@JuliaLambert Just found this in my notes from earlier in the course: "No contrapositives for quantifiers "some" and "most"; contrapositives are just for conditional claims.
@LegallyLawyer Assuming the - is "<- s ->," then no, since the correct way to negate X-Wing -> hyperdrives is to change the -> to <- s -> and to negate only the second item
@KennedyLuther you are taking the contrapositive instead of negation. for negation, you just have to "prove" that the first statement is not true (to keep it simple). so to negate this, you basically have to say no thats false. some x wings don't have hyperdrives. or an easier example would be (all dogs are white). no, thats false! some dogs actually are not white.
I understand how logically in question one it could be that zero X-wings have hyperdrives, but we previously said that "some" is exclusive of zero. So is it case by case dependent of when "some" includes and does not include zero?
At first I was really confused on how I could use the lesson on negating "some" statements to get to the answer in Question 2.
After revisiting I think I understand. Writing this out for my own sake (and anyone who could find it helpful).
This is the translation rule in the lesson:
A <-s-> B = /(A<-s->B) = A --> /B
This is the translation in Question Two:
A <-s-> /P = /(A<-s->/P) = A --> P
Translation back to English:
A --> P = All alphabets are phonetic
I think part of the confusion is that based on the translation rule, I was expecting to end with a negated necessary condition (i.e. /B). But in the case of question two, P (which is substituted in for B), was already negated. Meaning, after going through the process of negation in step two, you end up with P rather than /P.
I would negate this as just "Some pilots are blind".
Is there really a difference between "Some pilots are blind" and "One can be a pilot and blind"?
I actually feel the latter is not correct. It just states a possibility, not a negation of fact. Its possible that "One can be a pilot and blind", however still be try that "No pilots are blind". Just because its possible, does not mean its ever happened.
@danjpeach96 I think both of the claims "some pilots are blind" and "one can be a pilot and blind" both actively show how the claim "no pilots are blind" can be false! say if you are claiming that "oh, no pilots are blind" and i say "actually i know someone who is a pilot and blind" then i am directly refuting your claim (and also negating it!). That possibility of even one person being a pilot and blind negates the claim that no pilots are blind! i hope this makes sense :)
@mostxareyallyarezthusmostxarez Yeah can be false is not false, just an ability to be so. "Can be P and B" is not a negation. I think "One is a pilot and is blind" is what was meant. That is P and B. I don't know it probably doesn't matter.
If you can be blind and be a pilot, but there are no blind pilots then "No pilots are blind" is true. No getting around that
SO confused on this. It was never mentioned that 'some' is the negated version of 'all.' I understand how that makes sense but I'm starting believe these lessons aren't very comprehensive.
@ShanR It's there, but perhaps a little easy to miss. In the negating "all" lesson, it says that the negation of "All dogs are friendly" is not "No dogs are friendly", but is instead "Some dogs are not friendly"
@CaleighFreeman I think it's fine if you understand it, and understand the relationship between "It's not the case that everyone enjoys the movies" and "some people do not enjoy the movies," etc.
@AnthonyFlores I think it's important to remember that in terms of "Quantifier" All and No are the same concept, one is just positive and one is negative. They are inverse versions of each other that mean the same thing. No alphabets are not phonetic and All alphabets are phonetic mean the same thing!
Hi all, I made another flashcard set. This time for memorizing Quantifiers. Flashcards are what really helped me in undergrad and so I decided to make them to companion my 7sage studies. Thought I'd share to help others who would benefit :) made a folder that I will most likely add more sets to as I go. Much Love and happy studying! https://quizlet.com/user/ehoffmanwallace/folders/lsat-7sage-flashcards
what is the importance of knowing whether you are dealing with a conditional claim or quantifier member in sets, if A some B and A and /B are basically the same?
@Oblivion Can you elaborate on your question? Just to be clear, "No A is B" = "All A are NOT B." Those two mean the same thing.
But if we're asked to negate the whole statement (like we are in this quiz), we have to think about what it means for "No A is B" to be false. The negation of "No A is B" = "Some A are B."
272 comments
There are no contrapositives of logic involving quantifiers, am I right?
@JuliaLambert Just found this in my notes from earlier in the course: "No contrapositives for quantifiers "some" and "most"; contrapositives are just for conditional claims.
In the Quantifier Inference Lesson, we are taught that All implies Most. So why in Q#1 is it some?
5/5 AYEE
For question 1 my final translation was wordier than it should be; I got "At most some X-wings have hyperdrives."
I think I got it
@TeklaCo you mind explaining?
@8M_M8 which one?
@TeklaCo #1 and #4, if possible.
Did I miss this lesson, Im so confused
Guys, can #1 not be /H-/X?
@LegallyLawyer Assuming the - is "<- s ->," then no, since the correct way to negate X-Wing -> hyperdrives is to change the -> to <- s -> and to negate only the second item
I cant lie.... this is probs the first lesson I got 0 correct, and was genuienly confused by the correct answer
i swore we learned
All X-Wings have hyperdrives.
X > H
/H > X
if you dont have hyperdrives, youre not an x wing
is that not the case??
@KennedyLuther you are taking the contrapositive instead of negation. for negation, you just have to "prove" that the first statement is not true (to keep it simple). so to negate this, you basically have to say no thats false. some x wings don't have hyperdrives. or an easier example would be (all dogs are white). no, thats false! some dogs actually are not white.
"Some alphabets are not phonetic."
"All alphabets are phonetic. (A → P)"
bro what. if some are not, then clearly not all can be phonetic. This makes no sense
This is the most confusing thing ever
I understand how logically in question one it could be that zero X-wings have hyperdrives, but we previously said that "some" is exclusive of zero. So is it case by case dependent of when "some" includes and does not include zero?
At first I was really confused on how I could use the lesson on negating "some" statements to get to the answer in Question 2.
After revisiting I think I understand. Writing this out for my own sake (and anyone who could find it helpful).
This is the translation rule in the lesson:
A <-s-> B = /(A<-s->B) = A --> /B
This is the translation in Question Two:
A <-s-> /P = /(A<-s->/P) = A --> P
Translation back to English:
A --> P = All alphabets are phonetic
I think part of the confusion is that based on the translation rule, I was expecting to end with a negated necessary condition (i.e. /B). But in the case of question two, P (which is substituted in for B), was already negated. Meaning, after going through the process of negation in step two, you end up with P rather than /P.
#help I have problems on these:
No pilots are blind.
I would negate this as just "Some pilots are blind".
Is there really a difference between "Some pilots are blind" and "One can be a pilot and blind"?
I actually feel the latter is not correct. It just states a possibility, not a negation of fact. Its possible that "One can be a pilot and blind", however still be try that "No pilots are blind". Just because its possible, does not mean its ever happened.
@danjpeach96 I think both of the claims "some pilots are blind" and "one can be a pilot and blind" both actively show how the claim "no pilots are blind" can be false! say if you are claiming that "oh, no pilots are blind" and i say "actually i know someone who is a pilot and blind" then i am directly refuting your claim (and also negating it!). That possibility of even one person being a pilot and blind negates the claim that no pilots are blind! i hope this makes sense :)
@mostxareyallyarezthusmostxarez Yeah can be false is not false, just an ability to be so. "Can be P and B" is not a negation. I think "One is a pilot and is blind" is what was meant. That is P and B. I don't know it probably doesn't matter.
If you can be blind and be a pilot, but there are no blind pilots then "No pilots are blind" is true. No getting around that
Part 1
Part 2
These videos on youtube by Kevin are helpful!
@paligrrl This was SUPER helpful! Thank you!
SO confused on this. It was never mentioned that 'some' is the negated version of 'all.' I understand how that makes sense but I'm starting believe these lessons aren't very comprehensive.
@ShanR It's there, but perhaps a little easy to miss. In the negating "all" lesson, it says that the negation of "All dogs are friendly" is not "No dogs are friendly", but is instead "Some dogs are not friendly"
@SavanahHoffstein Thank you
5/5, yay!!
lawgic really helps for #2. the rest i didn't need lawgic for
Is it okay to answer the questions with "It's not the case that..."?
@CaleighFreeman I think it's fine if you understand it, and understand the relationship between "It's not the case that everyone enjoys the movies" and "some people do not enjoy the movies," etc.
can someone explain question 2 for me? I thought the negation of "some" was "no," right?
@AnthonyFlores Yes the negation of "some" is "none" or "no".
Original statement: Some alphabets are not phonetic. aka 1%-100% of alphabets are not phonetic
A <--s--> /P
Negation: No alphabets are not phonetic. aka 0% of alphabets are not phonetic -- No A are /P
Using "No" as it is a conditional indicator from group 4 where we negate the necessary condition,
A --> P, (All) Alphabets are phonetic.
@AnthonyFlores I think it's important to remember that in terms of "Quantifier" All and No are the same concept, one is just positive and one is negative. They are inverse versions of each other that mean the same thing. No alphabets are not phonetic and All alphabets are phonetic mean the same thing!
Hi all, I made another flashcard set. This time for memorizing Quantifiers. Flashcards are what really helped me in undergrad and so I decided to make them to companion my 7sage studies. Thought I'd share to help others who would benefit :) made a folder that I will most likely add more sets to as I go. Much Love and happy studying! https://quizlet.com/user/ehoffmanwallace/folders/lsat-7sage-flashcards
@Elideebeep Thank you so much, I found these very helpful. gave me confirmation that I am learning something.
what is the importance of knowing whether you are dealing with a conditional claim or quantifier member in sets, if A some B and A and /B are basically the same?
Q2 ?
No alphabets are not phonetic = All alphabets are phonetic
Q3? No = All ?
@Oblivion Can you elaborate on your question? Just to be clear, "No A is B" = "All A are NOT B." Those two mean the same thing.
But if we're asked to negate the whole statement (like we are in this quiz), we have to think about what it means for "No A is B" to be false. The negation of "No A is B" = "Some A are B."
@Oblivion I think you are confusing that "No A" means /A, which is not the case. "No" is instead a conditional indicator (Group 4) so
For your Q2, "no alphabets are not phonetic" does mean "All alphabets are phonetic".
No A are /P. & "No" is a Group 4 conditional indicator meaning that we negate the necessary and in this case that then makes it: A --> P
you gave 2 methods to negate an all, yet on question one, when i did it one way, it just used the other and is telling me i am wrong.
@JiggityJack5 Can you elaborate? What is the one way you negated the statement in Question 1?
the fact that a different person is answering this and not using the concepts we just covered is very confusing