A furor erupted a few weeks ago at Texas Tech University in Lubbock and spread across the country when a biology professor, Michael L. Dini, indicated on his Web site that he would not write letters of recommendation for medical school applicants if they could not cite evolution to explain human origins. Micah Spradling, a student in Dini’s biology class and a professed Christian, objected that citing evolution “would be denying my faith.”

The Liberty Legal Institute, a group of Christian lawyers in Plano, Texas, agreed and helped Spradling file a religious discrimination complaint with the Justice Department. Dini and Texas Tech University lawyers responded that this is about science standards, not religion, and that professors are free to choose whether and for whom to write letters of recommendation.

The stakes here are high. The road to medical school is fiercely competitive. To win admission, students need excellent grades and superlative letters of recommendation from their professors. But the issue is larger than professorial responsibilities and student rights, or whether evolution should be a litmus test for medical school recommendations.

For openers, this episode is a sad vignette of the evolution-creation wars and their political uses, fought most recently in Kansas, Ohio, Pennsylvania and West Virginia. People wedded to biblical literalism want the science curriculum to dump on Darwin, at least when it comes to human origins.

People wedded to scientific knowledge say evolution is to biology as gravity is to physics and as the periodic table of the elements is to chemistry — fundamental, proven, end of story.

The overriding issue is our respect for accumulated knowledge, no matter how uncomfortable that knowledge is or how much it clashes with preferred beliefs, religious or otherwise. After all, in modern medicine, would we still entertain a belief in the vapors over the germ theory of disease?

Would we accept a belief in the stork theory of sex over reproductive biology? Outlandish? Not really. The quickest way to make biology, biomedicine and life on Earth incomprehensible is to substitute preferred beliefs for knowledge.

The simple fact is that evolution is key to understanding disease, from new varieties of AIDS and new strains of the flu, to cancer, smallpox, anthrax, malaria, Ebola, West Nile virus, and bubonic plague. Evolution is behind the bacterial arms race — the appearance each year of new, virulent bacteria and the need for ever more powerful antibiotics. Evolution guides drug discovery, whether explored in Amazonian fungi or tested in animals along the tree of life, from mice to pigs to monkeys to chimps to humans.

Evolution bequeathed humans, other animals, plants and microbes with a common genetic code, which is critical to pinpointing the genetic causes of diseases and designing gene therapies.

The upshot is that medicine is about more than mending broken bones, worn hearts, slowed nerves, or failing minds. And astronomy is about more than spotting Mars, geology is about more than finding groundwater, and biology is about more than teaching pre-med students how cells divide.

Collectively, these disciplines reveal the history, makeup and workings of the universe, Earth and life on Earth. Each untangles the nature of things while telling us how thickly nature and humans are entangled.

Personal beliefs, such as those held by the Texas Tech student or anyone else, should accommodate that knowledge, not trash it. Our understanding of the universe, Earth and life on Earth has been hard won through 500 years of observation and experiment and is not disposable. Today we no longer teach that a deity turns the Primum Mobile to make the universe rotate around the Earth. We no longer blame a deity for causing mass extinctions of plants and animals. And we no longer think a deity spreads bubonic plague to punish sinful humans. Thank God.