in behaviour between the two sides of the body. Some people interpret this as evidence that the left half of the cortex is primarily responsible for shaping our conscious identity. But what if that is not what is going on? What if there are, in fact, two distinct conscious identities trapped inside most ‘normal’ brains but the left-side consciousness is the dominant one and it shuts down or prevents the right side from expressing itself? It’s only in rare patients and constrained experimental contexts that the right side gets to express itself. Suppose in the future that a ground-breaking series of experiments convincingly proves that this is indeed the case. Should we do something to liberate the right-side consciousness?

Read more about it in "Are we in the midst of a moral catastrophe?"