Conservative professors are vastly outnumbered on college campuses by those on the left. And conventional wisdom holds that the source of the imbalance is flagrant ideological bias on the part of the faculty members and administrators who make hiring decisions.

The first claim is mostly (though not entirely) true. But the second is almost entirely wrong.

The consequences of that error are significant and alarming, encouraging a view of universities that is undoubtedly contributing to the recent sharp uptick in hostility toward higher education among Republicans. The reality of academic life is more complicated — and less deserving of a destructive, indignant response.

The ideological imbalance on campus is real, but it isn't as all-pervasive as rhetoric on the right tends to presume. Professional schools — business and medical schools especially — show no leftward bias and sometimes even lean to the right. Hard scientists may be far more predisposed toward atheism than the general public, but their work has nothing at all to do with politics as typically defined. The social sciences lean more heavily toward the left, though economics departments often employ significant numbers of libertarians, while political science departments frequently include more than a handful of conservatives.

That leaves the humanities — English, comparative literature, philosophy, history, and various interdisciplinary departments of cultural studies — as the place on campus where the ideological imbalance is usually most evident.

Is this because faculty members in the humanities are politically engaged leftists who actively avoid hiring conservatives? There may be some of this. But more significant is the fact that many conservatives are led to study the humanities for reasons that differ dramatically from the motives that typically prevail among faculty members and receive the richest professional rewards within the academy. This is especially true at the most elite universities, where a strong record of research and publication in peer-reviewed journals and university-press books is a requirement for hiring, tenure, and promotion — and where the ideological imbalance is most pronounced.

Professors are trained as graduate students to become scholars — and scholarship in our time is defined as an effort to make progress in knowledge. The meaning of progress in the hard sciences is fairly obvious. But what does it mean to make progress in our knowledge of, say, English literature? One possibility is to find obscure, previously neglected authors and make a case for their importance. (This could be described as making progress in knowledge by way of expanding the canon.)

Another possibility is to bring new questions to bear on old, classic texts. But where will those new questions come from if not the concerns of the present? This is how professors end up publishing reams of studies (and teaching gobs of courses) on such topics as "Class in Shakespeare," "Race in Shakespeare," "Gender in Shakespeare," "Transgender in Shakespeare," "Intersectionality in Shakespeare," and so forth. To tease out those themes in texts that have been read, studied, and debated for centuries certainly constitutes progress in knowledge, since those who publish the research have said something genuinely new about something old and familiar.

One reason why conservative scholars tend not to conduct this kind of research is that they're not especially interested in questions of class, race, gender, and related issues. But that's not because they'd prefer to achieve progress in knowledge by bringing a different, more politically conservative set of questions to bear on classic texts. ("Supply-Side Economics in Shakespeare"? "Hawkish Foreign Policy in Shakespeare"?) Rather, conservatives are usually drawn to the study of the humanities with a very different goal in mind — nothing less than pursuit of the timeless human wisdom they believe can be found in the great books of the past. What kind of research and teaching does this motivation produce? Studies of, and classes in, such topics as "Love in Shakespeare," "Friendship in Shakespeare," "Justice in Shakespeare," "Death in Shakespeare," and "God in Shakespeare."

These are classical subjects that centuries of people have written and thought about while reading the great playwright and poet. What's new to say about them? Probably nothing. Instead, reflecting on such themes entails a rediscovery of knowledge that past readers may have possessed but that must be reacquired by every reader, by every student, anew.

By definition, that's not "progress in knowledge," since it denies that a contemporary scholar necessarily knows more on the subject than a reader from a previous century. It presumes that the only form of "progress" is each individual’s advancement in coming to understand the perennial problems and puzzles of the human condition, and it looks to great writers of the past for help in acquiring that understanding.

This explains the resistance shown by many conservatives toward efforts to achieve progress in knowledge by expanding the canon: They tend to presume that the authors and books that come down to us as "great" will provide more guidance than those that have disappeared into obscurity. It also explains why many conservative academics prefer to teach at small liberal arts colleges, where they can spend their days poring over the same old books by the same old writers, making their own personal progress toward understanding, in part by leading new generations of young people to begin their own personal progress toward the same goal.

But this means that the culture of the research university stands in considerable tension with what motivates many conservatives to pursue academic study in the first place. Is this an ideological conflict? At a deep level, perhaps, since the ideal of pursuing research that contributes to progress in knowledge was first proposed by philosophers in the early modern period for profoundly political reasons — in order to encourage the development of a culture of scientific and technological discovery that would eventually overthrow the rule of priests and other entrenched authorities. This was an ideal forged in the Enlightenment. And the modern research university is one of the greatest legacies of the Enlightenment.

As with progress, conservatives tend to view "enlightenment" differently — less as an ongoing species-wide striving for ever-greater illumination and more as an individual pursuit that begins from scratch with every person who begins to ponder, with the help and guidance of select teachers, the perennial mysteries and wonders of human life and experience.

That difference is the real, or at least the deepest, reason why conservatives are so rarely found in the humanities departments of our leading research universities. And it has nothing much to do with partisan politics.