141 comments

  • Edited Friday, Nov 28

    All cats (subset) are mammals (superset). So, mammal club's membership is necessary to be in the cat club.

    But not all mammals are cats. So, cat club membership is sufficient, but not necessary, to be in the mammal club.

    A cat must be a mammal. But a mammal may or may not be a cat.

    1
  • Edited Tuesday, Nov 25

    Subset → Superset Being in the small group is enough to be in the big group .If you work at OPA, you definitely work in D.C. politics

    If you work at OPA, then you definitely work in D.C. politics — being in the small group is sufficient for being in the big group.

    BUT…

    You can work in D.C. politics without being in OPA (e.g., Cyrus, Mellie, Fitz when he was president).

    So being in OPA is not necessary to be in the D.C. politics group.

    Superset → Subset Being in the big group is required but not enough to be in the small group Olivia trusting you doesn’t automatically place you in OPA

    To be in Olivia’s inner circle, you MUST be someone she trusts. So being in the big group (people she trusts) is necessary.

    BUT…

    Just because she trusts you doesn’t automatically put you in her inner circle. For example, she trusted Fitz, but he wasn’t in OPA’s inner circle.

    So being in the big group is not sufficient to put you in the small group.

    If you got this far, may God supply you with whatever you need to do well for this test!

    1
  • Friday, Nov 21

    so would an example be Birmingham (subset) and Alabama (superset). Birmingham is sufficient for living in Alabama, but not necessary. Living in Alabama is necessary to live in Birmingham.

    4
  • Tuesday, Nov 04

    Loved the way he explained this. Subset (NYC) membership is sufficient (Okay) for superset (USA) membership because you have to be in the USA to be NYC but it is not necessary because you can be the Grand Canyon and still be in the USA.

    While

    Superset (USA) membership is necessary (needed) for subset (NYC) membership because you have to be in the USA but not sufficient if its earth.

    4
  • Tuesday, Oct 21

    google helped me on this one. i was getting too caught up in the language.

    6
  • Sunday, Oct 05

    He explained it well— but I got confused a bit so I added more understanding.

    A mammal subset is not dependent on cats— it’s Sufficient (S) as a stand alone. Whereas, Cats are dependent as a Necessary (N) needing mammals in order to stand.

    A cat (subset) — is a (necessary) — mammal (superset).

    A mammal (superset) — is Not (why? Bc, Sufficient) — a cat.

    And we know this— because mammals are a larger extended category compared to cats— where as the only difference within cats are modifier (fat, colored, etc).

    Hope this helped. This is from my notes.

    10
  • Wednesday, Oct 01

    can someone explain Superset membership is necessary for subset membership, but not sufficient. in terms of the cats?

    0
  • Tuesday, Sep 30

    I had a hard time understanding this, but I continued through the lesson. Once you work with some real LSAT problems, come back to this video. It will click!!!

    2
  • Edited Thursday, Sep 25

    I understand the logic, I just don't understand the WORDS (sufficient & necessary)

    1
  • Saturday, Sep 13

    So say I'm Lubbock, Texas.

    To be in Lubbock it is necessary that I am in Texas. To be in Texas it is necessary that I am in the USA.

    Lubbock is a subset of Texas and USA is a superset to Texas.

    It is sufficient if I live in Texas to be in Lubbock and sufficient to be in the USA if im in Texas?

    0
  • Edited Saturday, Sep 06

    I think I understand it but I’m not sure …

    It is sufficient that basketball is a sport, but not necessary for the sport to be basketball????

    2
  • Thursday, Sep 04

    A tip to help anyone that is confused: Don't use the words "membership", "Sufficient", and "necessary." Instead just say something like this: Being a part of mammal set is not enough to be a part of cat set—but being a mama is needed to be a part of cat set. Or: You need to be a mammal or a part of mammal set to be in the cat club. Play around with the words.

    0
  • Wednesday, Sep 03

    subset membership--->superset membership, in NYC--->in USA

    0
  • Sunday, Aug 24

    ya'll get any of that?

    5
  • Thursday, Aug 21

    hey so this makes no sense and it makes me want to die

    23
  • Wednesday, Aug 06

    All squares are a type of rectangle but not all rectangles are sqaures!

    2
  • Tuesday, Aug 05

    To much talking..

    0
  • Thursday, Jul 31

    I came back to this at the end of the "Conditional and Set Logic" portion because I was still a little confused on the definitions. But reading it again with the information I have now, the "Let's Review" section makes way more sense. If it's a little confusing now, keep pushing, it might make more sense for you towards the end.

    8
  • Wednesday, Jul 23

    Death liquid tea is a drink, but not all drinks are death liquid tea. Being a drink is necessary to being death liquid tea. Being death liquid tea is sufficient to being a drink.

    6
  • Saturday, Jul 19

    Is there any way I could get a different example so I can better understand this? I find myself falling into the traps of confusing sufficiency for necessity the most.

    2
  • Friday, Jul 18

    so basically to be cat you do not necessarily have to be fat. but in order to be a fat cat it is necessary to be a cat

    5
  • Tuesday, Jul 15

    its like "all squares are rectangles but not all rectangles are squares." you have to be a rectangle to be a square (necessity), but you dont have to be a square to be a rectangle (sufficient) even if you can be.

    9
  • Monday, Jun 23

    I like to think of the necessary element as something that logically or (necessarily follows) the condition of sufficiency. I anticipate that the difficulty lies in distinguishing ambiguous sets and correctly categorizing the relationship. very similar to if then statements.

    0
  • Thursday, May 22

    Correct me if I'm wrong, but this is my understanding:

    If you are in the Empire State Building, it belongs to the subset of NYC and is sufficient for membership in the superset of the USA. However, this is not necessary because you can belong to the superset but not the subset (Grand Canyon)

    Belonging to the Superset (USA) is a necessary condition for membership in the subset (NYC), but the Eiffel Tower is not ‘sufficiently’ eligible for membership in the subset since it does not belong to the superset.

    2
  • Wednesday, May 21

    All cats are sufficiently mammals but not all mammals need to be cats

    It is /enough/ (sufficient) for an animal to be a cat to be considered a mammal

    It is /not enough/ for an mammal to automatically be considered a cat (it needs to be explicitely a cat to be considered a cat)

    8

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