The honest answer? “If you join us, the chances are very slim that you’ll end up living in your hometown. You’ll move around from place to place unpredictably, from college to graduate school to postdoc research to professorship, until you’re 40 or so. You’ll be separated from your partner for long stretches of time. You’ll have to wait to have kids, and you may not have them at all. If you do, they almost certainly won’t be able to grow up with their grandparents. But there’s always Skype.”

This dialogue isn’t just hypothetical. Colleagues in the Midwest and the South describe exactly this kind of conversation, and I’ve had similar talks even in cosmopolitan Berkeley. And this discussion doesn’t apply only to scientists. People in many walks of life, across the country and around the world, are having this conversation. It expresses the tension between the global and the local, modernity and tradition, professional opportunity and family ties, the people who leave the place where they grew up and the people who stay.

The strength of Enlightenment Now, Steven Pinker’s new book, is that it articulates the first part of this conversation. Pinker is a psychology professor at Harvard and a wide-ranging public intellectual, and his book is an extended brief for liberal Enlightenment values. He makes his case with masses of data, compelling arguments, and considerable eloquence. At a moment when those values are under attack, from the right and the left, this is a very important contribution.

The weakness of the book is that it doesn’t seriously consider the second part of the conversation—the human values that the young woman from the small town talks about. Our local, particular connections to just one specific family, community, place, or tradition can seem irrational. Why stay in one town instead of chasing better opportunities? Why feel compelled to sacrifice your own well-being to care for your profoundly disabled child or fragile, dying grandparent, when you would never do the same for a stranger? And yet, psychologically and philosophically, those attachments are as central to human life as the individualist, rationalist, universalist values of classic Enlightenment utilitarianism. If the case for reason, science, humanism, and progress is really going to be convincing—if it’s going to amount to more than preaching to the choir—it will have to speak to a wider spectrum of listeners, a more inclusive conception of flourishing, a broader palette of values.

The core of Enlightenment Now is a generic graph, variations of which appear over and over. Each one charts an indisputable measure of human progress—whether it’s more education, peace, and prosperity, or fewer infectious diseases, murders, and even deaths by lightning. To accompany each graph, Pinker provides a summary of scientific data and social-science studies, involving hundreds of thousands of people, spanning human history and extending across the globe. The conclusion, startlingly, is that on almost every measure, things have gotten better and are still getting better. Even that dumpster-fire year 2017 marks an advance over 2016. This pattern of radical improvement began in the 17th and 18th centuries. It accompanied the rise of Enlightenment values in general, and of science and democracy in particular.