Oliver Sacks explains the different but equal hemispheres of the brain.
Question: How are left and right brains different?
Oliver Sacks: Hemisphere differences are very striking, not only in human beings but many primates and other animals. And its doubleness is partly built into the vertebrate frame so that we have two kidneys and limbs on each sides. We’re symmetrical in most ways.
But the two halves of the brain, although normally they always worked together, they do seem rather different in character and function. And that’s very much as if the dominant hemisphere, which is usually the left hemisphere of the brain, is concerned especially with logical thought and analysis, and sometimes relatively routine, intellectual routines of one sort and another. And the right half of the brain much more to do with emotion, with novelty, with intuition and, to some extent, with identity.
And one can’t really say that one half is more important than the other because they have to come together completely.