The presence of consciousness in the right hemisphere is especially difficult to deny when the subject possesses linguistic abilities on both sides of the brain, because in this case the divided hemispheres often express different intentions. In a famous example, a young patient was asked what he wanted to be when he grew up: his left brain answered, "a draftsman," while his right used letters on cards to spell out the word "racing driver." Sometimes the divided hemispheres even address each other directly, in the form of a verbalized interhemispheric argument.
In this case, each hemisphere may have beliefs of its own. Consider what this says about the view, widespread in Christianity and Islam, that a person's salvation depends on having the correct faith in the correct god. If the left hemisphere of a split-brain patient accepts the divinity of Jesus while the right does not, should we assume that he now has two immortal souls, one destined for the company of angels and the other for eternity in hell?
Sam Harris, from the book "Waking Up," on patients whose brain hemispheres were surgically separated for medical reasons.
https://web.archive.org/web/20150905231146/https://www.samharris.org/waking-up