Divided Brain

I have just read The Master and his Emissary: The Divided Brain and the Making of the Western World by Iain McGilchrist - a brilliant book but (I was going to write 'not for the faint-hearted', but when did anybody ever say a book was for the faint-hearted?!) but demanding. It romps through some neurology, draws out the implications, then reviews major episodes in Western history from Homer to the present day. The title is taken from a fable in which a wise spiritual master ruled a small but prosperous domain. As its boundaries spread he was obliged to use trusted emissaries to rule its outer reaches, but the most trusted emissary decided he should be the master, and so he usurped power and used it to enrich himself. The Master stands for the right hemisphere of the brain, larger and better connected than the left, vigilant over all that happens in the body and around it, quiet but emotionally responsive and musically sensitive, the seat of face recognition. The Emissary stands for the left hemisphere, with the power of speech and precise calculation but limited emotional sensitivity, manipulative in the execution of particular tasks but neglectful of the wider context. McGilchrist's thesis is that in Western culture the right hemisphere has been allowed to lead at times but that overall the left hemisphere has become increasingly dominant. He is careful to insist that both hemispheres are involved in normal behaviour; most of what we know about their differences comes from people with extensive brain damage or surgically separated hemispheres.