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I want to say that it's possible that at least one of {A,B} is true, and possibly both of them are true. Is it correct to phrase it as "either A, or B, or both are true".

tchrist
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guest
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  • [on hold] the question is a dupe of http://english.stackexchange.com/questions/13889/does-either-a-or-b-preclude-both-a-and-b –  Sep 20 '13 at 22:47
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    I don't agree - I think it's covered rather in the 'Either vs. among' thread at http://english.stackexchange.com/questions/59148/either-vs-among (where tchrist and FumbleFingers point out that 'either' may be used when there are more than two alternatives). – Edwin Ashworth Sep 20 '13 at 23:11
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    Either or both of A and B are true. – tchrist Sep 21 '13 at 01:05
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    I think this is perfectly acceptable, and less confusing than some of the alternatives proposed. – Kaiser Octavius Sep 21 '13 at 01:47

5 Answers5

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Mathematical logic speaks of an exclusive-OR and an inclusive-OR. Typically parents offer exclusive-OR choices to their children. ("You can have either cake or ice cream"; "...but not both" is implied.) You can say "Either a or b, but not both" to clarify an exclusive-OR, or "Either a or b, or both" to clarify an inclusive-OR. The "but not both" or "or both" in a sense wraps around the whole "either a or b" part.

Joe Meyers
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Typically you would list them in order with commas and leave off "or" until the last item, as in:

"either A, B or both are true"

Keep in mind that there are those who prefer a comma after B as well:

"either A, B, or both are true"

Cyberherbalist
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    Either is typically reserved for two options. Some people will object to using it for three, as in your examples. (Whether or not they have a point, is a separate issue, it's just something to be aware of.) – RegDwigнt Sep 22 '13 at 12:44
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Since "or" is neither logically or commonly exclusive, "A or B" expresses exactly what you're aiming for. If you're getting into troubles about clarity I would suggest rephrasing the particular sentence in a way that leaves no doubt:

Maybe I will open the door to my right or my left

could translate to

I might open any of those doors

npst
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Usually just "A or B" implies what you want, but if you want to clarify that meaning is not exclusive, you can use and/or.

LudwigNagasena
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The multiple form would be: 'Any or all of A and B are true.'

Yawar
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