The Best Book I Ever Read: The Master and His Emissary

A Book Review of The Divided Brain and the Making of the Western World By Iain McGilchrist

This book is brilliant. On the one hand, I feel bad for delaying reading it. But on the other hand, the wait allowed me to get into other topics, which made me get a lot more out of McGilchrist’s work.

The book starts by clarifying some myths about the brain hemispheres, mostly coming from pop-psychology books, especially old ones. For example that the left hemisphere uses logic, words, and language, while the right hemisphere uses feelings and symbols. Some even reduce the whole hemisphere to binary functions, such as rationality vs intuitive, system I vs system II, or male brain vs female brain. This is all false.

However, there is another common conception in pop psychology. Not about myths regarding hemisphere differences, but that hemispheric differences themselves are a myth. This, again, is incorrect. There are most definitely differences across the two brain hemispheres; they just aren’t as simplistic as the examples first mentioned. Generally speaking, the difference isn’t on “what” is done, but “how” is done. The left hemisphere deals with units, the right with aggregates. The left hemisphere is focused, and engaged with a goal in mind. The right does not have a “purpose”. The left hemisphere deals more with abstractions. Things that are clear, fixed, and explicit. On the other hand, the right hemisphere deals with the concrete, the individual, the evolved, interconnected, and implicit. They are two different takes on reality that work together to make a coherent understanding.

Most importantly, while the left hemisphere has traditionally been considered the main hemisphere (mostly because it’s associated with language), he argues that the right hemisphere is in the fact the most important. And almost all cognition involves starting at the right hemisphere, then going to the left, and back to the right. What the title is alluding to is that the right hemisphere is the master, while the left hemisphere is his emissary. And when the emissary overestimates his role and tries to overtake the master, things don’t go well. And the left hemisphere always has this tendency. It can’t break out of his own narrow perspective and consumes everything under its categories and conceptualizations.

The first part of the book deals with all the psychological and neuro-imaging evidence for these claims. Evolutionary analysis, split-brain experiments, brain damage, and more. However, surprisingly, I don’t consider this a psychology book. Rather, this is all the groundwork for the second part of the book, which is heavily philosophical. The beginning is more or less to convince you that there is such a thing as hemispheric differences and explain what these are.

While this is important, I feel this was overly done. It was a bit repetitive and somewhat tedious to read at times. If you’re mostly concerned with the philosophical element, you could honestly most of the first part entirely and still get the main benefit of the book. Just read the first couple of chapters and move to Part 2. This will save you about 100 pages and make the book more enjoyable, in my opinion. If you’re curious about all the specifics of hemispheric differences and you like neuropsychology, then feel free to read the whole thing as intended.

The second part of the book is the true gold of this book. He argues that not only do we have two different modes of interpreting the world, but that these modes can be emphasized, and they can be influenced and influence culture itself, which produces massive cultural shifts in human societies. He begins with Greece in the 6th century BC Athens, the Renaissance, the Reformation, the Enlightenment, Romanticism, modernism, and post-modernism. He explains how each period can be seen in the light of hemispheric differences. I was quite sceptical at first, but he argues it well.

The biggest thing I got out of the book was how there is much more to reality than what we can rationally apprehend and how our view of the world is filtered and pre-interpreted without us even knowing it. This is something I’ve long thought about it, but he articulates these problems very well, and linking it to neuroanatomic makes the case a lot stronger. It’s also mindblowing how knowledgeable the author is and how wide his scope is when presenting his case, using philosophy, literature, painting, sculpting, poetry, and music. It’s really hard to try to justify how these could have possibly been influenced by something like hemisphere differences, but after reading the book the link is really hard to ignore.

Honestly, I think for a lot of people, this would change how you think about the world, especially if you’re more oriented toward rationality, language, and science. While I was already familiar with many of the philosophical ideas he was trying to present, he linked them with things I never knew or never thought about and made them a lot more explicit. Especially regarding the Reformation and Enlightenment, it really added an incredible amount of in-depth to my understanding of such periods, their evolution, and their broader context in the Western world. His exploration of metaphor and poetry was also brilliant.

Even if the case for brain hemispheric difference is massively overstated, his thesis would still be incredibly insightful. There are most definitely two “realities” to our experience. They seem to be influenced by hemispheric differentiation, but if they are not, their ontological status is impossible to ignore nevertheless, regardless of its neuroanatomic origin. It’s not an easy book, honestly. At times it is very dense, but it pays off. The shift in perspective is incredible, and for anyone that is truly interested in understanding both how human beings engage in sense-making and also the history of ideas in the Western world, you can’t afford to skip this masterpiece.

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I also have a philosophy podcast. If you want to check it out look for Anagoge Podcast.

Tiago V.F.