Many signs point to a sort of “rationality crisis,” or a wave of irrational and weird beliefs assailing us in advanced societies, like a cultural marker of our times. It is not strange that alarms are ringing in several informed media and that new titles try to alert us about the incoming dangers and to advise everyone how to tackle the incoming crisis. Indeed, the popular author Steven Pinker, professor of psychology at Harvard University, is not alone in this well‐intentioned task. At least, two other new books published by academic presses endeavor to pursue a similar program: Nadler and Shapiro, When Bad Thinking Happens to Good People; and Neil Levy, Bad Beliefs. Obviously, the list could be enlarged with earlier books that engaged in this crusade: to convince us about the need to be rational and to avoid the traps and lures of irrational thinking and bizarre beliefs.

Pinker's new book offers an engaging and entertaining approach to instruct people on how to discern what is more rational or how to form our beliefs according to the best evidence and the highest probabilities. In that sense, this is an educational book that would be appreciated even by military officers. The book devotes most of its content to improving our cognitive skills and avoid flawed thinking, biases, and false deductions. It instructs how to prevent the avidity for novelty that nourishes fake news and likely faulty information. However, the book is, among everything else, a passionate assertion of rationality or reason above emotion, intuition, or related fashions that consider reason as too dull and insensitive. It is clearly linked to Pinker's former project Enlightenment Now (2018), an essay that vindicates the legacy of modern thinking on the power of reason over tradition and nonjustified beliefs, to ensure humanity's progress.

This new project develops the case for rationality in 11 chapters. Two introductory chapters explain what it means to be rational, showing how easy it is to fall in biases and cognitive mistakes, and how pervasive irrational thinking can be, even in putatively well‐informed people. The body of the book is devoted to training our mind in exercises and practices that could improve our rational skills: logic and critical thinking; probability and randomness; evidence of beliefs or Bayesian reasoning; rational choice and expected utility; signal detection and statistical decision theory; game theory; and the need to discern correlation and causation. All this should contribute to right decision‐making for everyone.

The last two chapters come back to campaigning for the cause, explaining why many people hold irrational beliefs and what to do to improve things. These chapters offer a theory about levels of reality, and the distinction between rational and mythologically generated thinking. Recent views in cognitive psychology assist the author to better understand why people acquire such misleading beliefs; an analysis that gives place to an implicit teaching on how to avoid these cognitive traps. Religious beliefs come often in these pages together with imagined or mythical views and fake news. Indeed, biased news have more viewers than politically middle‐of‐the road news. Pinker argues that we need to focus harder to get some more logical and statistical formation, and to be more attached to reality, and less to fantasy in order to overcome all that plagues our understanding. The last chapter emphasizes the advantages of rationality for our daily lives and for long‐term planning to make better decisions. It reminds one of a self‐help text or even a personalized advice to avoid foolish investments and to better manage our own future. The medical and juridical fields would benefit from that approach, even if they are intended to be already rationally based. For all this, well‐informed rational thinking, assisted by logic and statistical means, will become an invaluable ally. Pinker concludes by stating that moral progress is due to rational arguments, even if this is certainly not the only relevant factor in a long history of moral development.

For many readers, the book will suggest the syllabus of a course in logic, statistics, and decision theory, all combined to better fit the expected goal to render all of us more rational and balanced. It assumes a rather procedural idea of rationality: what is more important is to learn to think in the right way. A general impression is that Pinker takes for granted the hard issues regarding the goals or ends, and he is looking rather for the right means. Actually, the big issue about how reason assists to better determine such goals seems absent: which are the great objectives and meanings for humanity and for each person? Perhaps just striving to survive and reproduce? Being happy? Living an accomplished life? Being honest and helpful? Or being faithful to a religious creed?

The issue of reason has been at the center stage in the history of philosophy at least since the time of the great Greek classical thinkers; indeed, for many of them, reason was the paramount requirement to live a good life. The Western Christian tradition has followed that pattern, as can be seen in most Medieval thinking. Moderns have inherited this rational approach and have tried to improve and better apply reason to all social settings. Pinker is right in vindicating this human feature and recognizing its central role when trying to describe current difficulties and cultural troubles. However, I find less convincing that just resorting to a procedural approach we will be able to address the described problems, even if the suggested ways will help.

Many questions still arise. To start with, reason and rationality are much more complex issues. The old philosophical discussion regarding reason implies that there is more than the approach Pinker tries to expound. Rationality comes indeed in several versions in modern times, involving even the scientific inquiry: pragmatic, instrumental, consensual, factual, bounded… to quote just some among familiar ones. Then a second issue: this and the other quoted books are less about reason and more about beliefs and believing. The real issue is the processes by which we form beliefs and how we can distinguish between useful and not useful beliefs (not just true or false), a not so easy task with clear ethical implications. Reason and Bayesian calculus can help to some extent, yet those who study the process of believing do advise that such study is likely to reveal the great complexity of that mental activity.

Third is the question about religious beliefs. Pinker's approach is, to say the least, rather simplistic and quite flawed. For those used to the depth of contemporary philosophy of religion or the recent discourse on religion and science, this book will come across as dismayingly naïve and disappointing, especially on account of conflating some religious beliefs with irrational claims or opinions for which there is but scant evidence. Pinker seems unable to recognize that Christianity and other religions have been harbingers of rationality during a long history, together with being originators and propagators of supernatural religion‐specific myths and counterintuitive and counterfactual beliefs. However, he neglects to observe how the Enlightenment and modern secular ideologies, and even science at times, have nourished many powerful myths, which have caused enormous confusion and suffering. The reality is that we cannot rely on pure reason alone or avoid holding beliefs built on poor epistemological evidence to live our lives. Just ask any mother. In other words, even if it plays an important and unavoidable role, reason is not enough in life. And so, learning to believe is still an urgent task, to which traditional religions with a long practice in believing could contribute to improve things. Theologians have here a great responsibility and a role to play together with philosophers and other experts besides scientists.