If you are experiencing a feeling of foreboding today it may not be attributed to the state of affairs in the world or to the noise on the internet but rather because this is the Ides of March.

This inauspicious date harks back to high school English class and the study of Shakespeare’s “Julius Caesar,” for this was the day of the ruler’s brutal murder and a seer’s unheeded warning, "Beware the Ides of March.”

According to Shakespeare, Caesar dismissed the admonition, and upon encountering him again the morning of March 15, observed, “The Ides of March have come.” But the seer replied, “Aye, Caesar; but they have not gone.”

The end of Caesar’s reign in 44 B.C. marked a turning point in Roman history. A civil war ensued and eventually the brutal Caesar Augustus came to power, turning the republic into a dynasty. So what would have happened if Caesar had believed the warning and stayed away from Pompey’s Theater that day? We will never know.

According to the Roman calendar, the ides marked the middle of the month, either the 15th or the 13th, depending on which month. The first day of the month was called kalends, the word from which calendar is derived. It was only after the murder of Julius Caesar that March 15, the Ides of March, took on such a dark connotation.

This day is just one — and not on a par with Friday the 13th — of the many superstitious beliefs that through the ages have affected people's behavior. The late Paul Mortensen, a prominent Mormon thinker, theorized that superstitions are a survival instinct, an attempt by humans to distill the facts they gather into predictions for the future. Stephanie Pappas wrote for "NBC News" that, “When our brains can’t explain something, we make stuff up.”

Could be, but it is also true that perception can easily become reality. The Stress Management Center and Phobia Institute in North Carolina estimates that some 17 million people fear Friday the 13th.

Many of the most commonly held superstitions have some connection with religious beliefs. Crossing fingers to bring good luck may have its origins in early Christianity when one believer would cross his fingers to show support for the wish of another. Knocking on wood to assure the continuation of good fortune can be traced to the wooden cross of Christ or perhaps to the ancient belief that good spirits resided in trees.

Breaking a mirror is said to bring seven years of bad luck, possibly a connection to the belief that mirrors reflect more than an image, but a piece of the soul as well. It was once a practice to cover mirrors in the home where someone died so that the person’s soul would not be trapped inside.

And who among us has not worn a particular pair of socks or T-shirt to watch our favorite sports teams, hoping the repeated practice would assure a victory?

The vast majority of these superstitions are harmless, bringing little more than a feeling of participating in a shared experience with others following the same procedure. Few people truly believe that picking up a penny will bring them good luck, but what can it hurt? The problem comes when superstitions guide actions in opposition to established truths.

It also can be counterproductive to ignore proven facts in deference to a superstition. Passing up an opportunity, or even worse, an emergency medical procedure, on Friday the 13th could cost a person the chance at a better life, even life itself.

Superstitions can give people the sense that they are in control of results when that is not the case, when it would be advisable to concentrate on careful study and hard work to achieve a better outcome. In an age when information of all sorts is available at the click of a mouse, it can be difficult to determine what demands action, what can be verified and what should be dismissed as a falsehood. Instead, people tend to fall back on a practice that is comforting, like knocking on wood in the hope that things will turn out all right.

Superstitions in themselves are not inherently bad. Broken mirrors make a mess that must be cleaned up and it can be risky to walk under a ladder. But letting them rule a person’s life is a fool’s errand. In this age of polarization, when disparate groups hold to different “truths,” it can be tempting to discount facts that prove otherwise.

Still, it is a fact that Friday the 13th comes twice this year, in September and December. Be forewarned.

Kathy Silverberg is a former publisher of the Herald-Tribune’s southern editions. Email: kathy.silverberg@comcast.net. Twitter: @kdsilver