Thursday, 27 June 2019

On The Limitations of Human Reason

The Sleep of Reason Produces Monsters
By Francisco Goya
Hugo Mercier and Daniel Sperber are looking at the evolution and working of reason in their book The Enigma of Reason. Here’s an excerpt from the their Introduction to the book:
Human reason is both biased and lazy. Biased because it overwhelmingly finds justifications and arguments that support the reasoner's point of view, lazy because reason makes little effort to assess the quality of the justifications and arguments it produces. Imagine, for instance, a reasoner who happens to be partial to holidays at the beach. When reasoning about where to spend her next vacation, she will spontaneously accumulate reasons to choose a sunny place by the sea, including reasons that are manifestly poor (say, that there’s a discount on the flight to the very place where she would like to go, when in fact the same discount applies to many other destinations as well). 
The solitary use of reason has two typical outcomes. When the reasoner starts with a strong opinion, the reasons that come to her mind tend all to support this opinion. She is unlikely, then, to change her mind; she might even become overconfident and develop stronger opinions. But sometimes a reasoner stars with no strong opinion, or with conflicting views. In this case, reason will drive her toward whatever choice happens to be easier to justify, and this sometimes won’t be the best choice. Imagine she had the choice between visiting her horrible in-laws and then vacationing at the beach, or somewhat cheaper. Reason will drive her toward what seems to be the rational decision: taking the cheaper option. 
I think reason has contributed greatly to our success as a species—it is what makes us special. However, we are really bad at reasoning. We tend to place a greater weight on evidence that supports our existing beliefs, and less weight on evidence that contradict them. More often than not we rationalize to find support for the good or bad choices that we have made in life.

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