Student Stumper 53: “Whether” vs. “Either”

QUESTION: Are “whether” and “either” interchangeable?

ANSWER: No. That’s the simple answer, and I was quick to state that in response to this recent question, but what took me by surprise was the confusion itself. I’m aware that students will ask about “whether” vs. “if.” I also know that lack of parallel structure creeps into sentences with “whether.” But I’d never thought about any overlap between “whether” and “either.” What’s the source of the confusion? I’ve since given this some thought.

Both words can imply as set of possibilities:
1a. Whether it’s sunny or rainy, the marathon will take place.
2a. You can either watch or participate in the big event.

With a bit of creativity, you can reword those sentences to accommodate either word:
(And yes! I just used “either” again. Why? I’ll get back to that.)
1b. It will either be sunny or rainy, but the marathon will still take place.
2b. Whether you watch or participate, the marathon is a big event.
Examples 1a and 1b are close in meaning. Examples 2a and 2b are related, but less of a match.

As seen in example 1a, whether can imply something will happen no matter what: it doesn’t matter if it’s sunny or rainy because the marathon will take place regardless. Either doesn’t have this meaning unless we explain the inevitability with other words.

Either…or refers to a choice, usually between two items. However, I hear and see use of three or more options:
3. You can either train alone or with others. The choice is yours.
4. When I run the marathon, I’ll wear either my favorite shirt, my lucky running shirt, or the shirt the organizers gave me.
By the way, Merriam-Webster’s Learner’s Dictionary was one source that listed an example with either followed by more than two items.

What guidelines can help learners avoid confusion?
– Whether is like if when we report questions:
5. They asked me whether I would participate. = They asked me if I would participate.
Similarly, embedded questions/wh-clauses formed with if may also use whether, which generally sounds more formal:
6a. We don’t know if Kim will run the marathon this year.
6b. We do not know whether Kim will run the marathon this year.

– Whether often implies a choice of doing or not doing something and “or not” may be understood without being stated:
7a. They asked me whether or not I would participate.
7b. We do not know whether or not Kim will run the marathon this year.
Grammatically, whether can easily pair with an infinitive to express a choice or uncertainty about one’s choice. This structure implies should:
7c. I have to decide whether to participate or not. = I have to decide if I should participate or not.

– Either…or always states at least two clear options.
8. You can either run or walk. You get to choose.

– Both words can function as conjunctions, but either is also an adjective. Remember my earlier example?
9. You can reword those sentences to accommodate either word.
Whether cannot substitute in that sentence. It also cannot function like a pronoun or adverb, though either can:
10a. You can run along Lake Avenue or Elm Street. Either will give you practice running up and down hills.
10b. Larry didn’t finish the marathon. Kate didn’t either.

Got tips to help learners avoid confusion with whether and either? Please share them.

Image by Gerd Altmann from Pixabay