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When "or" means "and" does it belong to Group 3?

cardi teacardi tea Yearly Member
in General 14 karma

Hi all!

My understanding is the following:

  1. inclusive “or” gives you group 3
  2. “not both” gives you group 4.
  3. “either or but not both” gives you the bi-conditional group.

However, when "or" means "and" in a sentence, do we follow Group 3 rules? How would we write it in Lawgic?

Example: Jane is a faster eater than either Mary or Jon.

Thanks in advance!


  • Cant Get RightCant Get Right Live Member Sage 🍌 7Sage Tutor
    edited February 13 27710 karma

    Not everything should be represented conditionally, and this is a great example. To be clear, anything can be represented conditionally, so the option is always available.

    For example, let's consider famous lines from two iconic American novels, The Adventures of Huckleberry Finn and Native Son:

    HF: All right, then, I'll go to hell.
    NS: You can't make me do nothing but die!

    Or, conditionally:
    HF: If one is me, then one will go to hell.
    NS: If you can make me do something, then that thing is to die.

    Have the conditionals given us added clarity or have they just jumbled things up for no reason than just for the sake of doing it? Sure, these lines can be represented conditionally, but we should just never, never think of them this way. Sometimes, sentences are just assertions without any meaningful conditional relationships involved. An even simpler example: "They sky is blue," vs. "If the thing referenced is the sky, then the thing referenced is blue." All these are assertions, not conditionals, and so is your example.

    In your example, what is the sufficient condition? It's really just kind of an existential assertion; something like, "If the entity we're referring to is Jane . . ." We can totally do that, but it abstracts rather than clarifies the meaning because it's really just an assertion. Or, if it helps, it's a compound of two assertions:

    1. Jane is a faster eater than Mary.
    2. Jane is a faster eater than Jon.

    So we definitely treat this "or" as an "and," but that doesn't have any meaningful conditional applications here.

  • cardi teacardi tea Yearly Member
    14 karma

    Thank you so much! I really appreciate your thorough explanation.

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