# Either and vs. Either or

(1) In this question on math.SE a question about the meaning of 'either' before a list which ends with 'and'. The meaning of

``````either a, b, c, or d
``````

is from this answer sort of clear in that it means a or b or c or d. Even if or can mean all included, the either seems to indicate an exclusivity. so exactly one of them. But what does

``````either a, b, c, and d
``````

mean? Is this even current English?

(2) in the same question there is the question about what

``````any one of a, b, c, and d
``````

means. So I would also like to know what

``````any one of a, b, c, or d
``````

means?

• Why the downvote? Jun 6, 2012 at 0:29

Yes, you're right that the correlative conjunction either ... or ... is simply a summation of successive or's -- either ... or ... or ... or ..., with only the last or obligatory. Same thing without either, except that then it's not clear that this is disjunction with or, instead of conjunction with and (which is more common, and unmarked). But if you start the list with either you don't need to include and stress or all the time.

Either ... and ..., on the other hand, is simply wrong, and probably just a typo if written.

The answer to the second question is that

• any one of a, b, c, and d is mathspeak for any (or some) member of the set [a, b, c, d]

while

• any one of a, b, c, or d is not mathspeak, but simple enumeration, with "free-choice" any.
• What do you mean by "free-choice" any? Jun 5, 2012 at 19:39
• There are at least two different uses of any in English. By far the more common is Negative Polarity any; but a different sense implies one may take a choice of some member of a set. NPI any requires a Negative environment, so it's rarely a subject, but free choice any is often a subject, e.g, "Anybody can learn English in just 10 weeks!" which asserts that a person picked at random can do this, which in turn implies that everyone can do this. Including oneself, one is sposta conclude. Jun 5, 2012 at 20:08
• I wouldn't read any one of to include or some of, regardless of conjunction; I would take the one to mean you have to pick just one. Any of, on the other hand, I would assume included the possibility of more than one, up to all. I'm not a mathematician, though. Oct 7, 2016 at 12:28

Your understanding of "either a, b, c or d" is correct. But with either, we never use and. Hence "either a, b, c and d" is incorrect.

"any one of a, b, c or d" means one among a, b, c, and d.

"any one of a, b, c and d" seems vague.

I'm a mathematician, and I'd just like to confirm that, although some of us have a reputation for mangling the English language, I've never encountered the "either ... and ..." mangling before. I'm inclined to assume it's just a typo.

either a, b, c, and d

This means that possible combinations include ad, bd, and cd.

either a, b, c, or d
any one of a, b, c, or d

Both of these mean that the possibilities are limited to a, b, c, or d.

• Yes, that was how I initially had read it. I was figuring that the commas were instead of or, so we get one of a, b, c in combination (and) with d. Jun 5, 2012 at 19:45
• If it truly means what you say, then I would suggest repunctuating: either a, b, or c; and d
– J.R.
Jun 5, 2012 at 20:30