Sufficient & Necessary Condition - About the Indicators?

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• 2 Likes

  Jonathan Wang Yearly Sage ⭐

  April 2020 edited April 2020 6874 karma

  Yes, and in fact that is precisely what you are supposed to do. Indicators are meant to activate your thought process, not substitute for it.

  Conveniently, memorizing the indicators is also made easier if you understand why each word means what it means. For example, if you understand the reason that "all" is a sufficient indicator, you ought to also never have issues remembering why "every" is a sufficient indicator as well.

  But let's be clear - even if just for efficiency purposes, you do need to memorize a good chunk of those words, enough of them that you can (1) quickly identify and understand situations where those specific words are used and (2) flexibly derive what's happening when those specific words aren't used.
• Lily2020 Member

  April 2020 edited April 2020 102 karma

  @"Jonathan Wang" - thanks so much this is good feedback.

  Now I have another question:

  It's always sunny in Philidalphia
  A.) the correct lawgic is P->S and /S->/P

  According to lawgic I wrote it incorrectly as
  B.) S->P and /P-> /S

  but thinking outside the box even if I wrote it incorrectly, when I read them both outloud they sound like they're saying the same thing?

  A - In Phil. its always Sunny & if its not sunny, I'm not in phil

  B - Its always Sunny in Phil & I'm not in phil so it's not sunny

  From a contextual point of view, if i'm reasoning through these do not A and B say the same thing and can they both lead me to understand what's occurring logically in the sentence ?

  Do you understand what I'm saying ? :$
• 1 Like

  Jonathan Wang Yearly Sage ⭐

  April 2020 6874 karma

  Would you trust a doctor who told you that he had no way to back it up, but he just 'knew' he had to remove your lung to cure your cold? If not, why should I trust you when you say you 'know' what this sentence says even though you can't prove it (and in fact, following the rules actually leads to a conflict with your interpretation)?

  Your intuition ought to be founded on sound mechanics. If the mechanics are clashing with your intuition, that means your intuition is faulty - because the rules sure as heck aren't. Words have meanings and grammar has rules. If your intuition is telling you that two statements say the same thing, but you can't prove it with the actual rules (and indeed, the actual rules are telling you that they are not actually the same), then you are doing something wrong. Full stop. And at that point, the best course of action is to figure out how it actually works, instead of ignoring it.

  Here, your English translations of P->S and S->P are the same. This is factually, objectively incorrect. This, all by itself, establishes that you do not know what the sentence says. You did guess correctly, which is nice. Can we sometimes get to the right place with an incomplete (or even completely wrong) understanding of what's going on? Sure, it happens more than you might think even with high scorers. But the real question is - are you willing to bet your score on your ability to correctly guess what they're saying, every single time, without knowing how it's supposed to work? Because by relying on your 'contextual point of view', that's exactly what you are doing.

  I want to point out that this is a case where there was very little doubt because you already 'knew' intuitively what the sentence said because none of the concepts were foreign to you and there were no grammatical or other obstacles (and also, because you already knew what the statement was supposed to say because it was given to you up front, so when you translated back from the P->S notation you could just copy the initial statement). But what about the times where you don't know? What if you just get confused by the content of the statement, or the sentence structure is complicated, or there's a tricky piece of vocabulary? Are you still willing to stake your score on what amounts to an educated guess? And even if you could magically guess correctly every single time, you'd still have absolutely no way to double check whether or not you're actually correct, so how could you ever evaluate a question confidently at that point?

  If looking at things from a 'contextual point of view' was getting you -0s in LR, then I could see an argument for not rocking the boat. But I assume you're only taking a course because that's not true, and the fact that it's not true proves that what you're proposing simply does not work. You have no way to know what a sentence says without the ability to analyze it, and you won't ever develop your ability to analyze a sentence if you don't learn how things work on a fundamental level.

  Down the road, you'll be able to just read and understand this sentence and other sentences like it without necessarily having to resort to mapping to conditional logic. But the reason for that will be because your intuition is rooted deeply in the right fundamentals - not because you skipped learning them entirely in favor of playing guessing games.
• Lily2020 Member

  April 2020 102 karma

  Thanks @"Jonathan Wang" , I really appreciate the time you took to write all that up.
  You can tell you care cuz of the amount of detail and depth that went into it - I really appreciate it ! : ) What you're saying, makes sense to me - ty so much!!
• CRISPR24 Alum Member

  April 2020 262 karma

  @Lily2020 said:
  @"Jonathan Wang" - thanks so much this is good feedback.

  Now I have another question:

  It's always sunny in Philidalphia
  A.) the correct lawgic is P->S and /S->/P

  According to lawgic I wrote it incorrectly as
  B.) S->P and /P-> /S

  but thinking outside the box even if I wrote it incorrectly, when I read them both outloud they sound like they're saying the same thing?

  A - In Phil. its always Sunny & if its not sunny, I'm not in phil

  B - Its always Sunny in Phil & I'm not in phil so it's not sunny

  From a contextual point of view, if i'm reasoning through these do not A and B say the same thing and can they both lead me to understand what's occurring logically in the sentence ?

  Do you understand what I'm saying ? :$

  Hi. I think your translation is incorrect on the second one.
  S-> P
  Shall be translated to: as long as it is sunny, it must be Philadelphia.
  This is apparently different when you say, P-> S (as long as it is Philadelphia, it must be/always sunny. Other places could be sunny too.)