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Inclusive or exclusive 'or'

Michelle H.Michelle H. Alum Member

How do we tell the difference between an inclusive 'or' (group 3 rules) or an exclusive 'or' (can be negated to mean 'and')?

Comments

  • NotMyNameNotMyName Alum Member Sage
    5320 karma

    It will generally come from the context and depend on your translating the true meaning of a given statement. Unfortunately, I'm not aware of any universal rule here.

    "I can marry Susan or Beatrice tomorrow". With the reasonable assumption that I am not a polygamist, this is an exclusive OR.

    "To score a 180 on the LSAT, you must either study very hard or be very lucky". Can a lucky person who studies very hard score a 180 on the LSAT? Sure. That makes this an inclusive OR.

    Does that help?

  • akistotleakistotle Member 🍌🍌
    9382 karma

    In the real world, if you are asked "what would you like for dessert, ice cream or cake?" I think it means you have to pick one of them, not both. (Well, you can try saying "BOTH!!" and the person who asked you would be like "okay...:neutral: ")

    In the LSAT world, I think the default reading is inclusive (unless it is explicitly stated that it's "not both"). If it says "I'm going to meet A or B", this means "I'm going to meet A or B or both" unless specifically told "but not both." I saw once in Logic Games that says "or both." (A or B or both). But this "or both" is redundant.

    But there are times that you have to interpret as exclusive. PT21.S2.Q20 (https://7sage.com/lsat_explanations/lsat-21-section-2-question-20/) says:

    A will either take a leave from her company or else she quits

    /L --> Q
    /Q -->L

    But can she do both? I don't think she can take a leave once she quits: Q --> /L; therefore it's Q <-->/L

  • JustDoItJustDoIt Alum Member
    3112 karma

    @akistotle said:
    In the LSAT world, I think the default reading is inclusive (unless it is explicitly stated that it's "not both").

    I agree with this. I think that inclusive is the way to go, but like @jkatz1488 mentioned, it really depends on the context.

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