The dangers of enthusiasm. Excavating the history of words can sometimes be as revealing as excavating the ruins of an ancient city.

Take the English word enthusiasm. Today we see this as something positive. One dictionary defines it as a feeling of energetic interest in a particular subject or activity

and an eagerness to be involved in it.

People with enthusiasm have passion, zest and excitement, and this can be contagious.

It's one of the gifts of a great teacher or leader.

People follow people of passion.

If you want to influence others,

cultivate enthusiasm. But the word did not always have a favorable connotation. Originally,

it referred to someone possessed by a spirit or demon. In 17th century England, it came to refer to extreme and revolutionary Protestant sects,

and more generally to the Puritans who fought the English Civil War. It became a synonym

for religious extremism, zealotry, and fanaticism. It was looked on as irrational, volatile and dangerous. David Hume,

the Scottish philosopher who lived from 1711 to 1776, wrote a fascinating essay on the subject.

He begins by noting that the corruption of the best things produces the worst,

and that's especially true of religion. There are, he says, two ways in which religion can go

wrong, through superstition and through enthusiasm. And they are quite different phenomena.

Superstition is driven by ignorance and fear.

We can sometimes have irrational anxieties and terrors

and we deal with them by resorting to equally irrational remedies.

Enthusiasm is the opposite.

It's the result not of fear but of overconfidence.

The enthusiast in a state of high religious rapture comes to believe that he's being inspired by God himself

and is thus empowered to disregard reason and restraint.

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