Necessary Assumption Question - are we supposed to throw conditional logic negation out the window

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• akistotle Member ⭐ 🍌🍌

  March 2018 edited March 2018 9382 karma

  @"surfy surf" said:
  i.e. I will go to the store
  Negation: I will NOT go to the store.

  I don't think there is conditional element ("always") in the first sentence (I will go to the store). We don't know what it means by "I will go to the store." (Like do you sometimes go there?) So you can't really negate logically.

  The negation of "I always go to the store" is "I sometimes do not go to the store."

  @"surfy surf" said:
  If I go to the store, I will buy eggs.
  Negation: If I go to the store, I will NOT buy eggs.

  As you may have figured, this negation is incorrect.

  If I go to the store, I will buy eggs. (Store → Eggs)
  The negation is: I go to the store and I don't not buy eggs. (Store AND /Eggs) or (Store ←s→ /Eggs)

  cf. Deny the Relationship https://7sage.com/lesson/deny-the-relationship/

  @"surfy surf" said:
  JY negates the conditional statement in B.) by saying private support will become necessary. Rather than saying private support will sometimes not be unnecessary

  That's not what J.Y. says in the video. (B) states: government support → /(private sector support)

  From 3:18- of the video, J.Y. says:
  (referring to (B))"That’s also not necessary. You see, what if we negated this. Contemporary society help government maintain the fine arts AND we still need private sector support."

  He correctly negated the answer choice (B) by saying
  [government support AND private sector support] (= government support ←s→ private sector support).

  Sorry I don't think I understood what you meant by "common sense version of negation," but J.Y.'s negation in PT.33.3.16 (B) is the logical negation.
• _oshun1_ Alum Member

  March 2018 edited March 2018 3652 karma

  @akistotle said:

  @"surfy surf" said:
  i.e. I will go to the store
  Negation: I will NOT go to the store.

  I don't think there is conditional element ("always") in the first sentence (I will go to the store). We don't know what it means by "I will go to the store." (Like do you sometimes go there?) So you can't really negate logically.

  The negation of "I always go to the store" is "I sometimes do not go to the store."

  @"surfy surf" said:
  If I go to the store, I will buy eggs.
  Negation: If I go to the store, I will NOT buy eggs.

  As you may have figured, this negation is incorrect.

  If I go to the store, I will buy eggs. (Store → Eggs)
  The negation is: I go to the store and I don't not buy eggs. (Store AND /Eggs) or (Store ←s→ /Eggs)

  cf. Deny the Relationship https://7sage.com/lesson/deny-the-relationship/

  @"surfy surf" said:
  JY negates the conditional statement in B.) by saying private support will become necessary. Rather than saying private support will sometimes not be unnecessary

  That's not what J.Y. says in the video. (B) states: government support → /(private sector support)

  From 3:18- of the video, J.Y. says:
  (referring to (B))"That’s also not necessary. You see, what if we negated this. Contemporary society help government maintain the fine arts AND we still need private sector support."

  He correctly negated the answer choice (B) by saying
  [government support AND private sector support] (= government support ←s→ private sector support).

  Sorry I don't think I understood what you meant by "common sense version of negation," but J.Y.'s negation in PT.33.3.16 (B) is the logical negation.

  Oh okay thank you! Saying the negations as “some...not” in my head made it really hard for me to figure out if the AC would or wouldn’t wreck the argument. I forgot that negation means ~this & that can exist separately~. I see now that that’s what JY said in the video about government support.

  By common sense version of negation I just meant how one, before 7sage, in non-conditional logic would think of negation as just an opposite (throwing in not) “I will go to the store” negated as “I will not go to the store”

  Here at 4:56 in the video,

  https://7sage.com/lesson/birds-eat-all-day-na-question/

  PT40 S4 Q19

  JY actually scratches out “not” in the sentence in A).
  I would think the logical negation of “birds of different species do not generally....” would be “SOME birds of different species DO generally...”

  This is why I am confused if we are supposed to follow logical negation or just throw in/take out “not” from the sentence.
• akistotle Member ⭐ 🍌🍌

  March 2018 edited March 2018 9382 karma

  @"surfy surf" said:

  By common sense version of negation I just meant how one, before 7sage, in non-conditional logic would think of negation as just an opposite (throwing in not) “I will go to the store” negated as “I will not go to the store”

  I see what you mean, but I think throwing away "not" here is okay here because "I will go to the store" is a vague statement. There is no "Always" v. "Sometimes....not" relationship here. What I mean is that we don't know "I" always "go to the store."

  What does "I will go to the store" mean? Do you go there like all the time? We don't know. So it's either you will go or you won't go.

  Here at 4:56 in the video,

  https://7sage.com/lesson/birds-eat-all-day-na-question/

  PT40 S4 Q19

  JY actually scratches out “not” in the sentence in A).
  I would think the logical negation of “birds of different species do not generally....” would be “SOME birds of different species DO generally...”

  This is why I am confused if we are supposed to follow logical negation or just throw in/take out “not” from the sentence.

  I think it's okay to scratch out "not" here.

  Different birds do not generally have X.
  Negation: It's not the case that [Different birds do not generally have X.]
  　　　　　= Different birds do generally have X.

  Here, the original sentence ("Different birds do not generally have X") is so weak. It doesn't tell us a conditional relationship between birds and X. It's talking about how they don't "generally" have X.

  So I think it's similar to [Different birds -m→ /X], but we can't really translate it mechanically. The point is: the original statement doesn't fully say "Different birds always do not have X" (Different birds → /X).

  Let's look at the answer choice (B):

  The bird does not sometimes also eat Y.
  = The bird does not eat Y at all.
  = The bird always does not eat Y. (Bird → /eat Y)

  Negation: It's not the case that [The bird does not sometimes eat Y.]
  　　　　　= The bird sometimes eat Y. (Bird ←s→ eat Y)

  I am tagging @Sami, @"Cant Get Right", and @"J.Y. Ping" to see if what I'm saying is correct!
• 1 Like

  akistotle Member ⭐ 🍌🍌

  March 2018 9382 karma

  To sum up, it’s the difference between 1) and 2)

  1) J.Y. is always nice.
  Negation: J.Y. is sometimes not nice.
  (J.Y. is not always nice.)

  2) J.Y. is generally nice.
  Negation: J.Y. is not generally nice.
• _oshun1_ Alum Member

  March 2018 3652 karma

  thank you very much for clarifying @akistotle