Rationality is a precious birth­right that we too often take for granted if not mock or reject — despite our supposed sophistication.

Ours is the first age in which humanity’s collective knowledge waits quite literally at our fingertips — yet most of us continue to embrace easily refutable false­hoods with abandon. Ours is a time when higher education is available to almost anyone who seeks it — yet we wear our diplomas alongside garish contempt for the very foundations of learning: intellectual openness, dialogue, and the possibility that we might be wrong. Ours is a world made immeasurably better by the products of a cautious and humble scientific method — yet we invoke “science” as a bludgeon with which to silence the skepticism on which its very progress depends.

People who read and take to heart Steven Pinker’s Rationality will understand those tragedies and be much better equipped to respond to them in their many guises. No book can relieve us of the day-to-day heavy lifting, however, of thinking and behaving rationally in societies that increasingly enable if not reward the opposite. In view of all that conspires against rationality, Pinker seems unduly confident that it will continue to sustain the remarkable progress of humanity’s recent Enlightenment.

Early on, the eminent cognitive psychologist notes that “rationality is not a power that an agent either has or doesn’t have, like Superman’s X-ray vision. It is a kit of cognitive tools that can attain particular goals in particular worlds.” We could imagine it also as a beautifully written textbook. Chapters on logic, probability, Bayesian reasoning, rational choice, signal-detection, game theory, and the concepts of correlation and causation might in different hands be impassable. Pinker makes them page-turners. Accessible charts and graphs share space with funny and often poignant cartoon strips. And he is a generous writer, happy to cite long passages and powerful examples from others who have covered this ground effectively in the past.

Teachers assembling core curricula or “humane” syllabi (if you still exist): Assign this book early in your students’ education. And often. Yes, rationality is an evolutionary and/or — with apologies to the famously nonbelieving professor — God-given birthright, but it is relentlessly undermined by the equally innate cognitive biases and tendencies to reason fallaciously that Pinker describes. Today we recognize our mistakes with a wince and tomorrow we succumb to them completely, so constant reminders help.

To his immense credit, Pinker implicates experts and intellectuals as much as anyone else in this catalogue of irrationality. Indeed, his fascinating account of the San people of the Kalahari Desert establishes them as better able than many a published Ivy League academic to adjust their hypotheses, engage in critical thinking, and ultimately derive rational insights to conserve their environment and way of life. His observations on the widespread misunderstanding of significance-testing among scientists who claim to practice it are among the most sobering passages in the book.

Pinker’s avoidance of contemporary controversies can be frustrating. This book could not be more relevant to the mess the U.S. has made of data analysis and public-health decisions during the pandemic, but Pinker rarely brings up COVID-19. In the case of climate change, he simply takes a pass — dismissing skeptics of the supposedly catastrophic effects of human-caused global warming as anti-rational without ever interrogating them or their accusers. (Ironically, Unsettled, a recent book from one such skeptic, the theoretical physicist and former Obama-administration official Steven Koonin, could be a companion volume to Rationality in its enumeration of the logical fallacies in popular interpretations of climate science.)

If it stops even one person from tossing aside Pinker’s book in tribal disgust, however, then perhaps his hedging is worth it. Rather than being hit over the head with accusations, it certainly is better that we question our assumptions after gazing into this powerful mirror. But will we?

Pinker does not believe that a “post-truth” society is at hand in which objective standards of truth and rational decision-making give way to alternative realities. He takes comfort in the hair-splitting distinction between a post-truth society and a “myside society,” in which “both sides believe in the truth but have incommensurable ideas of what the truth is.” Pinker fails to explain why a residual belief in the notion of truth should reassure us in an environment where both sides (many sides, actually) receive constant, unchallenged reinforcement of “their truths” via dopamine-inducing digital stimuli — and risk devastating personal or professional consequences if they reveal any skepticism of the dominant truths.

Pinker’s definition of rationality — “the ability to use knowledge to attain goals” — points to what a close-run thing the survival of an Enlightenment based on rationality is likely to be. Classical-liberal societies blossomed as none had before them thanks to institutions that posited the existence of objective truth and incentivized the pursuit of knowledge as the surest way to achieve desirable goals. Pinker lists some of these institutions: “peer review in academia, testability in science, fact-checking and editing in journalism, checks and balances in governance, and adversarial proceedings in the judicial system.” But he whistles past a recognition that all of them are weaker and less credible today than they were just a few years ago.

As truth-seeking institutions wobble, ways to “attain goals” through means other than appeals to reason will gain the upper hand. Success inspires imitation. Already, the last two American presidents have demonstrated that alternative facts (“stolen election,” “Jim Crow 2.0”) will do just fine to satisfy today’s political tribes. And why build a case based on truth or principles against an outlying professor, corporate official, or arts-group leader when mostly anonymous digital innuendo can do the job in hours? The guillotine has nothing on the efficiency of today’s ubiquitous cancel mobs.

Professor Pinker is the rare survivor of such a mob, which makes his courage in publishing Rationality remarkable — and his continuing optimism a source of some hope. He gives us the toolkit with which to construct a rational future. May his confidence in its use prove justified.