Dr. Melik: This morning for breakfast he requested something called “wheat germ, organic honey and tiger’s milk.”

Dr. Aragon: [chuckling] Oh, yes. Those are the charmed substances that some years ago were thought to contain life‐​preserving properties.

Dr. Melik: You mean there was no deep fat? No steak or cream pies or… hot fudge?

Dr. Aragon: Those were thought to be unhealthy… precisely the opposite of what we now know to be true.

Science hasn’t yet advanced as far as Woody Allen imagined in the movie Sleeper. But the Washington Post does report on its front page today, as the House Agriculture Committee holds a hearing on the government’s official Dietary Guidelines, that decades of government warnings about whole milk may have been in error.

In fact, research published in recent years indicates that the opposite might be true: millions might have been better off had they stuck with whole milk.

Scientists who tallied diet and health records for several thousand patients over ten years found, for example, that contrary to the government advice, people who consumed more milk fat had lower incidence of heart disease.

By warning people against full‐​fat dairy foods, the U.S. is “losing a huge opportunity for the prevention of disease,” said Marcia Otto, an assistant professor of epidemiology at the University of Texas, and the lead author of large studies published in 2012 and 2013, which were funded by government and academic institutions, not the industry. “What we have learned over the last decade is that certain foods that are high in fat seem to be beneficial.”

The Post’s Peter Whoriskey notes that some scientists objected early on that a thin body of research was being turned into dogma:

“The vibrant certainty of scientists claiming to be authorities on these matters is disturbing,” George V. Mann, a biochemist at Vanderbilt’s med school wrote in the New England Journal of Medicine [in 1977].

Ambitious scientists and food companies, he said, had “transformed [a] fragile hypothesis into treatment dogma.”

And not just dogma but also government pressure, official Dietary Guidelines, food labeling regulations, government support for particular lines of research, bans on whole milk in school lunches, taxes and regulations to crack down on saturated fats and then on trans fats and salt. Earlier today Walter Olson noted numerous past examples of bad government advice on nutrition.

It’s understandable that some scientific studies turn out to be wrong. Science is a process of trial and error, hypothesis and testing. Some studies are bad, some turn out to have missed complicating factors, some just point in the wrong direction. I have no criticism of scientists’ efforts to find evidence about good nutrition and to report what they (think they) have learned. My concern is that we not use government coercion to tip the scales either in research or in actual bans and mandates and Official Science. Let scientists conduct research, let other scientists examine it, let journalists report it, let doctors give us advice. But let’s keep nutrition — and much else — in the realm of persuasion, not force. First, because it’s wrong to use force against peaceful people, and second, because we might be wrong.

This last point reflects the humility that is an essential part of the libertarian worldview. As I wrote in The Libertarian Mind:

Libertarians are sometimes criticized for being too “extreme,” for having a “dogmatic” view of the role of government. In fact, their firm commitment to the full protection of individual rights and a strictly limited government reflects their fundamental humility. One reason to oppose the establishment of religion or any other morality is that we recognize the very real possibility that our own views may be wrong. Libertarians support a free market and widely dispersed property ownership because they know that the odds of a monopolist finding a great new advance for civilization are slim. Hayek stressed the crucial significance of human ignorance throughout his work. In The Constitution of Liberty, he wrote, “The case for individual freedom rests chiefly on the recognition of the inevitable ignorance of all of us concerning a great many of the factors on which the achievement of our ends and welfare depends…. Liberty is essential in order to leave room for the unforeseeable and unpredictable.” The nineteenth‐​century American libertarian Lillian Harman, rejecting state control of marriage and family, wrote in Liberty in 1895, “If I should be able to bring the entire world to live exactly as I live at present, what would that avail me in ten years, when as I hope, I shall have a broader knowledge of life, and my life therefore probably changed?” Ignorance, humility, toleration—not exactly a ringing battle cry, but an important argument for limiting the role of coercion in society.

Today’s scientific hypotheses may be wrong. Better, then, not to make them law.