This helped me understand the difference between NA and SA
Say you are buying something that costs $1, it is necessary for you to have the value of 1 cent, but 1 cent is not sufficient. If you have the value of $100, that is sufficient for purchasing the $1 item, but not necessary.
SA and NA overlap if you have exactly $1. $1 is both necessary and sufficient to purchase the item.
I have been so confused on the difference of NA and SA but the analogy that made me clearly understand is this...
A Necessary Assumption (NA) is like life support that keeps a patient alive. It gives the argument a chance to be true, but doesn't guarantee it, as other issues could still arise.
A Sufficient Assumption (SA) is like saying that as long as the patient is on life support, nothing can kill them. This guarantees the argument's conclusion, making it unbreakable.
In summary, an NA keeps the argument viable but not guaranteed, while an SA ensures the argument is conclusive.
#feedback A lot of these sample questions are not available to preview (the small eye icon) so that we can try answering them on our own before watching the video, like they were in the older 7sage website. Would it be possible to add this option again? It's very helpful. Thank you
The reading before this really helped me understand this question right away, I'm finally starting to visualize the right answers before they are even shown.
Hi, are there specific lessons that cover how to identify whether a question uses rule-application reasoning, causal reasoning, conditional reasoning, cost-benefit analysis, and reasoning by analogy? #help Or does anyone have any tips on how to know what kind of question you're dealing with?
Its confusing that he relies so much on past lessons and refers to them often because I'm sure I'm not the only one who wanted to start with necessary assumption before sufficient and because in the lessons sufficient came first he keeps referring to it and its really throwing me off.
@alzayadi444 I too think it's good to do them in order. Him bringing in past lessons actually strengthens our understanding by making the connection of the new with the old, its very good for learning complex concepts (I'm a HS Science Teacher), so def take advantage of his connections by going in order !
@alzayadi444 Agreed - I started with necessary assumption videos because I had trouble with this question type on PTs, and I decided to just follow the whole LR block of curriculum step by step because I believed it would help me better understand necessary assumptions. It really has. They're still hard, but not incomprehensible like they were when I did things out of order.
C is the correct answer because it is better than any of the other answers, but it is not a necessary assumption for the argument. The rule premise, fact premises, and conclusion in the stimulus are about books that recommend composting. Answer C is about any explanation of composting. Lets posit that there exists an explanation that does not recommend composting but does mention it, and gives a basic explanation. That explanation does not include any information about the difference between hot and cold composting. This explanation would violate the rule in answer choice C, but not create any issue with the argument. In formal logic, let RC be recommends compost, EB be explains the basics, EHC be explain the difference between hot and cold. Choice C says for all x, EB(x) -> EHC(x), which we contrapose to ~EHC(x) -> ~EB(x). It is sufficient to make the argument valid. The narrower answer that would be both necessary and sufficient is forall x (RC(x) ^ EB(x)) -> EHC(x), which we contrapose and apply DeMorgan to get ~EHC(x) -> (~RC(x) OR ~EB(x)). This is entirely consistent with natural expectations about what "the basics" mean. The meaning of "basics" depends on the scope. If you're recommending that someone use compost, the basics might be more than if you're just mentioning that compost exists, perhaps to a curious 6 year old who is wondering about the stinky stuff being spread over some field. There the basics might be that compost has nutrients for plants, and sometimes uses smelly things like animal poop. There, you might miss the basics if you didn't explain the smell, but would never be expected to explain hot vs cold composting.
Writing this for my own benefit, but the mistake in intuition I made was thinking necessary assumptions should be making the conclusion incorrect, but they're making the argument incorrect. C) does not make the idea "any gardening book that does not explain the basics is flawed" impossible, since there could be some other basic. But it does make the argument incorrect, since there's no basis in the premises for the conclusion.
The argument really is missing a very important connection in order for the conclusion to follow logically. The conclusion says "some books published by GP are flawed", because P1 they don't explain the difference between hot and cold composting and P2 a gardening book that recommends adding compost needs to explain at least the basics of composting. See how there's an assumption that NEEDS to be made to conclude that some books published by GP are flawed? Explaining the difference between hot and cold composting needs to be (in part or fully) the basics of composting. This is exactly what answer c says, answer e is just saying not flawed gardening book→includes an explanation of at least the basics of composting but that does not help the conclusion follow logically. It is very important to identify the conclusion because that is what you need to strengthen.
So if I am thinking about this correctly, an SA question is a premise that links the other premises to conclusion. However, a NA is a premise that is REQUIRED to conclude the argument?
63 comments
This helped me understand the difference between NA and SA
Say you are buying something that costs $1, it is necessary for you to have the value of 1 cent, but 1 cent is not sufficient. If you have the value of $100, that is sufficient for purchasing the $1 item, but not necessary.
SA and NA overlap if you have exactly $1. $1 is both necessary and sufficient to purchase the item.
Hope this helps someone as much as it helped me!
creds: https://www.youtube.com/watch?v=TjjkE6KGgb4
necessary assumption keeps it alive, sufficient assumption makes it invincible
tbh I preferred when J.Y was aggressively yelling into the mic lol
Agreed Dr. Keedic
This new voice really throws me off.
SA has made me feel fully defeated, hope to redeem myself with NA
im hoping to come back like the 2016 cavaliers in the nba finals after sa questions
mood
Why is JY whispering?
Necessary = a portal that must be open, but doesn't guarantee arrival.
It’s like a required checkpoint — if it’s closed, you can’t go through.
Must be true for the argument to work at all.
Sufficient = a specific path that directly drops you at the goal.
It’s like stepping on a teleportation pad that guarantees you arrive at the conclusion.
Proves the conclusion is true.
I'm retaining NONE of this. Time for a break. Oh boy. I can only take so much butt kicking.
I have been so confused on the difference of NA and SA but the analogy that made me clearly understand is this...
A Necessary Assumption (NA) is like life support that keeps a patient alive. It gives the argument a chance to be true, but doesn't guarantee it, as other issues could still arise.
A Sufficient Assumption (SA) is like saying that as long as the patient is on life support, nothing can kill them. This guarantees the argument's conclusion, making it unbreakable.
In summary, an NA keeps the argument viable but not guaranteed, while an SA ensures the argument is conclusive.
I really like this analogy!
ohhhhh yeah im sooo cooked for the rest of these lessons LMAFOO
@SydneyRoper I believe in you!
#feedback A lot of these sample questions are not available to preview (the small eye icon) so that we can try answering them on our own before watching the video, like they were in the older 7sage website. Would it be possible to add this option again? It's very helpful. Thank you
The reading before this really helped me understand this question right away, I'm finally starting to visualize the right answers before they are even shown.
Damn. You're levelling up. That is the point that great LSAT takers reach. Congrats!
JY still the best teacher even with a sore throat
Hi, are there specific lessons that cover how to identify whether a question uses rule-application reasoning, causal reasoning, conditional reasoning, cost-benefit analysis, and reasoning by analogy? #help Or does anyone have any tips on how to know what kind of question you're dealing with?
^^^^^ #help
Its confusing that he relies so much on past lessons and refers to them often because I'm sure I'm not the only one who wanted to start with necessary assumption before sufficient and because in the lessons sufficient came first he keeps referring to it and its really throwing me off.
#feedback
I did the same thing, it is really helpful to do most of the stuff in order. The curriculum is rly made to be done (mostly) in order.
@Deybomb17 I agree. If you do it in the way the course is set out, it becomes easier to understand because it builds the foundations he refers to.
@alzayadi444 I too think it's good to do them in order. Him bringing in past lessons actually strengthens our understanding by making the connection of the new with the old, its very good for learning complex concepts (I'm a HS Science Teacher), so def take advantage of his connections by going in order !
@alzayadi444 Agreed - I started with necessary assumption videos because I had trouble with this question type on PTs, and I decided to just follow the whole LR block of curriculum step by step because I believed it would help me better understand necessary assumptions. It really has. They're still hard, but not incomprehensible like they were when I did things out of order.
What are all the types of reasoning?
There's rule-application, conditional, causal... Is that it?
Also reasoning by analogy and cost-benefit analysis
Answer choices that bridge conditional gaps between the premises and conclusion are necessary, so (C) is necessary.
https://7sage.com/lsat_explanations/lsat-64-section-3-question-12/
C is the correct answer because it is better than any of the other answers, but it is not a necessary assumption for the argument. The rule premise, fact premises, and conclusion in the stimulus are about books that recommend composting. Answer C is about any explanation of composting. Lets posit that there exists an explanation that does not recommend composting but does mention it, and gives a basic explanation. That explanation does not include any information about the difference between hot and cold composting. This explanation would violate the rule in answer choice C, but not create any issue with the argument. In formal logic, let RC be recommends compost, EB be explains the basics, EHC be explain the difference between hot and cold. Choice C says for all x, EB(x) -> EHC(x), which we contrapose to ~EHC(x) -> ~EB(x). It is sufficient to make the argument valid. The narrower answer that would be both necessary and sufficient is forall x (RC(x) ^ EB(x)) -> EHC(x), which we contrapose and apply DeMorgan to get ~EHC(x) -> (~RC(x) OR ~EB(x)). This is entirely consistent with natural expectations about what "the basics" mean. The meaning of "basics" depends on the scope. If you're recommending that someone use compost, the basics might be more than if you're just mentioning that compost exists, perhaps to a curious 6 year old who is wondering about the stinky stuff being spread over some field. There the basics might be that compost has nutrients for plants, and sometimes uses smelly things like animal poop. There, you might miss the basics if you didn't explain the smell, but would never be expected to explain hot vs cold composting.
Writing this for my own benefit, but the mistake in intuition I made was thinking necessary assumptions should be making the conclusion incorrect, but they're making the argument incorrect. C) does not make the idea "any gardening book that does not explain the basics is flawed" impossible, since there could be some other basic. But it does make the argument incorrect, since there's no basis in the premises for the conclusion.
The argument really is missing a very important connection in order for the conclusion to follow logically. The conclusion says "some books published by GP are flawed", because P1 they don't explain the difference between hot and cold composting and P2 a gardening book that recommends adding compost needs to explain at least the basics of composting. See how there's an assumption that NEEDS to be made to conclude that some books published by GP are flawed? Explaining the difference between hot and cold composting needs to be (in part or fully) the basics of composting. This is exactly what answer c says, answer e is just saying not flawed gardening book→includes an explanation of at least the basics of composting but that does not help the conclusion follow logically. It is very important to identify the conclusion because that is what you need to strengthen.
So if I am thinking about this correctly, an SA question is a premise that links the other premises to conclusion. However, a NA is a premise that is REQUIRED to conclude the argument?
why didn't you diagram the quantifier (some)?
#help Is there any lessons that go over the kind of reasoning the arguments use?
Hi there,
You might find this lesson helpful: Summary and Transition to PSA Questions
I hope this helps. Let me know if you have any further questions or concerns!
Question... on the actual LSAT will I be able to write on the question like so:
@breezyprabahar944 no