Either

Either

This is a lightly edited version of an email that I sent to a friend on 1 December 2004.

Hi Don.

You say you are annoyed when a speaker uses the word either meaning “each”, as in “On either side of the equator the climate is tropical.”

O how I love an argument about a word! I engage in this argument in the hope of making you less annoyed. In so doing I am recklessly ignoring the lessons of history, which ought to have taught me that when I engage in argument it usually makes people more annoyed.

The word either has several uses. Let us first dismiss those uses that we are not concerned with here.

Firstly, there is an old use of either as a conjunction, meaning “or”. Thus, “Can the fig tree, my brethren, bear olive berries? either a vine, figs?” (James 3:12, King James Version.) We are not concerned here with the use of either as a conjunction.

Secondly, either can be used as an adverb in a negative clause, corresponding to also or too in a positive clause. “You can’t play the trombone? I can’t play it either.” We are not concerned here with the use of either as an adverb.

Thirdly, either can be used as a distributive, over two or more options conjoined by or. Thus, “Either he is talking, or he is pursuing, or he is in a journey, or peradventure he sleepeth.” (1 Kings 18:27, King James Version. A superb piece of sarcasm. Read the splendid story of the fire‐raising contest on Mount Carmel if you don’t know it: 1 Kings 18:20–46. I think Elijah used a flammable liquid.) We are not concerned here with the use of either as a distributive.

No: the sole use of either that concerns us here is its use as a determinative: “either hand”, “either side”.

The determinatives a, any, either, one, every are in a class of determinatives known as quantifiers. Mathematicians use just two quantifiers, corresponding to the English quantifiers one and every. This is because these two quantifiers are all that are needed in formal logic, and they are well behaved. By contrast, most quantifiers in natural English are ill‐behaved. There is a very large literature on this: Guy Carden did the definitive early studies in the 1960s and 1970s, and many others have contributed since then.

The English quantifiers a, any, either are especially ill‐mannered. Indeed, they are especially ill‐mannered in similar ways. The meanings of all three flit between “one” and “every”, just like the Borealis race that flit ere you can point their place.

Consider the quantifier a.

Consider the quantifier any.

I might have the following conversation with a learner of English as a second language:

There are 52 cards in the deck (says he); how many of them are you talking about when you say “Any card has a suit and a value”?

I am talking about one card (say I). But, as that one card may be whichever card you choose to specify, I can only say what I do say about that one card because it applies to every card separately.

Now, Don, I don’t know if you will be relieved or dismayed to learn this, but either is closely analogous:

Thus the word either, when used as a determinative in an indicative clause, means each of a pair. It always did. At school I learned “On either side the river lie/ Long fields of barley and of rye” (The Lady of Shalott, Alfred Lord Tennyson, 1842). In Revelation 22:2 we read, “On either side of the river is the tree of life,” and the words are the same whether we read from the King James Version (1611) or the New Revised Standard Version (1989).

How may sides am I talking about when I say “On either side of the equator the climate is tropical”? One side. Which side? Either side. But as that side may be whichever side you choose to specify, I can only say what I do say about that one side because it applies to each side separately.

Best wishes

Eric