As a liberal who grew up near California’s Bible Belt in Orange County, I was brought up to believe that the enemies of reason were the Christian creationists who taught that the world is 6,000 years old and that biologists can’t explain the evolution of complexity without invoking a divine creator.

While I still believe creationists are wrong, I have come to see their progressive academic counterparts as a bigger problem. I’ll call them the New Creationists. They use Darwin as a bludgeon against the old creationists, but then reject scientific conclusions when they conflict with their political convictions.

For example, there is more skepticism on the political left about the safety of vaccines and genetically modified food, despite a scientific consensus to the contrary. This may be because people who see nature as embodying all that is good and pure are disgusted by attempts to alter it.

More troubling than skepticism about life-saving medicine and food, at least for an academic like me, is the widespread disdain among progressives for people who entertain the possibility that there are biological differences between groups, including races and sexes.

The famed Harvard psychologist Steven Pinker argues in his book The Blank Slate that while biological differences explain some of the observed differences in the behavior and outcomes of different groups, it has become taboo to openly discuss that in most academic journals and college classrooms.

Perhaps the best-known example of progressive intolerance occurred at Harvard in the 1970s, after E.O. Wilson, a well-known biologist and conservationist, published Sociobiology.

In Sociobiology, Wilson claimed that genes and cultures co-evolve, and implied that group differences would not be an especially surprising result of evolution by natural selection, given geographic isolation and limited gene flow between populations. For making that claim, as Professor Jonathan Haidt recounts in The Righteous Mind (p. 38), Wilson “was harassed and excoriated, in print and in public. He was called a fascist, which justified (for some) the charge that he was a racist, which justified (for some) the attempt to stop him from speaking in public.”

I have seen these attitudes on campus for a long time, but I recently experienced the New Creationists firsthand, through two anonymous referees who reviewed an article I submitted to an academic journal.

Like many people, I have always been struck by behavioral differences between men and women, and between different ethnic and racial groups. And like most people, I’m confident that most of these differences are due to culture, parenting, and education.

However, I have also been struck by how resistant people are in the academy to the claim that biology may play a role in explaining some of those differences—especially differences that we see across cultures, and independent of parenting style and education.

Where did this resistance to accepting claims about group differences come from?

In the first half of the twentieth century, many public intellectuals made odious claims about the moral or intellectual superiority of men over women and of some races over others. Those claims—which were often couched in pseudo-scientific jargon—helped justify colonialism, discriminatory laws, and even the Holocaust (though the primary group targeted in the Holocaust, Ashkenazi Jews, were killed because of their “domination” of the sciences, medicine, and business, not because of their intellectual inferiority).

As the twentieth century made clear, beliefs have consequences. So after the Second World War, many academics had an understandable fear of allowing themselves (or others) to believe that different groups have different average abilities or aptitudes.

Although the fear is easy to explain, and in some cases justifiable, it has led to a widely shared and religiously held dogma in academic circles: that people are, in all relevant ways, biologically identical. Those who deny this dogma should be “educated” about their implicit biases, and made to recant their views, regardless of the evidence.

After reading some recent work on the biology of group differences last summer, it occurred to me that as an ethics professor, I should write something about the moral upshot: if there are such differences, what are the consequences for how we should treat one another? Should we support policies that attempt to equalize opportunities only if they produce equal outcomes?

My conclusion was modest: if there are biological differences between groups, and if, as Lee Jussim has argued, some stereotypes turn out to be accurate in part because of correct generalizations about biological differences, these facts should not undermine our commitment to treating one another as moral equals, or to increasing opportunity for all, regardless of group membership.

But I had committed a sin in the eyes of the two referees who read and commented on my paper. I simply acknowledged the possibility of group differences while arguing that whether or not they exist, they should not matter. For having done that, the two journal referees used expletives and exclamation points to give the most venomous and dismissive feedback I have ever encountered. (Needless to say, the paper was not accepted for publication after such hostile comments.)

The New Creationists are not going away anytime soon, but there is hope that the academic world is starting to react against their attempts at thought control. For those of us who are curious enough to explore unpopular ideas, there are online resources like Heterodox Academy, where readers can find academic work that exposes bias and celebrates ideological diversity.

Let’s hope the Orthodox Academy will follow suit.