Subjunctivitis

   One of the least understood verb forms in English is the subjunctive. But despite the widespread lack of understanding, the reality is that we use it often, even as we can't explain how it works.
   In a way, it's like driving a car or operating a computer. Many of us do both without the least understanding of what goes on under the hood or behind the screen.
   Put simply, there are only three of what grammarians call moods in the English language: Indicative, imperative and subjunctive. Loosely translated from the Latin labels they were given centuries ago, they mean: Show me, tell me, and maybe. More specifically, "indicative" comes from the same root as "indicate," or "point to," and is used for verbs indicating what is. "Imperative" is related to "imperious" and "imperial," and is used to command someone to do or say something. Finally, the subjunctive. The roots of the term tell us that the mood is somehow "sub-joined" to something else, often through an "if" phrase. That is, its existence depends on something or someone else.
   Shakespeare was a master of the form. Consider this famous line, from Julius Caesar: "An it be so, it were a grievous fault." (The word "an" is only a very early form of "if.")
   Or this, from an old Irish adage:

If if's and an's were pots and pans
We'd have no use for tinkers.

   The thing about studying grammar in elementary school and high school is that it gives you names for things you already know. And by giving these things Latin-based labels, teachers impart more prestige to themselves and to the subject.
   The medical and legal professions do the same thing. Ask a doctor for the name of the indentation, or pit, in front of the elbow, and he will tell you it's the "ante-cubital fossa." Which is Latin for "pit in front of the elbow."
   But I digress. Be not afraid of the subjunctive. (That sentence is an imperative.) It is a useful mood. (That's indicative.) If this were not so, the mood would have disappeared long since. (Subjunctive -- one condition depends on another.)