With notes and re-reading to make sense of, these lessons take much longer than 2 or 3 minutes. This causes my study plan to be entirely out of reach. #feedback
If I am tall, then I will hit my head on door frames.
T ----> DF
If I do not hit my head on door frames, then I am not tall.
/DF -----> /T
Being Tall is Sufficient, as in it is enough, to then hit my head on door frames. If I am tall, it is necessary that I hit my head on door frames.
If I do not hit my head on door frames, it is Sufficient, as in it is enough to then say, I am not tall. Because it is necessary to NOT be tall if I am NOT hitting my head.
If one thing is necessary for a Sufficient thing, then not having that necessary thing means I cant possibly have the sufficient thing.
Contrapositive is basically saying, the Necessary item is NOT HAPPENING, so the Sufficient one cannot be true.
It took me embarrassingly long to understand this but I want to post it for anybody who is having trouble understanding the "Arrow question"-meaning what happens to the sufficient and necessary titles:
I need to preface that you need to start off with the right premise because i didn't. I didn't understand Conditions. Conditions are not this is sufficient and this is necessary-it's more like this condition causes the other one to happen or be true.
A condition: A situation or state that causes another to have to be true. That's what the LSAT means by conditional logic.
Not Mammal becomes sufficient condition because it's ENOUGH to guarantee Not Cat-BUT it is sufficent because you can be Not Cat in other ways like being a dog. It's a condition because Whenever not mammal happens not cat will happen-thats the condition.
Not Cat is necessary because we know that when Not Mammal is true then Not Cat MUST happen/Be true. That is why it's necessary. When not mammal happens not cat must happen to/has to follow.
If x then Y actually means Xis the trigger (sufficient) - Y is guaranteed (Necessary).
Not mammal -> Not cat ---- means : whenever the condition of not mammal happens, the condition of not cat must also happen
I think this is an important concept because sometimes the multiple choice options on the exam will use the contrapositive version of the correct answer in order to confuse us
I had to think about this one for a bit. The phrase "logically equivalent" took me a bit. The A->B is logically equivalent to /B->/A because the left side guarantees the right side, not that they are trying to reach the same outcome.
This is a very very useful lesson. At least to me, if you CANNOT flip a conditional argument around and still get a logical conclusion, that's telling you something, that the statement is a one-way street
60 comments
"flip it and reverse it" as missy elliott always said
facts
I was coming on here to comment this same thing! I always hear the song in my head when dealing with contrapositives
@maryannmntg33289 wait this is fire thanks diva
If one is pulling out their hair, then one is studying for the LSAT.
PTH —> LSAT
If one is not studying for the LSAT, then one is not pulling out their hair
/LSAT —> /PTH
With notes and re-reading to make sense of, these lessons take much longer than 2 or 3 minutes. This causes my study plan to be entirely out of reach. #feedback
If I am tall, then I will hit my head on door frames.
T ----> DF
If I do not hit my head on door frames, then I am not tall.
/DF -----> /T
Being Tall is Sufficient, as in it is enough, to then hit my head on door frames. If I am tall, it is necessary that I hit my head on door frames.
If I do not hit my head on door frames, it is Sufficient, as in it is enough to then say, I am not tall. Because it is necessary to NOT be tall if I am NOT hitting my head.
If one thing is necessary for a Sufficient thing, then not having that necessary thing means I cant possibly have the sufficient thing.
Contrapositive is basically saying, the Necessary item is NOT HAPPENING, so the Sufficient one cannot be true.
@SimonArmendariz Ser Dunk, is that you? lol
from A knight of the seven kingdoms show
The "See you in the next lesson" caught me off guard lol
It took me embarrassingly long to understand this but I want to post it for anybody who is having trouble understanding the "Arrow question"-meaning what happens to the sufficient and necessary titles:
I need to preface that you need to start off with the right premise because i didn't. I didn't understand Conditions. Conditions are not this is sufficient and this is necessary-it's more like this condition causes the other one to happen or be true.
A condition: A situation or state that causes another to have to be true. That's what the LSAT means by conditional logic.
Not Mammal becomes sufficient condition because it's ENOUGH to guarantee Not Cat-BUT it is sufficent because you can be Not Cat in other ways like being a dog. It's a condition because Whenever not mammal happens not cat will happen-thats the condition.
Not Cat is necessary because we know that when Not Mammal is true then Not Cat MUST happen/Be true. That is why it's necessary. When not mammal happens not cat must happen to/has to follow.
If x then Y actually means Xis the trigger (sufficient) - Y is guaranteed (Necessary).
Not mammal -> Not cat ---- means : whenever the condition of not mammal happens, the condition of not cat must also happen
If I am drinking coffee, then I am awake.
If C--> A
If I am not awake, then I am not drinking coffee
If /A --> /C
If there is sun outside, then it must be a great day.
SO > GD
If it not a great day, then there is no sun outside
/GD > /SO
what is the difference between formally equivalent and logically equivalent?
If I am harvesting wheat, I am working hard.
HW -> WH
If I am NOT working hard, I am NOT harvesting wheat.
/WH -> /HW
If one eats buffalo chicken cheese fries, then they must be my good friend Kileki.
BCCF>K
If one is NOT my good friend Kileki, then they must've NOT eaten buffalo chicken cheese fries.
/K>/BCCF
Valid contrapositive argument, false claim lol. We love forms!
If I am pale, then I am sick.
P -> S
If I am not Sick, then I am not pale.
/S -> /P
I think this is an important concept because sometimes the multiple choice options on the exam will use the contrapositive version of the correct answer in order to confuse us
@Shawndeo5 I think you're def right
If I am playing soccer, then I am wearing cleats.
PS --> WC
If I am NOT wearing cleats, then I am NOT playing soccer
If I am at my desk studying for the LSAT, my cats will be sitting on my desk.
D -> C
If my cats are not sitting on my desk, then I am not at my desk studying for the LSAT.
/C -> /D
Conditional Claim: If one drinks coffee in the morning, then one has energy for the day.
Contrapositive: If one does not have energy for the day, then one did not drink coffee in the morning.
-drinking coffee in the morning is sufficient for having energy for the day.
-having energy for the day is necessary for drinking coffee in the morning.
If i am studying for the LSAT, I have a coffee
SL --> C
If I am not having a coffee, I am not studying for the LSAT
/C --> /SL
Would this be logically equivalent:
If one is not a cat then they are a reptile
(Lawgic: /C —> R)
Contra:
If one is not a reptile then they are a cat.
(Lawgic: /R —> C)
Yes thats correct
If I am in NYC, then I am in the USA
NYC --> USA
Being in the USA is necessary to be in NYC
Being in NYC is sufficient to be in the USA
/USA --> /NYC
Not being in the USA means I am not in NYC
I had to think about this one for a bit. The phrase "logically equivalent" took me a bit. The A->B is logically equivalent to /B->/A because the left side guarantees the right side, not that they are trying to reach the same outcome.
This is a very very useful lesson. At least to me, if you CANNOT flip a conditional argument around and still get a logical conclusion, that's telling you something, that the statement is a one-way street
If I am walking outside, then I am wearing shoes
WO -> WS
If I am not wearing shoes, then I am not walking outside
/WS -> /WO
If I have a drivers license, then I can legally drive.
DL -> LD
so the contrapositive = flip+negate
/LD -> /DL
I cannot legally drive if I do not have a drivers license
If I am studying for the LSAT, I'm in my office
SL->O
If I am not in my office, I am not studying for the LSAT
/O->/SL
To understand this better I would watch lessons on YouTube of DeMorgan's Law, its very helpful!
link: https://www.youtube.com/watch?v=93CxSLi89Ok