As with “The Bell Curve,” we will have to wait for peer reviews to carefully sift through the science. Early indications might indicate some trouble for Murray. Last month, the psychologists Michelle N. Meyer, Patrick Turley and Daniel J. Benjamin issued a sharp rebuke to his use of their research on polygenic scores in his piece for The Wall Street Journal teasing the new book. He characterized polygenic scores as providing decisive insight into I.Q. that was “impervious to racism and other forms of prejudice.” In fact, the psychologists assert in response, “polygenic scores can and do reflect racism, sexism or other prejudices, as well as more benign environmental factors.”

Murray serenely rolls out his propositions, assuring us on occasion that it is all “consensus,” “securely known.” And yet several claims are plainly contentious, even to the lay reader. Take Murray’’s description of male brains as “systemizers” and female brains as “empathizers,” drawing on work of the psychologist Simon Baron-Cohen. Men are drawn to things, in other words, and women to people. (You’ll recognize this terminology from James Damore’s diversity letter to Google.) This rubric becomes an organizing principle in the book, explaining the typically gendered vocations for men and women (Things Jobs and People Jobs). What Murray avoids discussing are the profound questions surrounding one of the studies that scaffold his thinking.

In 2000, Baron-Cohen and colleagues published a study of day-old babies that found that boys looked at mobiles longer (hence “systemizers”) and girls at faces (“empathizers”). This study has never been replicated, not even by Baron-Cohen. It was also poorly designed: for one, some of the newborns were propped up; their gaze might have been mediated by how they were held. Not to mention the core question, as posed by the psychologist Cordelia Fine, who has written extensively about bias in research on sex differences in the brain: “Why think that what a newborn prefers to look at provides any kind of window, however grimy, into their future abilities and interests?”

Or consider Murray’s interpretation of why women haven’t branched into more male-dominated fields over the last 30 years. Once again, he finds an explanation in the female preoccupation with people and emotion as opposed to the male orientation toward things and abstract thought. Sexism cannot be the culprit, he claims. Now that outright prohibition of women entering male-dominated fields has ended, any vestigial opposition ought to have abated in “a matter of years.” Never mind the wealth of research showing the very real persisting impediments that Murray dismisses. To name just one well-known example: In a study at Yale University, over 100 scientists reviewed a résumé submitted for an open position. The résumés were identical, although half were submitted under men’s names and half women’s names. The women’s résumés were ranked significantly lower than the men’s — by both female and male faculty.

Why doesn’t Murray attend more thoroughly to the role of the environment, to history — even if to decisively repudiate their impact? On genetics, too, he dismisses aspects that might dilute the strength of his argument that outside interventions are limited in their effects on personality and social behavior. Developments in epigenetics, for example — outside mechanisms that effectively turn genes “on” or “off” — are waved away as “hype.”

Stranger still are the inconsistencies. “Race is a construct” is among the tenets Murray seeks to dismantle. Yet tucked midway through the book is the bland assertion that his evidence does not “deny the many ways in which race is a social construct.” There is no genetic basis for race. It is a social and legal definition — a young, crude one at that, overlaid on the tangled realities of ancestral heredity. “Ancestral populations” might be more apt, he concedes. Not 40 pages later, however, he’s back to huffing at the “elite wisdom” that “race is a social construct.” Murray appears to want it both ways: to gesture at a more nuanced and precise formulation but also to harness, when he chooses, the raw rhetorical power of railing against woke dogmas about race.