# either or both A and B vs. either or both A or B

When using the phrase "either or both", should we use "and" or "or" for the items coming thereafter? or maybe "and/or"?

Example:

It must have something to do with either or both external environment and/or internal character.

I consider that “either or both” should be followed by “of”. That leads to “and” separating the items in the list on the basis that “or” yields a single item rather than both of them. So

It must have something to do with either or both of external environment and internal character.

• If both A and B are true then A or B is also true Elementary Logic (see bottom). Your statement that "or" yields a single item is suspect. You are encouraged to provide evidence to support your answer. See How do I write a good answer?. – MikeJRamsey56 Jul 6 '17 at 22:43
• "A or B, or both" seems more idiomatic (if OR is exclusive) than "either of both of A and B": "It must have something to do with (either) external environment or internal character, or both." – curious-proofreader Jul 7 '17 at 1:09
• Adding of to that sentence doesn't sound quite right to me. I might be missing something here, but I think you'd add of to the phrase 'either or both' if and only if you add it to the word 'either' (or perhaps the word 'both') on its own. Can you cite any sources or authoritative examples that support your assertion? – Lawrence Jul 7 '17 at 4:41
• @MikeJRamsey56 “or” is not being used as a logical operator in this context. “Apple or orange” means one piece of fruit. I do take your point that I ought to have provided evidence. I am a newbie on this forum. – Pete Forman Jul 7 '17 at 10:51
• @PeteForman I was a semester away from a dual major in Mathematics; it forces its way out sometimes (sorry). – MikeJRamsey56 Jul 7 '17 at 14:45

Conventionally, the sentence should make sense by either using only the left hand side of the slash throughout the sentence, or by only using the right hand side. Thereby, this is how it should be written:

It must have something to do with either/both external environment or/and internal character.

The above sentence could be broken down to two, the left hand side of the slash using either and or:

It must have something to do with either/both external environment or/and internal character.

or the right hand side of the slash using both and and:

It must have something to do with either/both external environment or/and internal character.

The slash or virgule can be translated as or according to thepunctuationguide:

The slash sometimes serves as shorthand for or

• The question is about the sentences starting with "either or both" – Sasan Jul 7 '17 at 15:40
• Why go to the complication of having two slashed expressions when the relatively conventional "and/or" would express the same thing with only one slash? – herisson Jul 7 '17 at 17:37
• @Sasan if you want to start the sentence wtih "Either or both...." you could try this Either or both external environment and internal character.must have something to do with it If this what you're after,let me know and allow me to edit my answer! – 3kstc Jul 10 '17 at 3:40
• So, between the items coming after either or both we should use and? – Sasan Jul 10 '17 at 8:05
• @Sasan Yes, you should use and if you're using either or both. – 3kstc Jul 10 '17 at 8:07

It must have something to do with both external environment and internal character.

It must have something to do with either external environment or internal character.

Ultimately, it must have something to with something. Neither both nor either/or is needed in this semantical context of uncertainty.

• The question is about the sentences starting with "either or both". – Sasan Jul 7 '17 at 15:40
• Since "or" includes "and" the second sentence is true when it is both. Therefore the second sentence is true for "either or both". The first sentence is true only when both are true. What is true for math is true for English. Don't confuse "or" with "exclusive or", or if you prefer, with "either A or B". – MikeJRamsey56 Jul 7 '17 at 16:56
• Yes! Math and english are the same maybe for Siri. – user230919 Jul 7 '17 at 17:54