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Negating "All". Need help with negations.

ClaudiaHClaudiaH Alum Member
edited April 2014 in Logical Reasoning 9 karma
I am having a really hard time wrapping my head around Negating "All" I am in the section about "Some and Most Relationships."

If All-->Most-->Some and the negation of Some is None, then why isn't the negation of All then None?

I don't understand how we reach "Some...not..." I tried replaying the video and reading comments but it just doesn't click

Comments

  • Jonathan WangJonathan Wang Yearly Sage
    edited April 2014 6865 karma
    If I tell you that not all apples are delicious, is that the same as saying there isn't a single apple that is delicious ("none" of the apples are delicious)? How many apples are we 100% sure are not delicious when "not all" of them are?
  • ClaudiaHClaudiaH Alum Member
    9 karma
    Exactly! So let's say the case is "All apples are delicious."

    "Some apples are not delicious" is not the same as "None of the apples are delicious." Why isn't the binary cut of "all" "none?" You know, all or nothing?
  • Jonathan WangJonathan Wang Yearly Sage
    6865 karma
    Let's say the negation of 'all' was 'none'. You've now accounted for two possibilities - exactly 100% and exactly 0%. What about all the stuff in the middle? Are we just ignoring it?

    Review the lesson on negations and how they differ from opposites. You're basically taking an opposite and then asking why it's not a negation. Put simply, it's the difference between saying "none" (the opposite of all) versus "not all" (the negation of all). The answer, though unsatisfying, is very simply that the two concepts have different definitions.
  • ClaudiaHClaudiaH Alum Member
    9 karma
    I think I got confused with All-->Most-->Some but I understand now that it's not All=Most=Some. The reason that it is implied is because the "all" point 100 intersects with the range of "most" and the range of "some" but it does not include 0-99. Thank you, Jonathan!
  • hannamzhannamz Alum Member
    3 karma
    Does "Some... not" include zero?
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