Ideology is a double-edged sword. Dedication to a set of beliefs can be admirable, but when it leads to inflexibility and obstinance in the face of overwhelming evidence to the contrary, it is a dangerous thing. Such ideological rigidity -- often found among the adherents of various philosophical, religious, and political doctrines -- can lead to the rejection of evidence-based inquiry, which serves as the bedrock of modern science.

Recently, we published an article on how postmodernism, a philosophical movement that embraces relativism and views reason with suspicion, is completely at odds with a scientific worldview. Now, in an excellent essay for Quillette, former feminist Toni Airaksinen warns about the dangers of modern feminism, particularly as taught in women's studies classes, which she has described as a "rabbit hole" that leads to a "perverse wonderland where up is down."

Ms. Airaksinen's concern is that feminism has been built upon ideas that can neither be proven nor refuted, precisely the sort of evidence-free groupthink that typifies unscientific thinking. Her criticism is blistering. She describes an ideology where supporting facts are few and "knowledge itself is considered a patriarchal construct." No wonder postmodernists often find common cause with feminists.

It shouldn't come as a surprise, therefore, that feminists have butted heads with biologists. Social construction, a pillar of modern feminism, posits that characteristics such as gender are determined by culture rather than biology. As Simone de Beauvoir famously said, "One is not born, but rather becomes, a woman." Ms. Airaksinen describes just how far modern feminism takes this belief:

[M]erely mentioning biological differences can be wrongthink. Or worse, as I learned in one of my classes, it can be upsetting to genderqueer or transgender students. Thus, some of the root causes of what makes men and women differ — hormonal, neurological, and biological differences — is left out of the discussion.

Obviously, culture does play a large part in shaping behavioral differences between the genders. But to deny the prominent role of biology in our lives is dangerous nonsense. Ignoring it will not empower women but endanger them. Multiple sclerosis, lupus, migraine headaches, chronic fatigue syndrome (myalgic encephalomyelitis), depression and anxiety, and irritable bowel syndrome are more common in women. Will ascribing these pathological differences to patriarchal social constructs help find a cure?

Unfortunately, feminist ideology has already undermined academic freedom. Despite such well documented biological and psychological differences between men and women, some scientists have admitted being afraid to talk about them out of fear of being labeled "sexist."

Few in a modern, liberal society would doubt the historical benefit of feminism. For a society to be prosperous and just, respectful treatment and equality of opportunity must be extended to all. But modern feminism has advanced well beyond its laudable origins to encapsulate an ideology that is increasingly detached from reality. As Ms. Airaksinen eloquently concludes, "[T]he thick academic prose of feminist scholars confers gravitas to what otherwise could resemble political propaganda."

That empowers nobody.