Dr. Edmund Kern is an Associate Professor of History at Lawrence University in Appleton, Wisconsin, specializing in European religious culture and witchcraft trials. He is currently finishing a book on the witch trials of Styria, 1546-1746, and is working on a book about morality in the "Harry Potter" series. He spoke with Beliefnet producer Wendy Schuman on the intersection of superstition and religion.

Are superstitions found in every culture?

I do think that superstitions are a universal or a near-universal phenomenon. However, ultimately superstition is in the eye of the beholder. In some cultures around the world we find practices we would label superstitious, but those practices would not be understood as such in those cultures. The notion of superstition is dependent on certain understandings of rationality.

So if you make a certain gesture to make something happen, you don't call it superstition--you call it religion?

Yes, or something else-ritual. Superstitions are in a sense all ritual activities.

Have you come across any common characteristics of superstitions?

There are five categories or types of superstitions that I've come up with. You might find other historians or folklorists dividing things differently.

The most common [form] is ritualized custom or habit. For example, people who throw a pinch of salt over their left shoulder when they spill salt are probably doing that because of their upbringing rather than any conscious decision on their part. They became familiar with it because their parents did it, or their grandparents, so they formed habitual actions that are in origin superstitious even if they don't perceive them that way.

Another quite common form is the observance of taboos or omens, a whole host of do's and don't's which have to be followed, or a series of signs that might portend something of importance.

Can you give an example of that kind of taboo?

One that comes to mind is that grooms are not supposed to see their brides before the wedding ceremony on the day of the wedding. Many people go to great lengths to see that doesn't happen, even though they might otherwise be perfectly rational people.

What about omens-a black cat crossing your path, for instance?

Yes, that would be an ill omen. Another example of these kinds of omens are crows. Some people [Native American groups] believe that when one sees crows during the day, depending on what kind of activity the crows are engaged in, that can be an indicator of how one's day will go. So if the crows are on the ground digging for food, that will be an indication that the day will be concerned with details, getting things done. If on the other hand the crows are soaring or in flight, that would be an indication that the day will somehow transcend the normal, the everyday, and perhaps be a good day for initiating new endeavors.

In Europe, though, crows and ravens are usually birds of ill omen. So this Native American belief is a little more interesting, a little more nuanced.

Another form that superstitions can take is the observance of sympathetic powers, the idea that certain times or certain objects or certain elements found within nature have with in them a kind of power. And if you use the object or observe the times, you can take advantage of that power inherent in the object.

Is that the kind of ritual Tom and Huck were engaged in? When the moon was full they were swinging a dead cat around...

Yes, exactly. By the way, I think the concept of sympathetic powers is one of the explanations for why people are so superstitious around cats. I think that cats remind us of our own humanity and our own animality. We recognize the intelligence of a predator and that reminds us of ourselves and our origins in the animal world. Cats can at times appear very human, they can sound human and their actions are in some respects very human as well, their curiosity, the ability to solve problems.

It becomes complicated, though, when you try to search out the origins of superstitions. I think what we can do at best is speculate in an informed fashion about the origins, you can never really say with any degree of certainty how a superstition emerged. What we can do is look into the past and find early examples from the first or second century. That doesn't mean that the practice began then-it might have begun much earlier, but we have no record of it.

Is knocking on wood a way of appealing to sympathetic powers?

I think the best explanation for that is to be found in the pagan beliefs of ancient Europeans, where many groups believed that objects in nature possessed animistic powers. In other words, that there was a kind of spiritual power inherent in every object. The famous example, of course, is the veneration of trees by the Druids, or the recognition that there were sacred groves.

I think touching wood might be a legacy of that. One would call upon the power of wood to forestall bad luck.