The Master and His Emissary by Iain McGilchrist: Overview

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What’s the truth about the difference between the right brain and the left brain? Is one dominant over the other? Is one more important than the other?

In The Master and His Emissary, Iain McGilchrist argues that pop psychology has given us a wrong—and dangerous—impression of the brain’s hemispheres. He contends that the right hemisphere is more important—and that our failure to recognize this threatens to rob our lives of meaning and happiness.

Continue reading for an overview of this contrarian book.

Overview of The Master and His Emissary by Iain McGilchrist

In his 2009 book, The Master and His Emissary, Iain McGilchrist cites an array of scientific evidence intended to dispel the myth that the right hemisphere is “minor.” According to this myth, the right hemisphere only grounds supposedly gratuitous functions like artistic ability, imagination, and sentiment, while the left hemisphere grounds vital functions like reason, linguistic understanding, and arithmetic. For this reason, pop culture often calls those inclined toward artistic pursuits “right-brained,” while calling those inclined towards analytical pursuits “left-brained.” 

Against this misconception, McGilchrist contends that the right hemisphere is actually dominant over the left hemisphere, as shown by its role in our capacity for attention, value judgments, and comprehending meaning. Further, he argues that, when a society puts too much emphasis on left-hemisphere functions, the left hemisphere can begin to exert undue influence that depletes our joy and fulfillment. McGilchrist argues that this was the case in historical periods like the Reformation and the Enlightenment and that it’s happening again today. (The book’s title is a metaphor for this undue influence: McGilchrist describes the left hemisphere as a servant looking to usurp its master’s—the right hemisphere’s—proper place.) 

As an Oxford-educated literary scholar and former neuroimaging researcher at Johns Hopkins University Medical School, McGilchrist incorporates fields like art criticism, literature, philosophy—and of course neuroscience—into his wide-reaching argument. Moreover, having authored academic articles across various disciplines in addition to public-facing books like The Master and His Emissary and its follow-up, The Matter With Things, McGilchrist is well poised to present academic research in a manner accessible to the general public.

We’ll first discuss five differences between the hemispheres that McGilchrist says rebut the myth of right hemisphere inferiority. Next, we’ll assess the historical relationships between the hemispheres—first, in eras that exemplified the right hemisphere dominance that McGilchrist endorses, followed by eras in which the left hemisphere became too powerful. To conclude, we’ll examine McGilchrist’s predictions about the nature of a world dominated by the left hemisphere and his reasons for thinking this world would rob us of happiness.

(Shortform note: Reviews of The Master and His Emissary have been mixed. For instance, a reviewer for The Economist argues that McGilchrist is guilty of overgeneralizations when applying his broad thesis about the differences between the two hemispheres to particular historical periods. Others have praised the book’s subtlety along with its thought-provoking nature, noting that such a contrarian work is likely to receive some criticism.)

The Differences Between the Two Hemispheres

To start, we’ll examine five of the hemisphere differences that McGilchrist discusses—differences in understanding meaning, perceiving objects, grasping coherent wholes versus individual parts, processing emotions, and thinking intuitively. While these differences will later illustrate the hemispheres’ historical power struggles, they also illustrate one of McGilchrist’s key claims: The myth of left-hemisphere superiority is misguided, as the right hemisphere is responsible for several of the brain’s most essential functions.

Difference #1: Implicit vs. Explicit Meaning

Despite the popular caricature of the right hemisphere as “silent,” McGilchrist contends that it plays a crucial role in understanding language. By examining the effects of injuries to the right and left hemispheres, he argues that, though the left hemisphere grasps formal linguistic rules, only the right hemisphere grasps the implicit meaning that language conveys.

He notes that, when people suffer from right hemisphere damage (and therefore rely on their left hemisphere), they often speak sentences that are syntactically and grammatically flawless, but nonsensical. In a similar vein, children that suffer right hemisphere injuries struggle to understand entire sentences, even when they know each of the individual words.

McGilchrist concedes that the left hemisphere can understand denotative meaning. For this reason, the left hemisphere has a much larger vocabulary than the right hemisphere. But he reiterates that only the right hemisphere is able to understand the meaning of those terms in context.

Likewise, McGilchrist asserts that only the right hemisphere can grasp metaphors because metaphors don’t depend on the denotative meaning of words, but rather on their connotative meaning.

The upshot, according to McGilchrist, is that the right hemisphere is crucial for understanding the world because we can’t understand the world without metaphors. After all, many aspects of life—such as beauty, love, and pain—can’t be described through denotative language alone. To understand and describe such phenomena, McGilchrist suggests we need to use metaphor.

Difference #2: Abstract vs. Contextual Perception

The right hemisphere’s ability to understand meaning in context hints at another difference between the hemispheres: Only the right hemisphere perceives objects in context. Specifically, McGilchrist argues that the right hemisphere sees objects within broader surroundings, while the left hemisphere sees objects abstracted from those surroundings.

Individual Objects vs. Categorizations

Because the right hemisphere prefers to examine objects in context, while the left hemisphere prefers abstractions of concrete objects, a related difference arises: The right hemisphere thinks in terms of individual objects, while the left hemisphere thinks in terms of broader categories.

Difference #3: Wholes vs. Individual Parts

In addition to perceiving objects in context as opposed to abstracting them, another perceptual difference arises with respect to parts and wholes. According to McGilchrist, because of its preference for abstraction, the left hemisphere breaks objects into their constituent parts while the right hemisphere, with its preference for context, focuses on the whole picture that these parts compose. 

To show as much, McGilchrist cites drawings from patients with hemisphere damage. Those with right hemisphere damage were unable to draw coherent wholes. Those with left hemisphere damage, by contrast, could draw coherent wholes, but with a lack of detail in individual parts. 

Similarly, patients with damage to either hemisphere had differing abilities to recognize parts and wholes.

Global Attention vs. Focused Attention

According to McGilchrist, the reason why the right hemisphere perceives wholes while the left hemisphere perceives parts has to do with hemisphere differences relating to attention. He argues that the right hemisphere is crucial for broader, global attention that grounds the left hemisphere’s narrower, selective attention.

Difference #4: Emotional vs. Dispassionate

Having seen how the brain’s hemispheres differ in their perceptual abilities, we’ll now discuss their differences in expressing and perceiving emotions. According to McGilchrist, the right hemisphere is primarily responsible for processing and expressing emotions.

To illustrate the right hemisphere’s role in processing emotions, McGilchrist examines the brain areas that are activated when we view art. Similarly, McGilchrist points out that feelings of depression and melancholy are associated with excess right hemisphere activation, suggesting the right hemisphere plays a crucial role in processing those emotions.

In addition to processing emotions, McGilchrist claims that the right hemisphere also helps us express emotions. Patients with right hemisphere damage, therefore, lose the ability to convey their emotions through facial expressions.

The Right Hemisphere’s Capacity for Empathy

Because of its superior ability to perceive emotions, McGilchrist asserts that only the right hemisphere has the capacity for empathy. Moreover, McGilchrist points out that patients who suffer from right hemisphere damage often lose the ability to empathize, while those with similar left hemisphere damage retain this ability.

Difference #5: Intuitive vs. Non-Intuitive Thinking

In addition to processing our emotions, McGilchrist suggests that the right hemisphere plays a key role in reasoning—contrary to the stereotype that reasoning belongs to the left hemisphere. In particular, he argues that the right hemisphere specializes in more implicit forms of reasoning, while the left hemisphere specializes in more explicit forms of reasoning. 

To show as much, McGilchrist first examines so-called “aha!” moments, in which we solve some problem while not concentrating on it. These “aha!” moments, he notes, are associated with a sharp uptick in right hemisphere activity, suggesting it helps generate them.

By contrast, McGilchrist asserts that the left hemisphere is better suited for explicit reasoning that involves formal application of logical rules.

The Proper Relationship Between the Two Hemispheres

In light of the differences between the two hemispheres, it’s natural to ask another question: How should the hemispheres work together? That is, what’s the proper relationship between the right and left hemispheres? In this section, we’ll examine McGilchrist’s argument that, contrary to the standard view, the right hemisphere should take primacy over the left because the right hemisphere grounds several of the brain’s most crucial functions.

The Sovereignty of the Right Hemisphere 

McGilchrist notes that, in popular culture, the left hemisphere is associated with more important work, like logical reasoning and problem-solving, leaving the less important right hemisphere subservient to it. But McGilchrist argues that, in an optimally-functioning mind, the right hemisphere is sovereign over the left hemisphere. Although McGilchrist lists a wide array of areas that showcase this right-hemisphere dominance, we’ll focus on three key ones: our value judgments, our capacity for attention, and our ability to grasp meaning. 

Area #1: Value Judgments

According to McGilchrist, the right hemisphere is primarily responsible for our value judgments about the world—what we like, what we dislike, and what we find worthwhile. To show as much, McGilchrist cites studies showing that we form these judgments intuitively, on the basis of our emotions, and only rationalize them after the fact.

As we discussed above, these emotions are processed in the right hemisphere, while the left hemisphere sits on the sidelines. Given the pivotal role these emotions play in our decision-making, it stands to reason that the right hemisphere—which is responsible for emotions and therefore for value judgments—is likewise responsible for our decision-making.

Area #2: Attention

In a similar vein, McGilchrist argues that the right hemisphere’s capacity for global attention takes precedence over the left hemisphere’s capacity for selective attention. After all, we first attend to our surroundings globally, before using that information to focus our attention more narrowly on particular stimuli. McGilchrist suggests that, without the right hemisphere’s ability to attend broadly to our surroundings, the left hemisphere’s ability to selectively attend to specific stimuli would be far less useful.

Area #3: Meaning

Finally, McGilchrist claims that the right hemisphere grounds our comprehension of meaning because the implicit meaning that only it grasps is the foundation of the explicit meaning grasped by the left hemisphere. In other words, McGilchrist suggests that to make something explicit requires some form of implicit understanding: We must comprehend the whole before we analyze and abstract it.

Right Hemisphere Primacy Throughout History

Having discussed the proper relationship between the two hemispheres, in which the left hemisphere is subservient to the right, we’ll now examine three historical eras that, according to McGilchrist, embody the primacy of the right hemisphere: classical antiquity, the Renaissance, and Romanticism.

Yet, before beginning, it’s worth clarifying what McGilchrist means when he says that an era can embody hemispheric dominance (and that this embodiment can change over time from one hemisphere to the other). McGilchrist attributes such embodiment to mimesis, a process by which we empathetically imitate certain ways of thinking present in our surroundings, leading to functional shifts in our brain.

Era #1: The Classical World

The first period that McGilchrist analyzes is the classical period, which lasted from the 8th century B.C. in Greece until the 5th century A.D. in Rome. He argues that most of the classical period demonstrates the proper level of right hemisphere dominance, as shown by classical art, literature, and philosophy. 

First, McGilchrist examines how classical portraits displayed the human face, arguing that their emphasis on individuality is evidence of the right hemisphere’s primacy. He writes that, before antiquity, Egyptian depictions of faces lacked expression and were often abstracted from any individual face—all hallmarks of the left hemisphere. Around the 4th century BC, however, faces grew more emotional and diverse, suggesting an emphasis on the individual that’s strongly associated with the right hemisphere.

Next, McGilchrist discusses the Homeric epics—the Iliad and the Odyssey—and writes that they exemplify the right hemisphere’s capacity for empathy. These epics, he argues, demonstrated a keen insight into the thought processes of their characters, showing a new degree of psychological depth.

Finally, McGilchrist examines early Greek philosophy—especially that of Heraclitus, a Greek philosopher who lived around 500 B.C.—to show that it reflects the right hemisphere’s preference for unity and the implicit. Heraclitus held that the true structure of nature is hidden, and any attempt to explicitly define it using language and logic is bound to fail. He argued that to understand this structure, we must carefully monitor our perceptions, which allows us to see “the unity of opposites” that underlies nature. According to McGilchrist, Heraclitus’s preference for the implicit, for our perceptions, and for unity are all characteristic of the right hemisphere.

Era #2: The Renaissance

Although classical antiquity occurred some two millennia before the Renaissance—the period between about the 14th and 17th century AD in Europe–McGilchrist contends that the Renaissance represented a return to the hemisphere balance of the classical world. He argues that the Renaissance achieved the ideal right hemisphere primacy, as shown by its art and Shakespearean theater.

Regarding Renaissance art, McGilchrist notes that Renaissance artists rekindled perspective in paintings—that is, representing three-dimensional objects to generate the illusion of depth—after it had been absent for over a millennium. He argues that these perspective paintings suggest the ability to see the world in context, as the right hemisphere prefers, rather than the detached view that’s associated with the left hemisphere, as seen in certain medieval religious art that abstracts space and proportion.

With respect to Renaissance theater, McGilchrist argues that the Shakespearean plays that highlighted Renaissance-era drama displayed several strengths of the right hemisphere. And at a broader level, Shakespeare’s tendency to mix different genres shows a similar distaste for the left hemisphere’s categorization.

Era #3: Romanticism

Although the Renaissance represented the optimal balance between the hemispheres, it wasn’t the most recent historical period to favor right-hemisphere tendencies—that achievement belongs to Romanticism, the European intellectual and artistic movement in the early to middle 19th century. Citing examples from Romantic art and literature, McGilchrist argues that Romanticism embodied the primacy of the right hemisphere.

First, McGilchrist asserts that landscape paintings formed the cornerstone of Romantic art, especially those of Claude Lorrain. Lorrain’s landscape paintings, he argues, were noteworthy for their unique depth, which couldn’t be grasped by the left hemisphere alone; after all, the left hemisphere focuses on minute details rather than the bigger picture. Moreover, McGilchrist writes that like Renaissance perspective paintings, Lorrain’s landscapes show a distinctly human perspective on the world—not the “objective” view that the left hemisphere prefers, but the embodied view that’s distinctive of the right hemisphere.

Apart from art, McGilchrist suggests that Romantic-era literature reveals the right hemisphere’s influence through its expression of melancholy and yearning.

Left Hemisphere Primacy Throughout History

Having seen how the brain’s hemispheres worked together properly across several eras, we’ll now discuss the eras in which this relationship went awry and the left hemisphere exhibited too much power. According to McGilchrist, we can see this imbalance in the Reformation, the Enlightenment, and the Modern and Postmodern world.

Era #1: The Reformation

The first of these periods—the Reformation—occurred as dissenters left the Roman Catholic Church in 16th-century Europe, spawning Protestantism and its many denominations. McGilchrist points to a rejection of metaphor and implicit meaning in religious art to argue that the left hemisphere exerted excessive power over the right hemisphere throughout the Reformation.

To begin, McGilchrist notes that participants in the Reformation often destroyed religious art, such as paintings of Jesus and even crucifix necklaces. They did so, McGilchrist relates, because they thought these art forms were idolatrous, meaning the art itself was an object of worship.

According to McGilchrist, the rejection of religious imagery stems from an inability to grasp metaphor. He argues that, properly understood, religious art is neither divine nor mundane, but rather a metaphor that points to divinity. However, McGilchrist says, Reformers couldn’t understand this because they didn’t understand metaphor—one of the strengths of the right hemisphere. Moreover, he points out that religious art that wasn’t destroyed was often accompanied by a caption that explained it.

Era #2: The Enlightenment

After discussing the Reformation’s religious upheavals, McGilchrist examines the left hemisphere’s influence during the Enlightenment—an intellectual movement in 17th and 18th century Europe that some associate with a rejection of religious dogmas. On the basis of Enlightenment philosophy, he contends that the left hemisphere became too influential during the Enlightenment

To show as much, McGilchrist focuses largely on the work of René Descartes, a 17th-century French philosopher dubbed the father of modern philosophy, arguing that it showcases several hallmarks of the left hemisphere. As McGilchrist points out, Descartes strove for absolute certainty in his reasoning. In turn, he refused to rely on the intuitive, unreflective thinking associated with the right hemisphere, instead attempting to independently confirm these intuitions.  

Moreover, because Descartes wanted to independently verify his intuitions, he took a detached, “objective” stance toward the world that’s neatly aligned with the left hemisphere, as we’ve discussed above. However, this detached view of the world led Descartes to abandon even his own bodily experience, leading him to doubt whether he had a body in the first place. Given the right hemisphere’s preference for embodied existence, McGilchrist argues that Descartes shows a right-hemisphere deficit with this doubt.

In addition to Descartes, McGilchrist also briefly examines English philosopher Jeremy Bentham, arguing that he too reflects the dominance of the left hemisphere. Bentham, McGilchrist relates, was similarly critical of the intuitions favored by the right hemisphere; instead, he took a logic-driven approach to philosophy that led to utilitarianism, a moral system that evaluates actions solely by the pleasure and pain they created. According to McGilchrist, this unintuitive, mathematical approach to ethics is another clear sign of the left hemisphere.

Era #3: The Modern and Postmodern World

After outlining the left hemisphere’s role in the Enlightenment, McGilchrist concludes by discussing the progression from Modernity to Postmodernism around the mid-20th century. Pointing to modernist art, the postmodernist failure to grasp linguistic meaning, and recent rises in certain forms of mental illness, McGilchrist argues that the left hemisphere has again gained undue influence over the right hemisphere.

First, McGilchrist points out that modern art severed the connection between art and the external world, with critics praising the value of “art for art’s sake.” In turn, he says, art grew alienated from the world, leading to abstract artworks that lacked context—exactly what the left hemisphere prefers. According to McGilchrist, this trend yielded several artistic movements that further illustrated the left hemisphere’s influence.

Next, McGilchrist argues that postmodernist views on language also demonstrate the left hemisphere’s primacy. He notes that, in postmodernism, the notion that words correspond to objects in the external world is lost, along with the notion that language can express truths about the external world. As a result, postmodernist views on language fail to grasp the meaning it conveys, instead focusing on the formal structure of language itself—a formal system which, as discussed above, is in the left hemisphere’s wheelhouse.

Finally, McGilchrist cites a rise in mental illnesses associated with right hemisphere deficits as evidence for the left hemisphere’s primacy in the modern world. He points out that schizophrenia became much more common in Western countries during the early 1900s, with symptoms of schizophrenia suggesting severe right hemisphere deficits.

The Cost of Continued Left Hemisphere Dominance

Because the left hemisphere has grown increasingly powerful in the modern world, it’s natural to ask the question: What would happen if the left hemisphere never relinquished its power? In other words, what’s the cost of continued left hemisphere dominance? In this section, we’ll examine McGilchrist’s answers to these questions, first addressing his speculation about the nature of a world dominated by the left hemisphere, then discussing his arguments about the possibility of happiness in such a world. 

What Would a Left Hemisphere World Look Like?

McGilchrist paints a multifaceted picture of the losses suffered in a left hemisphere-dominated world, but we’ll focus on three key losses: the loss of wisdom, the loss of contact with the “real world,” and the loss of meaning.

Loss #1: Losing Wisdom to Knowledge

According to McGilchrist, the left hemisphere’s world would prioritize “knowledge” to the detriment of wisdom, because the left hemisphere’s emphasis on narrower, minute details is incompatible with wisdom’s understanding of the bigger picture. McGilchrist reminds us that the left hemisphere is more detail-oriented, as evidenced by its capacity for selective attention compared to the right hemisphere’s capacity for global attention. The upshot, he contends, is that the left hemisphere’s world would exalt increasingly specialized forms of knowledge. By contrast, the more general wisdom that comes from broad experiences would be seen as less valuable—even illusory, since it can’t be broken down into the concrete details processed by the left hemisphere.

Loss #2: Losing the Real World to the Virtual World

Further, McGilchrist argues that the left hemisphere would prefer the virtual world to the real world because it prefers abstract representations of objects rather than actual objects. He points out that virtual realities are essentially collections of abstract representations, making them attractive to the left hemisphere. By contrast, the actual, tangible objects in the real world are associated with the right hemisphere, making them less attractive to the left hemisphere.

Loss #3: Losing Meaning to a Mechanistic Worldview

Finally, McGilchrist contends that the left hemisphere’s world would see a loss of meaning because it understands the world as a machine devoid of higher value. He reasons that, because the left hemisphere can only process parts rather than wholes, it reduces complicated wholes to mechanistic sets of parts that lack meaning. Such a worldview, he argues, is incompatible with deeper values—such as justice, beauty, and holiness. Consequently, McGilchrist concludes that the left hemisphere’s mechanistic worldview can only accommodate base values, like pleasure and pain.

Happiness in the Left Hemisphere’s World

Though these losses are significant, McGilchrist notes that the left hemisphere might justify them as necessary sacrifices for a greater goal—happiness. In turn, he considers a key question: Would the left hemisphere’s world maximize our happiness? Ultimately, he argues that the left hemisphere’s world would leave us far less happy because it exalts goals such as power and material success that aren’t strongly correlated with happiness.

To begin, McGilchrist points out that the left hemisphere’s inclination toward maximizing utility leads it to focus on generating economic gain. In practice, this means that the left hemisphere seeks to manipulate its surroundings for its own benefit—especially natural resources, whose beauty the left hemisphere cannot understand because it views the natural world as a mere mechanism.

However, McGilchrist argues that this capitalist focus on economic gain isn’t likely to make us happier. To show as much, he points to studies showing that in the US, life satisfaction has actually decreased since the late 20th century, despite economic prosperity increasing sharply. Moreover, he notes that the same is true of Great Britain, whose residents reported higher levels of happiness in the 1950s than they do today, despite being vastly more wealthy. McGilchrist points out that, according to several research studies, happiness is only correlated with salary up to a certain point (about $20,000 USD), after which it plateaus.

By contrast, McGilchrist asserts that our social connectedness is in fact most predictive of life satisfaction, according to researchers. However, forging social connections is a distinct strength of the right hemisphere, with its capacity for empathy and meaningful communication. So, it stands to reason that in a world dominated by the left hemisphere, we would be less happy, as we would struggle to form meaningful relationships.

The Master and His Emissary by Iain McGilchrist: Overview

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Here's what you'll find in our full The Master and His Emissary summary:

  • How pop psychology has given us the wrong impressions of the brain's hemispheres
  • Why the right hemisphere is actually more important than the left
  • What would happen if left-hemisphere thinking took over the world

Elizabeth Whitworth

Elizabeth has a lifelong love of books. She devours nonfiction, especially in the areas of history, theology, and philosophy. A switch to audiobooks has kindled her enjoyment of well-narrated fiction, particularly Victorian and early 20th-century works. She appreciates idea-driven books—and a classic murder mystery now and then. Elizabeth has a blog and is writing a book about the beginning and the end of suffering.

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