The Enigma of Reason

Reason, we are told, is what makes us human, the source of our knowledge and wisdom. But if reason is so useful, why didn't it evolve in other animals? And if it is so reliable, why do we produce so much thoroughly reasoned nonsense? In this ground-breaking account of the evolution and workings of reason, Hugo Mercier and Dan Sperber solve this double enigma. Reason, they argue with a compelling mix of real-life and experimental evidence, is not geared to solitary use. What it does is help us justify our beliefs and actions to others, convince them through argumentation, and evaluate the arguments others address to us. Reason evolved to help humans exploit their uniquely rich social environment, explaining both its strengths and its puzzling weaknesses.

Why You Should Read?

• Offers a provocative new theory that explains why reason is biased toward what we already believe, yet remains indispensable for spreading good ideas.
• Backed by a compelling mix of real-life examples and experimental evidence from cognitive science and psychology.
• Makes sense of long-standing puzzles that have confused philosophers and psychologists for decades.
• Ambitious, entertaining, and accessible — it will make reasonable readers rethink their own thinking.

About the Author

Hugo Mercier is a French cognitive scientist specializing in the evolution and function of human reasoning and argumentation. His research examines how people produce, evaluate, and are persuaded by arguments, and his work has contributed to reshaping debates in psychology and philosophy about the role of reason in human life. He is also the author of Not Born Yesterday, on the science of belief formation and gullibility.

Dan Sperber is a French social and cognitive scientist, renowned for his work in cognitive anthropology and pragmatics. He co-developed relevance theory with Deirdre Wilson and the epidemiology of representations, influential frameworks for understanding culture and communication. His ideas on human cognition and reasoning have shaped research across psychology, linguistics, philosophy, and anthropology.