Charles Murray’s new book, Human Diversity, provides a summary of what is known about human difference and an essential message for how our politics should address that difference. It offers the layman a snapshot of today’s progress in describing the genetic wellsprings of human diversity. Simultaneously, it argues that this progress should not disturb the American creed of equality before the law. Murray encapsulates the relevance of this foundational principle to his work: “Equality is not the empirical claim that all groups of humans are interchangeable; it is the moral principle that individuals should not be judged or constrained by the average properties of their group.” Yet it is a mark of the decline of our commitment to this ideal that this book is sure to be assailed, particularly on college campuses. There the mantra of diversity claims that groups, like men and women, are interchangeable (even though certain individuals are regularly denied equal treatment, as when their membership in a group puts them at a disadvantage in faculty hiring or student admissions).

The book is divided into three parts. The first shows that men and women are indeed not interchangeable: they have on average somewhat different innate cognitive strengths and emotional affects. The second argues that subpopulation groups have some inherited differences on average. Race, according to Murray, is not merely a social construct. The third argues that intelligence has a substantial inheritable component that shapes social class and is very difficult to change through government policy.

This review focuses on the first section because it is the richest and most comprehensive part in its conclusions. Of course, most of us recognize that men and women are not the same. And if men and women did not differ somewhat in their inclinations and conduct, they would constitute a singular exception to the behavior of males and females throughout the animal kingdom. Nevertheless, a form of gender egalitarianism today does indeed assert that, except for differences that cannot possibly be ignored (like the ability to carry a child to term), men and women have no innate differences that are relevant to their average abilities, aspirations, and behavior.

Murray summarizes the wealth of emerging evidence from biology and psychology to show that this claim is false. First, on average men and women diverge in the kind of intellectual abilities at which they are most likely to excel. As Murray emphasizes, that does not mean the men are more intelligent than women or vice versa. Indeed, they score on average almost the same on I.Q. tests. But on average (and it is always essential to remember we are talking about averages), they differ in their intellectual strengths. As Murray puts it, “On average females have advantages in verbal ability and social cognition while males have advantages in visuospatial abilities and the extremes of mathematical ability.” In other words, men generally possess stronger innate skills for the manipulation of things, while women possess stronger skills for understanding people. Thus, for instance, women score better on reading narratives and men better on visuospatial tasks.

The people versus things dichotomy is evident from early childhood. For instance, a 2002 study showed, according to Murray, that “newborn girls no more than two days old showed stronger interest in a human face while newborn boys showed stronger interest in a mechanical mobile.”

Men and women also allocate their time in a way that reflects this people-things dichotomy. Synthesizing various studies, Murray concludes that “on average, women worldwide are more attracted to vocations centered on people and men to vocations centered on things.” So women prefer on average to spend more time on family and community service. They are also more risk-averse. This, he notes, is true even of women with genius-level I.Q. at times when careers are open to both men and women. As Murray emphasizes, this difference in preferences does not mean that their life choices are better or worse than males. There are many ways to shape a flourishing life.

As a result of these innate differences, men and women left at liberty will not choose the same careers in the same proportions. Indeed, Murray makes the striking observation that the more gender equalitarian an industrial society is, the fewer women choose to practice in STEM fields, among those with the skills necessary for achieving success. As Murray notes, this is not surprising if there is an inborn female tendency to be drawn to people-oriented fields: “as national affluence and economic security increase more women will choose fields that correspond to their interests than STEM fields that offer higher job security and income.”

This analysis shows that explaining the relative proportion of men and women in various professions is more complicated than a simple story of discrimination. To be sure, as Murray acknowledges, until the 1960s many professions were effectively closed to women. But then women entered. It simply does not follow that their failure to reach numerical parity in some of these professions is still the result of discrimination if women on average differ innately from men in type of abilities and in inclinations.

Our higher educational institutions could do a great service if they helped our younger generation understand these facts. Becoming an educated person today requires instruction in the fascinating complexities of a social world created by beings who are shaped by their biology. That means understanding that women and men can on average be equal in intelligence overall even if they are on average unequal in some different cognitive abilities. And it means understanding that generalized observations about groups based on averages do not translate into determinative conclusions about individuals: even if women are not as strong as men in some cognitive areas on average (and vice versa), many women are far more talented in subjects that require mental rotation of shapes than the average man. And finally, it means understanding that intelligence is not the only determinant of men’s and women’s career choices. Innate inclinations matter too, but once again this is a matter of averages and there is a great deal of overlap. But sadly, all these nuances are lost in universities committed to gender egalitarianism. The atmosphere in higher education contributes to terrible simplifications at the expense of deep understanding.

Murray is optimistic that the intellectual establishment, including our universities, cannot maintain its denial of the innate diversity in human nature for much longer. In the last chapter of the book, he argues that science is now pinpointing the contributions of genes to various human traits. To be sure, the process is itself complicated, because very few traits are determined by a single gene. Instead, thousands or even tens of thousands of genes make small contributions to raising or lowering inherited components of our nature like height or I.Q. But scientists are already using polygenic scores to measure traits. These scores look at the various alleles (alternative genes at a site) that are related to a trait and provide an overall measurement of the genetic contribution. Thus, in an example provided by Murray, if there were 20 genes that contributed to higher height (there are actually thousands more) and you had 9 of these genes, you would have a score of 9 out of 20 in the simplest version of a polygenic score. In reality, scores are more complicated in part because some genes matter more to a trait than others. Ultimately, Murray foresees such scores arraying themselves on a bell curve, just like most human traits, including height and I Q.

Once polygenic scores are available, Murray believes they will be a gold mine for social science researchers who can then show more clearly the genetic contribution to social patterns, whether it is social class or the divergent proportions of men and women in different professions. He is probably right, but this reemergence of a science of human nature will be a long time coming because early researchers will face career penalties and social hostility from censorious senior colleagues and woke students.

Murray’s book makes this father of a four-year-old daughter more anxious in the interim. Like any parent, he believes that his daughter is talented and wants the best for her. Unfortunately, Murray’s book shows that she is likely to receive the wrong signals from schooling and the mainstream media. They will urge her to pursue STEM fields if she has the requisite math and science abilities, regardless of whether her other talents, like that for writing, are greater or even if her natural inclination is for a more people-centered life. In the past, societal discrimination prevented women from entering the fields that were best for them. But today gender egalitarianism discourages the best choices and may sacrifice the individual at the altar of a false collective ideal.