Help Understanding 3.23

I struggled with sentence 3 of 3.23 until I went back and followed the example FOL translation for either/or, so I know the correct answer, but I don’t understand why that is the correct correct answer.

The sentence is: Folly belonged to either Max or Claire at 2:05 pm.

The translation was: Owned(max, folly, 2:05) ∨ Owned(claire, folly, 2:05)

Earlier the book made a point that “or” in English is sometimes an exclusive or, whereas in logic, disjunction is an inclusive or, meaning that one or both sentences are correct. In English, “Folly belonged to either Max or Claire at 2:05 pm” says to me that Folly belonged to one or the other and not both, but this remains an option in the correct FOL translation. In English-to-FOL translations, are we to assume that unless stated explicitly that both statements cannot be true, every “Either/or” is an inclusive or? Thanks in advance.

1 thought on “Help Understanding 3.23

  1. Clayton Hucks


    I was also stumped by this, but after doing a little bit of digging into the true definition of being disjunct in logic, I think we are to assume that it is inclusive. I think this is quite confusing when compared to every day English, but it is just something that we have to get used to. In summary, I think in these FOL situations, we are to assume that A can be true, B can be true, or both A and B can be true.

    I hope this helps!


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