The usage of either or

Question

Here are a few sentences. The first one made me confused.

1. You can have either the £15 cotton top or the £17 cotton-and-polyester blouse. You can't have both.

2. Which of these apples would you prefer? ~ I don't want either of them, thanks.

3. The sisters in the photograph were standing on either side of their dad. (OR: ...on each side..., OR: ...on both sides....)

I can understand 2nd and 3rd sentences, but the first sentence sounds more like "you can have both of them" in terms of meaning. And I can't find a general rule or formula if somebody asks me when "either" means both and when it means none of them. But when I ponder it a little further I thought maybe if I can rewrite the sentence by omitting "or" as

You can have either the £15 cotton top and the £17 cotton-and-polyester blouse.

This time could it mean "you can have both"?

Answer 1

"Either" here is being used as an exclusive-or, which means "one but not both". Technically, saying "You can't have both" is unnecessary, as that's what "either" means.

So therefore, you cannot say "either this and that" - "either" and "and" just don't work together, logically.

Answer 2

Let me try to paraphrase your sentences:

You can choose one -- the £15 top or the £17 blouse.

Which one apple do you want? I don't want this one or that one.

The sisters were standing near their Dad -- one on one side and the other on the other.

You shouldn't think of "either" as "both". You shouldn't think of "either" as "none". Instead, think of "either" as "an alternative". The sisters were standing on alternate sides of their Dad. When offered apples, you didn't want any one of the two alternatives. You can buy one of the alternative garments, but not both.

Because "either" is an alternative, it's singular.

You can have either one of these choices: the £15 top or the £17 blouse.

Which of these apples do you want? I don't want either one.

In those sentences, you're not being offered both. You're being offered a choice of one from a pair.

The last sentence is a bit more complicated. Not only did each sister make a choice, but each sister made a different choice. Each one stands on one side, but the two are not standing on the same side. If you use "on either side", then I know there are two sisters, one for each side. If you say "on both sides" then I have no idea how many sisters there are.

Answer 3

Murat asked in one of the comments:

Can I ask , does "You can have either apple" mean "you can have one apple " if there are two apples..and it doesn't makes sense if there are more than 2 apples, do it?

Similarly, he asked about the seeming contradiction in the way either is used in his first and third examples.

I think a good way of thinking about "either," to start with, is in the "either... or" sense, the way it's used in the first example. Then think of the other, seemingly different, uses as shortcuts or collapsed versions of this basic "either... or" sense.

Thus you could think of "You can have either apple" as shorthand for "You can have either this apple or that one."

Similarly, you can think of "The sisters in the photograph were standing on either side of their dad" as shorthand for "Each sister in the photograph was standing on either this side or that side of their dad" (with the implication that they both cannot be on the same side).

I would think of this kind of shorthand use of either a special, idiomatic use that is convenient and offers more concise expression in common circumstances.

Answer 4

"Either and or" are paired in the same way as "neither and nor" are paired. Either...or are used when you talk about a choice between two things. It's ambiguous when you mean "you can not have both of them". It also does not mean that you can have both of them. Instead, it means that you can have one of them; it doesn't matter which. The word "either" has been used in your first sentence as a conjunction.

The use of "either" to mean "both" is a bit limited. It's usually used with the words "side/end/hand, for example, there are trees on either side of the road, they were sitting on either side of their father, there is a toilet at the either end of the corridor, he was wearing rings on either hand, etc.

Regarding the last sentence, you can not use "either......and" to mean "both" or "one or the other". So the construction of the sentence "you can not have either the £15 cotton top and the £17 cotton-and-polyster blouse" doesn't sound correct".