Seven Deadly Sins: The Biology of Being Human by Guy Leschziner offers a fascinating exploration of humanity’s most infamous vices. Using a blend of neuroscience, psychology, and history, Leschziner investigates the evolutionary and biological roots of wrath, gluttony, lust, envy, sloth, greed, and pride. More than a moral inquiry, the book questions whether these vices are moral failings or simply intrinsic aspects of our humanity.
With a writing style both erudite and accessible, Leschziner’s work is part philosophical treatise and part clinical memoir, enriched with patient stories and historical anecdotes. However, while the book is an ambitious attempt to unravel the human condition, it is not without its flaws.
Overview of the Seven Deadly Sins
Leszcziner structures his book around the titular sins, dedicating a chapter to each. The chapters serve as both historical retrospectives and modern analyses, framed by personal patient stories that anchor the theoretical discussions in real-life experiences. The book’s central thesis is that these sins are hardwired into us for evolutionary reasons and that they have dual roles—both as destructive forces and as drivers of human progress.
Strengths: An Intricate Weaving of Neuroscience and History
Leschziner’s ability to interlace scientific explanations with historical context is among the book’s greatest strengths. For instance, his discussion of wrath dives into its evolutionary underpinnings, linking the survival advantage of anger in prehistoric societies to its pathological manifestations in modern life. The narrative extends to patient stories, like Sean’s, a man whose epilepsy triggered uncontrollable outbursts of violence. These stories illustrate how neurological disorders can “unmask” sins, turning theoretical concepts into visceral realities.
Similarly, in his chapter on lust, Leschziner elegantly navigates the hormonal and neural mechanisms behind attraction and infidelity while contextualizing them within cultural taboos. His insights on how gluttony ties into brain chemistry and the modern food environment are particularly compelling. He connects the neural systems governing appetite to the obesogenic society we inhabit, creating a narrative that feels timely and relevant.
Critiques: Uneven Pacing and Overreliance on Patient Narratives
While the patient narratives provide a humanizing lens, their dominance occasionally overshadows the broader scientific and philosophical arguments. For instance, the chapter on sloth spends excessive time detailing a single patient’s struggles, leaving less room for a broader exploration of how evolutionary biology defines laziness as a survival mechanism.
Additionally, the pacing can feel uneven. Some chapters, like those on greed and envy, are densely packed with insights and thought-provoking analysis, while others, such as sloth and pride, lack the same depth. This imbalance detracts from the cohesion of the work, making some sections feel overly anecdotal and others overly academic.
A Balancing Act: Moral Philosophy Meets Science
One of the most intriguing aspects of the book is its attempt to reconcile moral philosophy with modern neuroscience. Leschziner’s perspective that the sins are evolutionary byproducts—neither inherently good nor evil—challenges traditional theological views. He suggests that these traits evolved to ensure survival and social cohesion, a stance that blurs the line between morality and biology.
For example, the discussion of envy highlights its dual nature: as a destructive emotion that fosters resentment and as a motivator that spurs ambition. Similarly, pride—often condemned as a sin—is framed as essential for self-esteem and social standing. These reinterpretations make the reader question long-held beliefs about virtue and vice.
However, this balancing act is not always successful. At times, Leschziner’s scientific explanations overshadow the philosophical implications, leaving certain moral questions unresolved. For example, while the book deftly explains the neurological basis of lust and its evolutionary advantages, it sidesteps questions about its societal consequences, such as the ethical implications of infidelity.
Writing Style: Accessible but Occasionally Repetitive
Leschziner’s prose is engaging, often veering into poetic territory when describing the complexity of the human brain. He has a knack for making dense scientific concepts accessible, using metaphors and analogies that resonate with lay readers. For instance, his description of the brain as a “constellation of competing drives” brings the abstract to life.
However, the book’s readability is occasionally marred by repetition. Certain points—such as the evolutionary benefits of the sins—are reiterated across multiple chapters, diluting their impact. This redundancy might frustrate readers seeking a more streamlined narrative.
Themes and Key Takeaways
1. The Biological Basis of Morality
A central theme is the idea that morality is deeply intertwined with biology. Leschziner argues that the seven sins are not just cultural constructs but reflections of our neural wiring. This perspective shifts the narrative from moral condemnation to understanding, suggesting that sins are part of what makes us human.
2. The Dual Nature of Sin
Each sin is explored as a double-edged sword—capable of both harm and benefit. Wrath, for instance, is shown to fuel violence but also to protect and motivate. Greed drives societal inequality but also innovation and progress. This nuanced approach encourages readers to see these traits as evolutionary tools rather than purely moral failings.
3. The Role of Free Will
The book raises profound questions about free will, particularly in the chapter on pride. If our sins are rooted in our biology, to what extent are we responsible for them? Leschziner’s exploration of this question is both provocative and incomplete, leaving readers to grapple with the implications.
Comparison to Similar Works
Seven Deadly Sins can be compared to books like Behave by Robert Sapolsky and The Righteous Mind by Jonathan Haidt. Like Sapolsky, Leschziner delves into the neuroscience of behavior, though his focus on individual case studies sets his work apart. However, Leschziner lacks the narrative cohesion of Haidt’s moral psychology, making his book feel more fragmented in comparison.
Conclusion: A Thought-Provoking but Imperfect Exploration
Seven Deadly Sins is an ambitious and enlightening work that blends science, history, and personal narrative to explore the biology of human behavior. Leschziner’s insights into the neural and evolutionary roots of morality are both fascinating and accessible, making complex ideas digestible for a broad audience.
However, the book’s uneven pacing and overreliance on patient stories detract from its overall impact. While it excels in framing the sins as evolutionary imperatives, it occasionally falters in addressing their societal and ethical ramifications.
For readers interested in neuroscience, psychology, or moral philosophy, Seven Deadly Sins offers a compelling, if imperfect, exploration of what it means to be human. It challenges us to rethink morality, not as a rigid dichotomy of right and wrong, but as a spectrum shaped by biology, history, and culture.
Final Verdict
Seven Deadly Sins is a thought-provoking read that offers profound insights into human behavior but falls short of delivering a cohesive and balanced narrative. While it may not satisfy readers seeking definitive answers, it succeeds in sparking curiosity and encouraging reflection on the complexities of morality and the human condition.
