I felt like I had a good grasp on flaws in formal arguments and could pin point the issue in these Qs but kept getting tripped up by the wording in the AC. This lesson I realized 2 things (that might have already been clear) but that I hope help anyone running into the similar issues.
1. The flaw of negating the sufficient condition is equivalent to sufficient/necessary confusion.
Argument: A -> B
Flaw of Denying Sufficient: /A -> /B when contraposed is just B -> A
2. Since they are interchangeable, the alternative phrasing for A in the lesson is just saying that the arg negated the sufficient condition
Arg confuses that under certain conditions (A) an action will be taken (B) (A->B) with a claim that in the absence of that condition (/A) that action won't be taken (/B) (/A -> /B). Contrapose back, it becomes B -> A
This might not be new info but hope it helps anyone that might have initially overlooked this like I did.
i feel like the reason people get this wrong in a timed scenario is not that it is logically complicated but that answer choice A looks like a trap. A is so obviously stating something in the way most people learn about suff and necc that it feels like a trick. Trying to psychoanalyze the test that you feel is designed to make you question everything may really get to people in said high pressure situation.
Yesss 36 Seconds. Practice, practice, practice Sufficient and Neccesary until it infects your dreams guys! No shame in going back to those initial lessons :)
can someone break down necessary condition vs sufficient for me again in simple terms? I will feel confident understanding it just to get it wrong again
@joannaw something that is sufficient is enough to prove the necessary condition. A common example is cat -> mammal. If you are a cat, it is 100% guaranteed you are a mammal. Cat is sufficient to being a mammal.
Being a mammal, on the other hand, is NOT proof that you are a cat. If you are a mammal, that cannot be used to prove you are also a cat. Mammal -/> cat. This is because being a mammal is the necessary condition, or otherwise stated as being the superset.
For this question specifically, Majority of Citizens Favor the Proposal -> Airport is Built. However, the conclusion the stimulus reaches is that /Majority of Citizens Favor the Proposal -> /Airport is Built. If you contropose this, this is identical to saying Airport is built -> Majority of Citizens Favor the Proposal, AKA the exact opposite of the premise
so far i have a perfect score on formal flaw questions but a zero on informal flaw questions... what am i doing wrong? why isnt informal makes sense to me the way formal is?!
#help okay I am getting tripped up because I feel like so many of these are simply “confusing suf. for nec.”
For ex. this question and like two questions ago - I was choosing A. Then consciously decided to change my answer, thinking there is no way there is this many confusing suf. for nec. and maybe I am being tricked.
#Feedback. So the flaw in this question is that the argument didn't Negate B first and then negate A. But instead Negated A and then B, which is not how sufficient/necessary rules work.
@IsabellaP Hi! Yes, I think that's correct. The argument is exhibiting a common pattern of flawed reasoning where the author says: if A then B, so if NOT A, then not B. That's incorrect because negating the sufficient condition (A) doesn't tell us anything about the necessary condition (B). For example: All cats (A) are mammals (B). Therefore, if an animal is not a cat (not A), then it is not a mammal (not B). That's an incorrect conclusion. However, it would be correct to say: if an animal is not a mammal (not B), then it is not a cat (not A). Negating the necessary condition allows us to negate the sufficient condition.
In this argument, the author says: if majority in favor --> build airport. NOT majority in favor --> NOT build airport. (aka if A, then B. Not A. Therefore, not B). If instead of negating the sufficient condition (residents in favor) the author had negated the necessary condition (the airport won't be built), they could have correctly concluded that the majority of the residents were not in favor.
Yayyyyy once again this brought me joy! I am currently 29% through the RC section and I am continuing to crash out. There’s a lot more information to retain and comprehend with the long passages compared to LR. The drills are making me lose it a bit but we hang in there. WE GOT THIS!!!!
This entire section has helped me realize just how important it is to avoid the sufficiency-necessity confusion. Thankfully, it's starting to stick out like a sore thumb now. Thanks, JY!
This unit was not too difficult imo. Though I went over target time because I was between A and C but glad I noticed A was literally what the whole argument was concluding.
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98 comments
I felt like I had a good grasp on flaws in formal arguments and could pin point the issue in these Qs but kept getting tripped up by the wording in the AC. This lesson I realized 2 things (that might have already been clear) but that I hope help anyone running into the similar issues.
1. The flaw of negating the sufficient condition is equivalent to sufficient/necessary confusion.
Argument: A -> B
Flaw of Denying Sufficient: /A -> /B when contraposed is just B -> A
2. Since they are interchangeable, the alternative phrasing for A in the lesson is just saying that the arg negated the sufficient condition
Arg confuses that under certain conditions (A) an action will be taken (B) (A->B) with a claim that in the absence of that condition (/A) that action won't be taken (/B) (/A -> /B). Contrapose back, it becomes B -> A
This might not be new info but hope it helps anyone that might have initially overlooked this like I did.
The single time my formal logic training made me diagram and actually helped me
i feel like the reason people get this wrong in a timed scenario is not that it is logically complicated but that answer choice A looks like a trap. A is so obviously stating something in the way most people learn about suff and necc that it feels like a trick. Trying to psychoanalyze the test that you feel is designed to make you question everything may really get to people in said high pressure situation.
Yesss 36 Seconds. Practice, practice, practice Sufficient and Neccesary until it infects your dreams guys! No shame in going back to those initial lessons :)
Got it right through POE
Getting 43 seconds under target feels SO GOOD after getting basically nothing right in NA qs 😭
"I'm speechless. I feel like it's my birthday." I felt that to my core.
@LSATbae123 fr
am i the only one that instantly got this right, i did it 26 seconds under the recommended lol
i keep confusing myself with these suff necess questions :(
i hate doing LSAT. come hell or high water i will be taking this test in may or june of next year and im done i cant take it anymore
@Jupiter24 maybe take a week off and come back.
lmao idk why I struggle w 2 star questions but will do okay on 4 or 5 stars :(((((
can someone break down necessary condition vs sufficient for me again in simple terms? I will feel confident understanding it just to get it wrong again
@joannaw something that is sufficient is enough to prove the necessary condition. A common example is cat -> mammal. If you are a cat, it is 100% guaranteed you are a mammal. Cat is sufficient to being a mammal.
Being a mammal, on the other hand, is NOT proof that you are a cat. If you are a mammal, that cannot be used to prove you are also a cat. Mammal -/> cat. This is because being a mammal is the necessary condition, or otherwise stated as being the superset.
For this question specifically, Majority of Citizens Favor the Proposal -> Airport is Built. However, the conclusion the stimulus reaches is that /Majority of Citizens Favor the Proposal -> /Airport is Built. If you contropose this, this is identical to saying Airport is built -> Majority of Citizens Favor the Proposal, AKA the exact opposite of the premise
@NathanielWright This was so helpful, thank you!
so far i have a perfect score on formal flaw questions but a zero on informal flaw questions... what am i doing wrong? why isnt informal makes sense to me the way formal is?!
POE was the only way i got this tbh
it took me forever to do this question because i saw the word dalton and immediately started hearing a capella in my head #isitoverforme
#help okay I am getting tripped up because I feel like so many of these are simply “confusing suf. for nec.”
For ex. this question and like two questions ago - I was choosing A. Then consciously decided to change my answer, thinking there is no way there is this many confusing suf. for nec. and maybe I am being tricked.
Does anyone else feel like this?
these flaw questions eating me uppp :(
mightve only been 3 seconds under, but we got it right baby
Idk how to explain it but I just felt in my soul that there was a sufficient necessity confusion and went with A LMAO.
#Feedback. So the flaw in this question is that the argument didn't Negate B first and then negate A. But instead Negated A and then B, which is not how sufficient/necessary rules work.
Is this thinking correct?? Thanks!
@IsabellaP Hi! Yes, I think that's correct. The argument is exhibiting a common pattern of flawed reasoning where the author says: if A then B, so if NOT A, then not B. That's incorrect because negating the sufficient condition (A) doesn't tell us anything about the necessary condition (B). For example: All cats (A) are mammals (B). Therefore, if an animal is not a cat (not A), then it is not a mammal (not B). That's an incorrect conclusion. However, it would be correct to say: if an animal is not a mammal (not B), then it is not a cat (not A). Negating the necessary condition allows us to negate the sufficient condition.
In this argument, the author says: if majority in favor --> build airport. NOT majority in favor --> NOT build airport. (aka if A, then B. Not A. Therefore, not B). If instead of negating the sufficient condition (residents in favor) the author had negated the necessary condition (the airport won't be built), they could have correctly concluded that the majority of the residents were not in favor.
55 seconds off target but i DONT CARE i got it right ive been struggling with this wholeeee section ahhhhhh
I love seeing ur comments
This gave me joy i am so glad you enjoy my comments i will continue to be crashing out in these comment sections <3
Yayyyyy once again this brought me joy! I am currently 29% through the RC section and I am continuing to crash out. There’s a lot more information to retain and comprehend with the long passages compared to LR. The drills are making me lose it a bit but we hang in there. WE GOT THIS!!!!
bro u r my king
where are you in your studies now?? i also love seeing ur comments haha. are you in the RC section now? if so, how do you like it?!
This entire section has helped me realize just how important it is to avoid the sufficiency-necessity confusion. Thankfully, it's starting to stick out like a sore thumb now. Thanks, JY!
35 secs btw ;P
23 secs under
24
Nice job friend, keep up the good work
29
This unit was not too difficult imo. Though I went over target time because I was between A and C but glad I noticed A was literally what the whole argument was concluding.
Got it in under a minute 😮💨