Professor Richard Borcherds of Cambridge University has just been awarded [August 1998] the Fields Medal, the mathematicians’ equivalent of a Nobel Prize, for proving a highly abstruse result in number theory called the moonshine conjecture.
It seems it was given this name because it was based on a coincidence between a result in number theory and the number of symmetries in an exotic concept called the Monster object. It was thought so unlikely that two such distinct areas of mathematics should have anything in common that the conjecture was described as moonshine, and the name has stuck.
Professor Borcherds was quoted as saying, “I was over the moon when I proved the moonshine conjecture”, a nice conflation of two of the common evocations of the Moon in the language.
Moonshine originally meant the same as moonlight. In A Midsummer Night’s Dream, Snug asks whether the moon will shine the night they perform their play, and Bottom replies in a brief panic: “A calendar, a calendar! Look in the almanack; find out moonshine, find out moonshine!” It still has this literal meaning in poetical or elevated contexts but we no longer use it in that way in daily life, unlike the matching sunshine. Instead, it commonly means something insubstantial or unreal, and so foolish or visionary.
Offhand, I can’t think of another scientific theory which has such a disparaging public name, though quite a number have been called rude things in private. But compounds containing moon are often pejorative. Almost by definition, it seems, anything done at night is going to be illegal or immoral, or both, whether by the light of the silvery moon or in its absence.
The word for working at a second job, usually at night, moonlighting, is actually a modern re-use of an older term describing some nocturnal expedition or illicit action. And there is a wonderful British expression, now somewhat long in the tooth but still understood: a moonlight flit. A person who does one of these decamps or moves house under cover of darkness to avoid a debt, usually paying the landlord his rent.
Another such expression, long defunct, is moon-curser or mooncusser. This was originally a link-boy, a person who carried a torch of flaming pitch to guide pedestrians at night before towns had street lights. (Link here is probably an old word for the cotton tow that formed the wick of the light.) The moon-curser pretended to guide people to their destinations but actually led them into the hands of robbers. Moonlight was no good to such rogues, for then the link-boy wasn’t needed to help people find their way about. Later, the same word was applied to wreckers in England and on the eastern seaboard of America, particularly around Cape Cod, who were accused not only of salvaging what was washed up on shore from genuine accidents, but of bringing disaster about by shining lanterns from the shore to confuse seafarers. Moonlit nights were a hindrance to the latter activity.
At one time Wiltshire people were thought excessively slow and stupid and a story was told in neighbouring counties to illustrate this. A group of local yokels were found raking a pond at night. When asked what they were doing, one explained that they had seen this big white cheese in the pond and were trying to get it out. The word moonraker was for long applied generally as a term for a simpleton. Even today, by that tendency people have of taking ancient insults to their hearts, some people from Wiltshire use it to describe themselves. But as you might expect they have a different explanation of the story. The moonrakers were indeed found in the pond, but by Excisemen. They pretended to be drunk and told the story to divert attention from their real intention of combing the pond to retrieve the barrels of smuggled brandy they had hidden there.
Which brings us back to moonshine again, this time in the sense of illicitly made alcoholic drink. It’s commonly said that such liquor is so called because it was distilled at night to evade the attention of the Revenue. But in its first sense in England it referred to spirits that were smuggled at night across the Channel from France, and also to such contraband that was transported inland, again by night. So the Wiltshire moonrakers were indeed searching for moonshine, but in a different sense. The word died out in Britain but remained common in North America with the slightly different meaning that was later re-imported into British English.
Over the moon is at least as old as any of these. It was probably already a common expression of pleasure when the nursery rhyme containing the line about the cow jumping over the moon was first recorded in 1765. It became notorious in the seventies in Britain through its over-use by television football commentators, to the extent that it aroused mirthful comment and parody (another expression, sick as a parrot, describing one’s feelings of dismay at some unfortunate outcome, is now equally strongly associated with British football).
So the moonshine conjecture is in good linguistic company, even though, having now been proved, it is no longer moonshine. I hope nobody tries to rename it.