I loved Steven Pinker’s previous book, Enlightenment Now, which I reviewed here. There were parts of it that made me want to jump up and cheer.

So I was eager to read his latest, Rationality: What It Is, Why It Seems Scarce, Why It Matters.

What a disappointment!

If you’re not familiar with him, Steven Pinker is the Johnstone Family Professor of Psychology at Harvard University. He’s probably best known for his research on language acquisition by children. He’s also become a somewhat controversial public intellectual. Rationality is his twelfth book.

Cover of Rationality

By Steven Pinker
Viking, New York, 2021

I’ll frame this review around the three questions in the subtitle of the book.

What is rationality?

Pinker defines rationality as “a kit of cognitive tools that can attain particular goals in particular worlds.” [p. 7]

The goals we achieve via rationality can be theoretical, to figure out if something is true or not, or practical, to figure out how to produce some outcome in the world. We do this by applying knowledge, including contextual knowledge of our current surroundings and circumstances.

Why does rationality seem scarce?

Despite being the most intelligent species on the planet (or so we claim), humans are often laughably bad at critical thinking, assessing risks, adjusting our beliefs when we receive new information, and understanding the difference between correlation and causation.

And despite living in the most scientifically and technologically advanced period in human history, many of us believe all sorts of ridiculous nonsense (astrology), absurd conspiracy theories (Covid vaccines contain microscopic 5G cell phone chips), and outright lies (the 2020 US presidential election was “stolen” from Donald Trump).

So why does rationality seem scarce?

Pinker’s answer is that the cognitive tools in our kit need sharpening. He spends the bulk of the book, seven chapters, attempting to remedy this by delivering short courses in critical thinking, probability, rational decision-making, game theory, correlation and causation, and other topics. Can’t fault the man for lack of ambition, but it’s this part of the book I found so disappointing.

Each of these chapters starts with a litany of common mistakes, such as the gambler’s fallacy — eventually your number will come up — in the chapter on probability. There’s a lot of “people think this …” or “people believe that …” and, oh my, aren’t we stupid. Much of this is drawn from the pioneering work of Daniel Kahneman and Amos Tversky. Pinker then dives into detailed explanations of the theory and often the mathematics of how we should be thinking.

Now, I have some basic familiarity with most of these topics and I normally find them quite interesting. Unfortunately, I found Pinker’s presentation either incredibly soporific or confusing as hell. In the chapter on critical thinking, for example, Pinker reviews the rules of formal logic, also known as propositional calculus. It’s irredeemably dull. The chapter on correlation and causation has a section on the important idea of statistical significance that left me bewildered. Reading the chapter on Bayesian inference was like wading through mud.  

Pinker does try to show how the particular techniques of each chapter can be applied to real world problems, but often his examples or his presentation were too dry or too academic to revive my interest. One good example, though, was his look at the criminal justice system. Pinker suggests that more emphasis on distinguishing signals from noise in the evidence could have a greater effect on reducing both wrongful convictions and wrongful acquittals than endless debates about how tough we should be on crime.

If Pinker’s goal in this part of the book was to equip us with as set of practical, applicable cognitive tools, he failed, at least for me.

Why does rationality matter?

The last two chapters address this question, and in my opinion they’re the strongest part of the book. They also repeat many of the ideas from Enlightenment Now.

Pinker’s argument is that rationality is necessary for both material and moral progress.

Material progress, he argues, is achieved by solving problems and by the continual accumulation of knowledge gained by doing so. This enables us, for example, to develop Covid vaccines within a year of the disease first being identified. He calls vaccines “the most benevolent invention of our species.”

Moral progress also depends upon rationality. We no longer stone people to death or burn heretics at the stake. Slavery has been abolished worldwide. Most people no longer regard war as a noble or glorious endeavor. These things seem obvious to most of us now, but as Pinker points out, they weren’t obvious in the past. Someone, some people, had to make these arguments … using rationality.

Pinker isn’t suggesting that we’ve made sufficient material or moral progress. On the contrary. We have a long way to go, but what enables us to progress is rationality.

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Rationality contains flashes of the wit and brilliance that I enjoyed so much in Enlightenment Now, but not enough to rescue the book.

It’s too bad because rationality does matter. Humanity faces enormous challenges now and in the coming decades. There aren’t clear answers. We need open, constructive, and yes, rational debate to develop the best approaches. That means we need more people to become more skilled with the tools of rationality. I think Pinker has the right intentions here and I fully agree with his call for and defense of rationality. I only wish he had delivered a clearer, more engaging book.

Pinker makes an interesting point that, from a historical perspective, it’s a radical idea that everything should have a rational explanation. In fact, throughout most of human history, there were virtually no rational explanations for anything. Instead, we made up myths.

“Submitting all of one’s beliefs to the trials of reason and evidence is an unnatural skill, like literacy and numeracy, and must be instilled and cultivated.” [p. 301]

I agree. If you’re looking for a more useful and practical toolkit to enhance your reasoning skills, I suggest the late Hans Rosling’s book Factculness (review). And for critical thinking skills, you might check out Calling Bullshit by Carl Bergstrom and Jevin West (review).

Thanks for reading.

Related Links

Pinker’s progress: the celebrity scientist at the center of the culture wars
Profile in The Guardian, Sept. 28, 2021

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2 Responses to Rationality

  1. Good to see your review here. I really enjoyed Enlightenment Now as well as The Better Angel of Our Natures, but they were both quite an investment of time. So I’ll pass on buying Rationality based on your review. Maybe I can just borrow it from the library sometime in the future.

    Liked by 1 person

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