I have two questions since I saw this SE answer.

First, for the following sentence:

English 'or' is only exclusive when only one premise is possible: 'You hydrate or you don't hydrate.' or 'I saw a bird or a bat [which is a non-bird].'

As a foreigner, that is different than my understanding. Say, when I am asked about my choice of the meal in a flight by "Chicken or beef?", I generally won't assume that I can have both. But having both is not logically impossible, is it?

So this is kind of different than the quoted sentence above, IMHO, "unless" the answerer means logical exclusiveness. Considering the sentence logically, I assume there is something omitted. The complete sentence may be "You can have chicken or beef (but not both, generally)".

Then, another question: in a daily scenario, what are the situations that when one says "or", he/she really means it inclusively?

When a friend asks "Do you want to have sandwich or hot dot for lunch?", I surely can offer the suggestion to have both, but I would assume my friend is presupposing that I will choose just one from the two. So, could anyone give me an example in which the "or" is inclusive, from the very beginning (the one saying it means it inclusively)?

Secondly, I don't see that the linked answer explicitly answers the question (chosen as answer though). I want to ask the same question, too; is "unless" inclusive or exclusive in daily English?

As I'm learning philosophical logics, "unless" is inclusive, but this is also different than my understanding of "unless" in daily English. When I hear "I won't talk you again unless you apologize", I generally assume that there won't be the case that I apologized and he/she still refuses to talk to me (that is logically possible, but not realistically, right?)

  • English, like most languages, does not distinguish logical OR from XOR unless required by circumstances. Mostly the context makes it obvious (like inclusive/exclusive first person plurals, another lexical feature English lacks), and pragmatic implicature, as @user6726 points out, is what determines interpretations. As for whether an apology will secure the desired result, that has nothing to do with linguistics.
    – jlawler
    Feb 27, 2021 at 20:42

1 Answer 1


Linguists generally distinguish literal entailment vs. pragmatic implicature. As for literal entailment, "A or B" mean "A or B" and if A and B both happen to be true, that's okay as well. But "Chicken or beef" literally is not a proposition and it has no truth value. However, the construction pragmatically implies "You are directed to give me one of 'chicken' or 'beef', or 'I don't want anything'". Requests don't have truth values. Some assertions like the quoted example have truth values, but even then mutual exclusivity derives from real-world knowledge and not linguistic structure.

There is always a way to make it unambiguous, but it is a mistake to say that something is omitted, because the speaker probably had no intention to give an exhaustive description of the world such that every fact is stated explicitly. Every utterance "omits" vast numbers of propositions, in fact most people have no idea how many propositions (bits of prior knowledge) their sentences depend on and they are "omitting".

On that same flight, the beverage cart offering is often preceded by a list of beverages, and the choice is generally inclusive (though that's an airline policy question). The way you can compute this is to know that they usually have lots of drinks, which they can store for the next flight, and they have a limited number of meals (usually not more than the number of passengers). In one of those buffet type restaurants, "chicken or beef?" is inclusive (as I hear), unless there is some contrary policy. In other words, it is real-world circumstances and not linguistic structure that tells you if the exclusive interpretation is implied.

There are some conventional translations between symbolic logic and English constructions, the problem being that the philosopher's version of "unless" doesn't match ordinary language use of "unless". That's the point of this q&a. "Unless you hydrate, you die" is abnormal English. "I'll pick up pizza on my way, unless you want to call from your place" is more ordinary usage. The unless clause in "Unless I'm mistaken, that book used to belong to Jim" is simply another way to say "Possibly I'm wrong but I firmly believe that...".

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.