Steven Pinker Thinks Rationality Is Unnatural, But...

Almost three decades have passed since Steven Pinker published The Language Instinct. In that book, Pinker systematically addressed the evidence against the idea, once popularized by B.F. Skinner, that language, like playing Mozart on the piano, had to be learned, step by step, via parental administration of rewards for progressive approximations (no, it's "ball," not "bah"). Pinker made a strong case that, when it comes to speaking, we are born little Mozarts, with brains prepared to effortlessly absorb whatever language our parents happen to speak, and to naturally re-arrange those words into understandable, syntactically complex, and even artistically clever new sentences.

In another well-written, easily understandable, and scientifically rigorous book, Enlightenment Now, Pinker argued that, looked at over the long span of history, human life is getting better in almost every way (see “Ten Ways the World Is Getting Better”).

In Pinker’s most recent book, Rationality, he is a little less sanguine, noting that “covid quackery, climate denial, and conspiracy theories” along with “fake news” have led some experts to worry that we are in an “epistemological crisis,” and others to declare that we’re living in a “post-truth era.”

Unlike speaking, Pinker does not believe that logical thinking comes naturally and effortlessly. He admits that, during recent decades, while there has been great progress in addressing poverty, illiteracy, and disease, there has not been clear progress in indices of rational scientific thinking.

Indeed, he opens his first chapter with a less-than-optimistic quote from the philosopher Bertrand Russell:

Man is a rational animal. So at least we have been told. Throughout a long life I have searched diligently for evidence in favor of this statement. So far, I have not had the good fortune to come across it.

But although thinking clearly, like playing classical piano, requires dedicated practice, and is easy to forget, Pinker makes a strong case that it is possible. When we are motivated to do so, human beings can be incredibly logical and thorough in their thinking, and Pinker describes how the San foragers of the Kalahari dessert exercise a keen scientific mindset when they are hunting for their dinner—logically ruling out alternative hypotheses as they try to determine whether a set of footprints belongs to a young and agile female springbok or a tired old male eland antelope.

Rationality seems to have started from Pinker’s notes for a class he teaches to Harvard students. Over the course of the book, he presents a set of lessons we would all benefit from weaving into our everyday lives. There are chapters on logic, probability and randomness, Bayesian reasoning (updating our hypotheses based on evidence), rational choice and expected utility, signal detection (distinguishing hits from false alarms), game theory, and an expanded treatment of the distinction between correlation and causation. If you’ve read Pinker’s earlier books, you will not be surprised to hear that he covers this vast intellectual territory effortlessly, offering a continual stream of clear, entertaining, and often humorous examples of rational and irrational thinking.

I ought to know a little about these topics, having read and taught about them, written an article on “Antiscience Thinking” for Scientific American, and even co-authored a book titled The Rational Animal (see “The Evolved Wisdom Behind Our Seemingly Stupid Decisions”). But I say "ought to" because I am always humbled by the magnitude of my ignorance, and I learned a lot from Pinker’s book. It smoothly integrates ideas from diverse perspectives on rationality, and connects them to many of the problems we (and our sometimes feckless leaders) have processing information in the modern world. I intend to read it again, and I hope those leaders, and their followers, will too.

Is there hope for a more rational future?

Despite arguing that rational thinking does not come naturally, and admitting the many current irrationalities offered up by truth-denying politicians and internet conspiracy theorists, Pinker ends the book on a hopeful note. He points out numerous ways in which scientific thinking since the dawn of the enlightenment has led to real progress and the near eradication of superstitions people once took for granted (such as believing that changes in the weather were the work of witchcraft). In his final chapter, he notes the many costs of irrational thinking (such as deaths from those who believe quacks rather than medical experts, and domestic terrorists misled into violence by truth-warping political leaders). He quotes passages from John Locke, Mary Astell, Frederick Douglass, and Martin Luther King, Jr., all of whom used rational argumentation to bring about radical social changes, such as women’s right to vote, and the abolition of human sacrifice and slavery.

For years, evolutionary psychologists were criticized for being too focused on the negative aspects of human behavior. Pinker is now sometimes accused of being too optimistic. Is it irrational to hope he’s right in arguing that the arc of rational thinking, though long, will continue to bend toward progress? Read his book, and decide for yourself.