The faculty "doesn't work like we want it to." Review: The Enigma of Reason by Hugo Mercier and Dan Sperber

Reason is more likely to confirm things that we want to be true, or which we already believe. So why does it exist? A new book provides the answer
June 20, 2017
The Enigma of Reason by Hugo Mercier and Dan Sperber (Allen Lane, £25)

Reason is the faculty through which we make logical sense of the world, and is a central part of what makes us human. This has been the settled position of many great thinkers over the centuries: the 17th-century philosopher René Descartes, to name just one. It is troubling, therefore, to discover that “reason” doesn’t work in the way we might want it to.

As the cognitive scientists Hugo Mercier and Dan Sperber argue in their new book, The Enigma of Reason, far from guiding us reliably towards truth, reason can actively lead us away from it. Multiple experiments have shown that despite its pretension to neutrality, it is more likely to confirm things that we want to be true, or which we already believe.

So should we despair? This is where Mercier and Sperber break with their peers, who have struggled to find any useful role for the faculty. According to the authors, though, reason does its job rather well—it’s just a different job from the one we thought it did.

Reason, they stress, must have developed through evolution. Seen through this prism, it is not aimed at guiding us towards truth; rather it serves a social purpose. What our ancestors needed was the ability to win arguments, in order to clinch the top spot in a brutal social hierarchy. The strategies of reason gave them a way of doing so.

The authors’ achievement is in providing a plausible explanation for reason, when for decades cognitive scientists have worried it has none. Their answer, though, isn’t an especially comforting one.

And, after all, reason is only one among many wondrous human faculties. Our capacity for love and for friendship are arguably as important as reason in shaping our worldviews.