The Enigma of Reason

Written with Dan Sperber

Reason, we are told, is what makes us human, the source of our knowledge and wisdom. If reason is so useful, why didn’t it also evolve in other animals? If reason is that reliable, why do we produce so much thoroughly reasoned nonsense? In their groundbreaking account of the evolution and workings of reason, Hugo Mercier and Dan Sperber set out to solve this double enigma. Reason, they argue with a compelling mix of real-life and experimental evidence, is not geared to solitary use, to arriving at better beliefs and decisions on our own. What reason does, rather, is help us justify our beliefs and actions to others, convince them through argumentation, and evaluate the justifications and arguments that others address to us.

In other words, reason helps humans better exploit their uniquely rich social environment. This interactionist interpretation explains why reason may have evolved and how it fits with other cognitive mechanisms. It makes sense of strengths and weaknesses that have long puzzled philosophers and psychologists―why reason is biased in favor of what we already believe, why it may lead to terrible ideas and yet is indispensable to spreading good ones.

Ambitious, provocative, and entertaining, The Enigma of Reason will spark debate among psychologists and philosophers, and make many reasonable people rethink their own thinking.

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Mind & Language: multiple review, and our response.

Teorema: précis, comments, and our response (Spanish version).

Academic reviews by Darren Frey, Bryon Cunnigham, Umut Ungan, Brian Boyd, Paul D’Ambrosio, Derek Anthony Elliott, Ladislav Koreň, Matias Osta Velez, David Grčki, and Edmund Howe.  


"Brilliant, elegant and compelling ... turns reason's weaknesses into strengths, arguing that its supposed flaws are actually design features that work remarkably well ... A timely and necessary book" 

Julian Baggini, Financial Times

"Reason is more likely to confirm things that we want to be true, or which we already believe. So why does it exist? This book provides the answer" 

Alex Dean, Prospect

“Especially timely as we struggle to make sense of how it is that individuals and communities persist in holding beliefs that have been thoroughly discredited.”

Darren Frey, Science

“Reasonable-seeming people are often totally irrational. Rarely has this insight seemed more relevant…Still, an essential puzzle remains: How did we come to be this way?…Cognitive scientists Hugo Mercier and Dan Sperber [argue that] reason developed not to enable us to solve abstract, logical problems…[but] to resolve the problems posed by living in collaborative groups.”

Elizabeth Kolbert, New Yorker

“The best thing I have read about human reasoning. It is extremely well written, interesting, and very enjoyable to read.”

Gilbert Harman, Princeton University

“As evolutionary psychologists, Mercier and Sperber ask what might have been adaptive for our ancestors and thus built into our brains. Some have argued for modules specialized for reasoning about particular topics. But Mercier and Sperber argue for a single module that can frame an argument and its conclusion: the former aids cooperation and the latter communication. So, the ultimate goal of reasoning is persuasion. It’s an extraordinarily ambitious theory presented with brilliant insights, profound scholarship, and entertaining anecdotes.”

Philip Johnson-Laird, Princeton University


The essence of human reasoning 


RSA event 

TEDx Ghent

Science, santé, confiance : pouvons-nous compter sur la raison ?


Cerveau et Psycho

On Thinking

Collective wisdom



The New Yorker

The Guardian (best book of 2017 list) 

Financial Times 


The Times

The WIre

The Current



The Guardian podcast

Radio Canada

New Humanist

USA Today

Folha de Sao Paulo


Big Think



Monkey Cage





Five books


France Culture

Le Monde

Le Soir

Philosophy Now



The New York Times (and also here) (with a clarification here and a blog post here)

The Guardian

New Scientist (cover story)

Corriere della sera

Boston Globe (and on their blog, brainiac)


The Skeptic

Counterpoint (Australian radio)

Wired blog (and also here)

Le Monde blog

Psychology Today blog

Discover magazine blog

The Globe and Mail blog

The Chronicle of Higher Education blog (and here)

Chosun blog

Helsingin Sanomat blog

Big Think(and here)

Bloggingheads (also here and here)

3quarksdaily (and here)

Maui News

Scientific American blog

The Wilson Quarterly


Big picture Science

Point of Inquiry

Philosophy bytes

The Atlantic blog

The Atlantic

You Are Not So Smart

De Standaard