Elise Amendola / AP Oprah Winfrey receives an honorary Doctor of Laws degree from Harvard University during commencement ceremonies in Cambridge, Mass., on May 30, 2013.

It’s possible to admire Oprah Winfrey and still wish that Harvard hadn’t awarded her an honorary doctor of law degree and the coveted commencement speaker spot at yesterday’s graduation. There’s no question Oprah’s achievements place her in the pantheon of American success stories. Talent, charisma, and a prodigious work ethic have rarely catapulted anyone as far as they have this former abused teenage mother from rural Mississippi who became one of the world’s most successful entertainment moguls and the first African American female billionaire.

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Honorary degrees are often bestowed to non-academic leaders in the arts, business, and politics. Harvard’s roster in recent years has included Kofi Annan, Bill Gates, Meryl Streep, and David Souter. But Oprah’s particular brand of celebrity is not a good fit for the values of a university whose motto, Veritas, means truth. Oprah’s passionate advocacy extends, unfortunately, to a hearty embrace of phony science. Critics have taken Oprah to task for years for her energetic shilling on behalf of peddlers of quack medicine. Most notoriously, Oprah’s validation of Jenny McCarthy’s discredited claim that vaccines cause autism has no doubt contributed to much harm through the foolish avoidance of vaccines.

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Famous people are entitled to a few foibles, like the rest of us, and the choice of commencement speakers often reflects a balance of institutional priorities, allegiances, and aspirations. Judging from our conversations with many students, Oprah was a widely popular choice.

But this vote of confidence in Oprah sends a troubling message at precisely the time when American universities need to do more, not less, to advance the cause of reason. As former Dean of Harvard College, Harry Lewis, pointedly noted in a blog post about his objections, “It seems very odd for Harvard to honor such a high profile popularizer of the irrational. I can’t square this in my mind, at a time when political and religious nonsense so imperil the rule of reason in this allegedly enlightened democracy and around the world.”

Many Americans are unaware that federal funding for biomedical and social science research is under siege from Congressional cuts. As a result, observers in the private sector fear a major disruption in American innovation. If we do not take seriously the ability of science to help us understand the world and drive economic growth, we risk imperiling one of the key pillars of American prosperity.

Examples of the disrespect for, and not just misunderstanding of, science are everywhere. It’s not just those who ignore climate science (alas, at our peril). Recall how Sarah Palin famously mocked research on fruit flies, ignoring the reality that most of modern genetics is built on the study of this organism, or the factually incorrect belief that women can ‘shut the whole thing down‘ when they are raped to avoid conception. It even extends to United States senators who misunderstand basic probability (thinking that a tornado could not possibly strike the same town in Oklahoma twice).

As America’s oldest and most visible university, Harvard has a special opportunity to convey its respect for science not only through its research and teaching programs but also in its public affirmation of evidence-based inquiry.

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Unfortunately, many American universities seem awfully busy protecting their brand name and not nearly busy enough protecting the pursuit of knowledge. A recent article in the Harvard Crimson noted the shocking growth of Harvard’s public relations arm in the last five years and it questioned whether a focus on risk management and avoiding controversy was really the best outward-looking face of this great institution.

As American research universities begin to resemble profit centers and entertainment complexes, it’s easy to lose sight of their primary mission: to produce and disseminate knowledge from which all of society can benefit. This mission depends on traditions of rational discourse and vigorous defense of the scientific method. Oprah Winfrey’s honorary doctorate was a step in the wrong direction.