On the LSAT, how would we know when to negate the conclusion (/F -> /Jedi) and how do we know when to negate the whole claim like it does in this lesson?
For those confusing negation with the contrapositive:
the contrapositive is when we negate the necessary condition, which in turn negates the sufficient condition. (A-->B turns into /B-->/A) The contrapositive also allows us to understand logically equivalent claims.
When we negate "a claim about a relationship" we are not negating the necessary condition but rather the claim itself. For example, a biologist may say if cat then mammal, (C-->M) but a science skeptic may negate that and say it is not the case that if cat then mammal (C and /M).
When you attempt to negate a claim about a relationship, in this instance, a conditional relationship, you are trying deny that relationship. Same error is present in the same section of the previous lesson on "all" relationships.
I understand the difference between Negating conditional statements and taking the Contrapositive but in a question how would I know which method to use if they use the same indicator words (e.g. If-then)?
Could it also be framed as if J then F and negated as if /J and F meaning one does not need to be a Jedi to use the force? or is this wrong to negate the sufficient condition? I believe this may not work because writing /A and B could suggest not A and not B.
#feedback, with conditional the statements can I accurately negate only the " necessary condition" and not have to bother about the sufficient condition, all the time?
Why is this different from negating "all" claims in the previous section? I thought "all" was an indicator of a sufficient condition, so "All A are B" = A --> B, which is the same as "If A then B"
(i.e. "All cats are mammals" is the same as "If one is a cat, then they are a mammal")
#feedback From my understanding, negating a conditional statement (whether all, some, many, most) means that there has been at leastttt one exception where the rule (ex: If A then B) doesn't hold as opposed to negating all (or some, or most, or many, etc) to none, right?
Okay I get it now a negation is basically saying not that. so dogs are friendly the negation would be the dogs are not friendly which means that the negation is the false statement right but how is that relevant
Does anyone know a way to visually represent this with circles that would represent sets? Similar to what he did in the previous lesson about negating all?
So I understand that here we are negating the relationship - but when do we know whether to negate the relationship or if its just a contrapositive conditional or necessary statement such as: where A–> B turns into /B–>/A? And I remember a lesson earlier saying don't apply real world common knowledge to come to an answer - instead use what we have and are being told. makes sense, but for here it says to be a Jedi one must be able to use the force. So why are we negating the relationship and when will we need to?
Ok so I understand how this is different from the other thing we learned where A--> B turns into /B-->/A, but how does this compute for my notes? Like in which cases do we use both of these? Why would I be doing a negation like in this video?
Does "all," not imply sufficiency and necessity, then? I'm confused as to why "all" translates the same as "if" into lawgic but it's negated differently.
Can someone point out an LSAT question where this would occur or be helpful to know.
0
Topics
PT Questions
Select Preptest
You've discovered a premium feature!
Subscribe to unlock everything that 7Sage has to offer.
Hold on there, stranger! You need a free account for that.
We love that you want to get going. Just create a free account below—it only takes a minute—and then you can continue!
Hold on there, stranger! You need a free account for that.
We love that you came here to read all the amazing posts from our 300,000+ members. They all have accounts too! Just create a free account below—it only takes a minute—and then you’re free to discuss anything!
Hold on there, stranger! You need a free account for that.
We love that you want to give us feedback! Just create a free account below—it only takes a minute—and then you’re free to vote on this!
Subscribers can learn all the LSAT secrets.
Happens all the time: now that you've had a taste of the lessons, you just can't stop -- and you don't have to! Click the button.
114 comments
On the LSAT, how would we know when to negate the conclusion (/F -> /Jedi) and how do we know when to negate the whole claim like it does in this lesson?
Where do we learn about the concepts behind conditional vs set differences?
it is so messed up, i am still very confused with negating the conditional r/s.
For those confusing negation with the contrapositive:
the contrapositive is when we negate the necessary condition, which in turn negates the sufficient condition. (A-->B turns into /B-->/A) The contrapositive also allows us to understand logically equivalent claims.
When we negate "a claim about a relationship" we are not negating the necessary condition but rather the claim itself. For example, a biologist may say if cat then mammal, (C-->M) but a science skeptic may negate that and say it is not the case that if cat then mammal (C and /M).
Months later still coming back to review this
Found a typo under the "Let's Review"
When you attempt to negate a claim about a relationship, in this instance, a conditional relationship, you are trying deny that relationship. Same error is present in the same section of the previous lesson on "all" relationships.
#feedback
I understand the difference between Negating conditional statements and taking the Contrapositive but in a question how would I know which method to use if they use the same indicator words (e.g. If-then)?
Does the negation use a similar principle to simplify embedded conditionals?
Could you also negate this example to J ←s→ /F?
Could it also be framed as if J then F and negated as if /J and F meaning one does not need to be a Jedi to use the force? or is this wrong to negate the sufficient condition? I believe this may not work because writing /A and B could suggest not A and not B.
#feedback, with conditional the statements can I accurately negate only the " necessary condition" and not have to bother about the sufficient condition, all the time?
Why is this different from negating "all" claims in the previous section? I thought "all" was an indicator of a sufficient condition, so "All A are B" = A --> B, which is the same as "If A then B"
(i.e. "All cats are mammals" is the same as "If one is a cat, then they are a mammal")
#feedback From my understanding, negating a conditional statement (whether all, some, many, most) means that there has been at leastttt one exception where the rule (ex: If A then B) doesn't hold as opposed to negating all (or some, or most, or many, etc) to none, right?
Okay I get it now a negation is basically saying not that. so dogs are friendly the negation would be the dogs are not friendly which means that the negation is the false statement right but how is that relevant
So basically, NC doesn't follow from SC???
Does anyone know a way to visually represent this with circles that would represent sets? Similar to what he did in the previous lesson about negating all?
So I understand that here we are negating the relationship - but when do we know whether to negate the relationship or if its just a contrapositive conditional or necessary statement such as: where A–> B turns into /B–>/A? And I remember a lesson earlier saying don't apply real world common knowledge to come to an answer - instead use what we have and are being told. makes sense, but for here it says to be a Jedi one must be able to use the force. So why are we negating the relationship and when will we need to?
I understand this well, but what types of situations am I gonna be needing to negate conditional statements?
Ok so I understand how this is different from the other thing we learned where A--> B turns into /B-->/A, but how does this compute for my notes? Like in which cases do we use both of these? Why would I be doing a negation like in this video?
This is unfortunately not naturally intuitive for me, are there any exercises on this?
I feel like nobody is going to understand this but I just figured out that J.Y. sounds so similar to Martin from Slushynoobz. Maybe I am crazy...
In previous grammar videos to negate is to switch the positions. Like A -> B it would be /A -> /B
When does that apply? why is it that negating in this scenario is just denying the relationship?
is this correct negation too ;- to not be a jedi one must be a force user. /J -> F
Does "all," not imply sufficiency and necessity, then? I'm confused as to why "all" translates the same as "if" into lawgic but it's negated differently.
Can someone point out an LSAT question where this would occur or be helpful to know.