I have posed a similar question to the forum and received this brilliant summary. I hope you will hang on to it as I have:
How "either" and "neither" are used.
"either" means, “one or the other of two”.
"neither" means, "not one or the other of two".
"either" and "neither" are are called correlative conjunctions; they work in sets:
either . . . or . . .
neither . . . nor . . .
They are also singular in number, so they take a singular verb. For example,
Either Sam or Max has the best grade in the class. (singular verb)
Neither Sam nor Max has the best grade in the class. (singular verb)
But there's an acceptable exception. If there's an "of" phrase with a plural noun (e.g., 'of the candidates'), some speakers might choose a plural verb. The reason being, 'candidates', a plural noun, is closer to the verb than is singular 'Neither'.
Neither of the two candidates are running next year. (plural verb)
Neither of the two candidates is running next year. (singular verb)
It'd be best to reword the sentence, like this,
Neither candidate is running next year.
None of the three candidates is running this year.
"none" refers to three or more, whereas "neither" and "either" refer only to two.
If the subjects do not agree in number, like,
Neither you nor I _____ going.
the rule is to use a verb that agrees in number with the closest or nearest subject, like this,
Neither you nor I am going.
Neither I or you are going.
Hope that helps.
- For Teachers