For #5, I understand why everyone enjoys the movies negates to some people do not enjoy movies, but if some goes both ways (Person <-s-> /enjoy movies), does this also say that "Some who do not enjoy movies are people?" That doesn't make sense to me conceptually, since I feel like that implies that some who do not enjoy movies are not people, and that makes no sense. If anyone has an answer, please reply
I don't truly understand why in questions 1 and 2 it can't be "no A are B" I know what I'm supposed to do, but I don't understand why it CANT be no?
If we are negating
"some A are not B"
saying "no A are B" WOULD negate that...right?? I know I'm missing something small but at this point I feel like I'm just memorizing and not UNDERSTANDING. idk id love some help if anyone could explain
QUESTION: in question number 3, the answer says SOME PILOTS ARE BLIND, but we agreed that some could go to the extent of covering ALL, so that would not be negating the initial statement
Can we really infer from ~[ALL X-WINGS HAVE HYPERDRIVES] to [SOME X-WINGS DON'T HAVE HYPERDRIVES]? The former statement says having a hyperdrive isn't a necessary condition for something to be an x-wing. But the latter statement says there exists some x-wing without a hyperdrive. In other words, we're inferring the existence of hyperdrive-less x-wings from a statement which is silent on whether or not they exist.
so the negation would be at least some and at least many people don't enjoy the movies
but why not 'no people enjoy the movies' as the negation of 'all people enjoy the movies'
I just looked back at my notes from lesson 16 and I see what the flaw in my quetsion is
If A then B
the contrapositive is if not B then not A
that would be the logical equivalent to
All people like movies
no people dont like movies
But we are not looking for the contrapositive, or a negation of one set, we are looking for a negation of the relationship between the two sets
all people enjy the movies
its not the case that all people enjoy the movies
the negation of the claim is at least some, perhaps many or perahps all don't enjoy movies
but if we made the claim 'all people don't enjoy movies' we aren't including all the possibilities of the negation of the set of 'all'
bc whose to say its not some & not many?
or whose to say its not many & not all?
It can be all, but doesn't have to be all
therefore, the valid negation of 'all people enjoy movies' is not 'no people enjoy movies' but rather 'some people don't enjoy movies'
Pro tip - if you are still confused, look back to the lesson on 'all'. I just did that and it helped. Heres why.
All is used as a conditional indicator for sufficient claims
All dogs are mammals
D>M
the negation of that couldn't possibly be:
if you are a dog then you are not a mammal
instead the negation would read:
Some mammals are not dogs
the example given in the negation of all lesson was if the quantified statement you are looking at reads:
All dogs are friendly
it wouldn't be correct to negate it by saying
all dogs are not friendly
instead you would have to say 'some dogs are not friendly'
saying all dogs are not friendly is negating something about group dog -- we dont care about group dog. we care about group dog as it relates to group friendly. Negation is about relationships. So, if you were to negate group dog as being not friendly, that doesnt help me with negation. Instead, I have to negate the fact that in every case group dog overlaps with group friendly by saying 'some dogs are not friendly'. some could mean all.
abnd back in Lesson 4 we stated that
some can include all (depending on the contxt)
so perhaps that is a simplified way of looking at this quetsion
For question number 4, would it also be correct to end up with M-->/F. As far as I can tell that is logically equivalent to /M-->F. I know that technically speaking "not fat" is a different superset from "fat," so this answer would involve changing the necessary as opposed to the sufficient condition. That being said, I cannot find a logical flaw in answering /M-->F, which also has the added benefit of translating more clearly to english. Please let me know if you see any issues here!
With the same logic for #4, the originally claim would be M ←s→ F, to negate it, I thought it would be different, but after looking at my notes, it would be A→/B aka M → /F.
However, I am still stuck on the answer for #2. How would I have confused the answer when it is the same process as #4?
In the Negating Some video it tells us the negation of some is "a-/b" and in question two the negation turns to "All". I am so confused where that came from since in the video on negating some "All" was not mentioned. BUT in question 4 the negation of some turns into "a-/b" (which to my understanding from the negating some video is how it should be) so what is the difference between the two questions?
For Question 1: I'm a bit confused about why the negation of "All" is "Some" in the context of denying a relationship. Since "Some" can refer to any number from 1 to 100, wouldn’t that range still include the possibility of "All," making it seem like the relationship isn't fully denied? I understand that using "No" as the negation would ignore the full spectrum of possibilities, but I’m a bit confused about how denying a relationship can still allow for the possibility of it occurring. Thank you in advance to anyone who can clear this up!
I made the mistake of translating #3 into /p --> b, when it was supposed to be p --> /b.
I did that because "no pilots" sounded like a negation of the group pilots. Had it read all pilots are not blind, I might not have made that mistake. Can you please explain my mistake? Why was I wrong for writing /p --> b?
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213 comments
Can someone explain how in this, "Some alphabets are not phonetic.", the not phonetic became just phonetic? Really struggling with the double negation
For #5, I understand why everyone enjoys the movies negates to some people do not enjoy movies, but if some goes both ways (Person <-s-> /enjoy movies), does this also say that "Some who do not enjoy movies are people?" That doesn't make sense to me conceptually, since I feel like that implies that some who do not enjoy movies are not people, and that makes no sense. If anyone has an answer, please reply
I don't truly understand why in questions 1 and 2 it can't be "no A are B" I know what I'm supposed to do, but I don't understand why it CANT be no?
If we are negating
"some A are not B"
saying "no A are B" WOULD negate that...right?? I know I'm missing something small but at this point I feel like I'm just memorizing and not UNDERSTANDING. idk id love some help if anyone could explain
QUESTION: in question number 3, the answer says SOME PILOTS ARE BLIND, but we agreed that some could go to the extent of covering ALL, so that would not be negating the initial statement
Will we be taught in a future lesson how this can be applied to LSAT questions? Because I am currently not seeing it.
4/5 the double negative in question 2 got me.
I too am confused. I thought "All" negates to "Some".
X-Wings -> Have Hyperdrives
X-wings <- s -> have hyperdrives
I don't understand why it would be X-wings <- s -> /have hyperdrives ???
I'm confused why some of these have two answers.
why is "everyone" in #5 translated to some and not most? Wouldn't everyone seem like most?
[This comment was deleted.]
5/5!!!
Can we really infer from ~[ALL X-WINGS HAVE HYPERDRIVES] to [SOME X-WINGS DON'T HAVE HYPERDRIVES]? The former statement says having a hyperdrive isn't a necessary condition for something to be an x-wing. But the latter statement says there exists some x-wing without a hyperdrive. In other words, we're inferring the existence of hyperdrive-less x-wings from a statement which is silent on whether or not they exist.
#feedback
Some alphabets are not phonetic.
alphabets ←s→ /phonetic
/phonetic ←s→ alphabets
alphabets → phonetic
/phonetic → /alphabets (Is the contrapositive useful here?)
#feedback
If all negates to some, then does some negate to all?
for example all A are B negates to some A are not B
then if
Some A are not B then all A are B?
Could "All" not be negated by saying "Not all" which seems to be similar to "some"?
would it be true/ can you say a negation of #5:
all people enjoy the movies
could be
no people enjoy the movies?
all includes some and includes many
so the negation would be at least some and at least many people don't enjoy the movies
but why not 'no people enjoy the movies' as the negation of 'all people enjoy the movies'
I just looked back at my notes from lesson 16 and I see what the flaw in my quetsion is
If A then B
the contrapositive is if not B then not A
that would be the logical equivalent to
All people like movies
no people dont like movies
But we are not looking for the contrapositive, or a negation of one set, we are looking for a negation of the relationship between the two sets
all people enjy the movies
its not the case that all people enjoy the movies
the negation of the claim is at least some, perhaps many or perahps all don't enjoy movies
but if we made the claim 'all people don't enjoy movies' we aren't including all the possibilities of the negation of the set of 'all'
bc whose to say its not some & not many?
or whose to say its not many & not all?
It can be all, but doesn't have to be all
therefore, the valid negation of 'all people enjoy movies' is not 'no people enjoy movies' but rather 'some people don't enjoy movies'
Pro tip - if you are still confused, look back to the lesson on 'all'. I just did that and it helped. Heres why.
All is used as a conditional indicator for sufficient claims
All dogs are mammals
D>M
the negation of that couldn't possibly be:
if you are a dog then you are not a mammal
instead the negation would read:
Some mammals are not dogs
the example given in the negation of all lesson was if the quantified statement you are looking at reads:
All dogs are friendly
it wouldn't be correct to negate it by saying
all dogs are not friendly
instead you would have to say 'some dogs are not friendly'
saying all dogs are not friendly is negating something about group dog -- we dont care about group dog. we care about group dog as it relates to group friendly. Negation is about relationships. So, if you were to negate group dog as being not friendly, that doesnt help me with negation. Instead, I have to negate the fact that in every case group dog overlaps with group friendly by saying 'some dogs are not friendly'. some could mean all.
abnd back in Lesson 4 we stated that
some can include all (depending on the contxt)
so perhaps that is a simplified way of looking at this quetsion
For question number 4, would it also be correct to end up with M-->/F. As far as I can tell that is logically equivalent to /M-->F. I know that technically speaking "not fat" is a different superset from "fat," so this answer would involve changing the necessary as opposed to the sufficient condition. That being said, I cannot find a logical flaw in answering /M-->F, which also has the added benefit of translating more clearly to english. Please let me know if you see any issues here!
good explanation on #2 thanks
Question 1... is X ←s→ H
(some X-wings have hyperdrives) the logical equivalent of
X ←s→ /H
(some X-wings don't have hyperdrives) b/c both imply the existence of some X-wings having and some not having hyperdrives?
#2 and #4 are somewhat confusing.
To negate #2, wouldn't it be /(A ←s→P)?
With the same logic for #4, the originally claim would be M ←s→ F, to negate it, I thought it would be different, but after looking at my notes, it would be A→/B aka M → /F.
However, I am still stuck on the answer for #2. How would I have confused the answer when it is the same process as #4?
#help!!!
In the Negating Some video it tells us the negation of some is "a-/b" and in question two the negation turns to "All". I am so confused where that came from since in the video on negating some "All" was not mentioned. BUT in question 4 the negation of some turns into "a-/b" (which to my understanding from the negating some video is how it should be) so what is the difference between the two questions?
I hope that made sense
For Question 1: I'm a bit confused about why the negation of "All" is "Some" in the context of denying a relationship. Since "Some" can refer to any number from 1 to 100, wouldn’t that range still include the possibility of "All," making it seem like the relationship isn't fully denied? I understand that using "No" as the negation would ignore the full spectrum of possibilities, but I’m a bit confused about how denying a relationship can still allow for the possibility of it occurring. Thank you in advance to anyone who can clear this up!
#help
Can someone explain question #5 as I made the mistake of assuming everyone is all. Im just kinda of confused by how it translates to some.
I made the mistake of translating #3 into /p --> b, when it was supposed to be p --> /b.
I did that because "no pilots" sounded like a negation of the group pilots. Had it read all pilots are not blind, I might not have made that mistake. Can you please explain my mistake? Why was I wrong for writing /p --> b?
Makes sense!