Either Or applied to In/Out

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• 1 Like

  BlindReviewer Alum Member

  May 2019 855 karma

  I just briefly glanced over the game, and don't see a "either/or" rule, but I think you mean this?

  https://7sage.com/lesson/why-is-or-so-confusing/

  "Or" rules I always circle or pay extra attention to because we're so used to seeing "Not both" rules that "Or" rules (/A -> can feel counterintuitive.
• max_pivetta7 Member

  May 2019 edited May 2019 10 karma

  That lesson doesn't discuss the rule in application to LG as far as I can tell...

  He says at 8:55 in the video that "this is an either/or rule" and then concludes that as a result, at least one of L or M must be "in" and the other is free to float. I'm wondering why that is, and where I can find an explanation in the CC. Why is it the case that L/ > M, when in isolation from the rest of the rules, indicates that at least one must be in. Shouldn't it indicate that at least one must be out?
• 1 Like

  Beast Mode Live Member

  May 2019 edited May 2019 840 karma

  Hi

  Since it's a not both rule, at least you need one in and one must be out. You cannot have both, there is no space. Instead of writing it twice to indicate one has to be out and one has to be in, you can represent it with a biconditional indicator as you have it above and save time. This lesson will help.

  https://7sage.com/lesson/not-both-v-or-truth-tables-longer-explanation/
• 1 Like

  max_pivetta7 Member

  May 2019 10 karma

  Thanks! One more thing, if you have a second. Where might I find the lesson that explains which of the two variables to make as the "not" variable in an In/Out game, where they have a biconditional not-both relationship?

  For example, in a game where there are two committees, one of which comprises IN and one which comprises OUT, when the rule is "U serves on a different committee from that on which G serves."
  ^How would I know which of the two biconditional variables to make as the not-included one? Would it be U <---->/G or would it be /U <----> G ? Which core curriculum lesson explains the approach to this?
• Beast Mode Live Member

  May 2019 edited May 2019 840 karma

  You can find the lesson here https://7sage.com/lesson/two-types-of-biconditionals/. In your example, "U serves on a different committee from that on which G serves." This is the always apart, never together biconditional because the rule states U and G have to be on different teams. It doesn't matter which one we cross out because in our biconditional chain they both indicate the same idea that they have to be always apart. When we unchain the biconditional, U <---->/G, we get U ---->/G and it's contrapositive G ---->/U. From this we can say that when U is in, G is out. Also, when G is in, U is out.

  Now let's split this /U <----> G, we get /U ----> G and it's contrapositive /G ----> U. From this we can say that when U is out, G is in. When G is out, U is in. You see how we are really saying the same thing and it doesn't matter which one we cross out as long as we know that they are always apart and never together. Both of our chains indicate the same thing. The biconditional chain saves us time when we do games so that we don't have to write out the rules when we can just represent them in one chain. I hope this helps.