Rationality: What It Is, Why It Matters, and Why It Seems Scarce by Steven Pinker

Abstract

In his latest book, Rationality: What It Is, Why It Matters, Why It Seems Scarce, Steven Pinker brings attention to how we might strengthen our reasoning powers, as well as be more cognizant of the ways we might fall short. This mostly takes the form of a wide-ranging tour, acquainting us with various forms of fallacious reasoning as well as tools to improve our reasoning faculties. As a famous professor of psychology at Harvard, Pinker is arguably well-equipped to provide a comprehensive survey on various sorts of cognitive biases and ways of thinking about rationality. The book provides a useful introduction on various tools and models that arguably characterize rational thinking. But as I’ll discuss, despite his considerable knowledge and expository skills, he stumbles in areas where his own motivated reasoning clouds subject matter he is either attempting to explain or dismiss. In the first chapter, he notes that while rationality often appears to be in short supply, he provides evidence for its universality even among hunter–gatherer tribes, with the San of southern Africa being his example. Here, Pinker demonstrates that many of the sophisticated hunting and decision techniques employed by the San suit their goals admirably. But then Pinker pivots toward areas where our reasoning could be flawed in the areas of math, logic, and probability, according to psychologists. And he highlights that even experts in math or probability can succumb like the rest of us. How do we reconcile this with Pinker’s observation of the sophisticated reasoning of hunter–gatherers? Pinker eventually gives us something of an answer toward the end of the book, where he explains that we do much better with the problems we face in our immediate surroundings (and where there are real stakes) than relatively more abstract and remote problems.
Pinker explains that rationality, essentially, is “a kit of cognitive tools that attain goals in particular worlds” (p. 5). Later, he puts it slightly differently as an “ability to use knowledge to attain goals” (p. 36). And for Pinker, knowledge is “justified true belief,” or the things we know confidently that are grounded in facts. Of course, Pinker acknowledges that our quest for truth requires epistemic humility, as perfect rationality and purely objective truth must elude all humans. But we can nevertheless aim to be aware of various rules and models of reasoning that can aid us in avoiding biases that obstruct rationality, and “allow us to approach the truth collectively in ways that are impossible for any of us individually” (p. 41). Much of the book provides a tour of cognitive biases and tools for avoiding them.