@Catherinegsm Yes, I think, so long as Harry has any friends at all. "Some" implies that at least one wizard is his friend. If the majority of his friends are wizards, then at least one wizard is Harry's friend.
You could just imagine "most" as being a more descriptive version of "some". So it's like saying "some of HP's friends are wizards. Therefore some wizards are HP's friend." Some arrows are reversible.
This one is so confusing. Sometimes you're supposed to only use information that the passage gives you, but at other times using outside knowledge is needed...
@timwes21 Harry's muggle life sucked. We know that if you're Harry's friend, then you're probably a wizard. We know that most who are not his friends (most of the world) are muggles.
But all that doesn't mean Draco being a wizard automatically makes it likely that he's Harry's friend. After all, lots of wizards in the world and only so much Harry to go around.
As others mentioned, it's a bit confusing in the opera example with the wording "it seems likely." It's not a solid yes or no conclusion, more of an inference. I wonder if this is common LSAT phrasing?
The opera one is tough because it says "likely", which I would think is something you can say from the information in the premises. "Likely" doesn't mean "we can conclude she is classically trained", its more so "given this information its probable that she is classically trained", which leaves room to still conclude, "she is not classically trained". On the test, I would probably get this wrong because "it seems likely" does a lot of work to make the conclusion make sense.
@isabellagirjikian I actually feel like we lowkey already learned these in video format. Reading it is kind of like reaffirming it in a new context. The effort even might help the material to stick more, especially since it is partially review! 👍🏻
Essentially I saw this is a flipped conditional now reciting the waltz is necessary for being classically trained which is not the case. As the previous lesson stated triggering the Necessary condition yields no valid conclusion.
Another way I thought of it more in an intuitive way was: Okay lets say 51% of classically trained opera singers can recite the waltz and 51% of those who are no classically trained cannot recite the waltz. This doesn't mean that Anna cannot be apart of that group that is classically trained and cannot recite the waltz.
the fact that this entire unit has zero videos is really pissing me off. I paid for a course with videos and instruction, not examples I could ask AI to do for me for free lol.
Based on the sizes of the supersets and "most people who have not received such training cannot" - "It seems likely that Anna was classically trained" sounds pretty reasonable to me
@KaraSwider dude if ur gonna be choosing the size w bias ofc but this is the lsat where its not cut and stone. I can draw the same diagram but with differently sized circles and different amount shaded and cna get the oppisite
In regards to the opera example, I think at the end of the day, there are some problems where you cant look at it from an objective lawgic view and should use your real-world thinking because when I tried to diagram that, I was lost on finding my conclusion :((
@xyzana YES. sometimes using your intuition is a better tool than mapping it out. These modules are just other tools that can help prevent you from confusing sufficiency and necessity, because most times on the test your intuition may not help. These are good to rely on when all else fails.
“Most of Harry Potter's friends are wizards. Most people who are not his friends are not wizards. Therefore, Draco Malfoy, who is a wizard, is probably Harry Potter's friend.”
P1: Friends ‑m→ Wizards
P2: /Friends ‑m→ /Wizards
BUT don't confuse this. You cannot take the counter positive of "most" arguments. They will ALWAYS BE INVALID.
Wizards -m --> Friends
This says... Most wizards are Harry's friends...
Wizards are a BIGGER group than Harry's friends. It's absurd then, to think that most of the wizarding world is Harry's friends.
C: Draco Malfoy (Wizard) → Friend (FALSE)
This is invalid...because in the first premise most of Harry's friends are wizards. The conclusion confuses sufficiency for necessity.
Just because Malfoy is a wizard doesn't mean he is Harry's friend! In the first premise we cannot switch the sufficient condition and the necessary condition It is the same for the 2nd premise as well.
The conclusion is false because those conditions aren't met by the premises.
How would "Most of Harry Potter's friends are wizards. Most people who are not his friends are not wizards. Therefore, Draco Malfoy, who is a wizard, is probably Harry Potter's friend." look like in a subset superset visual? I understand the lawgic but visually I get confused. #help
Most senior-level staff in our office hold graduate-level degrees in Economics or Public Policy. Therefore, Samantha, who has a graduate degree in Economics, is likely to become a senior-level staff member.
112 comments
Go back to using Star Wars examples I don't watch Harry Potter
@ChristianSandlin I was thinking, without my star wars knowledge a lot of this curriculum would have been less helpful for me
is there a video? what is the opera singer argument?
what happened to the video explanations lol
What has been helpful for me to understand these various logic flaws is visualizing by drawing circles
For the HP argument, can I say that most of Harry Potter's friends are wizards. Therefore, some wizards are Harry Potter's friends. Is that valid?
How would it be written out?
@Catherinegsm Yes, I think, so long as Harry has any friends at all. "Some" implies that at least one wizard is his friend. If the majority of his friends are wizards, then at least one wizard is Harry's friend.
You could just imagine "most" as being a more descriptive version of "some". So it's like saying "some of HP's friends are wizards. Therefore some wizards are HP's friend." Some arrows are reversible.
@chris.eveland0 Bet thanks!!
This one is so confusing. Sometimes you're supposed to only use information that the passage gives you, but at other times using outside knowledge is needed...
Ok I need a little more of an explanation from the last example.
@timwes21 Harry's muggle life sucked. We know that if you're Harry's friend, then you're probably a wizard. We know that most who are not his friends (most of the world) are muggles.
But all that doesn't mean Draco being a wizard automatically makes it likely that he's Harry's friend. After all, lots of wizards in the world and only so much Harry to go around.
As others mentioned, it's a bit confusing in the opera example with the wording "it seems likely." It's not a solid yes or no conclusion, more of an inference. I wonder if this is common LSAT phrasing?
@ElianaC I think you can safely replace it seems likely with "most" 51%+ odds would normally be seen as likely to some degree.
@GordonGianadda Thank you, that does make sense
Draco Malfoy being in my LSAT modules was not on my 2026 bingo card
I think it is still the same as confusing sufficiency and necessity.
A - m -->B
A is the sufficient condition for B in the sense that when most of A happens, B happens.
But
it does NOT mean that when most of B happens, A happens.
Example:
Most of my friends are lawyers. Therefore, most of the lawyers are my friends.
my friends - m --> lawyers.
--------------------------------
lawyers - m --> my friends
Invalid!!!!!
I wish most of lawyers were my friends though lols
The opera one is tough because it says "likely", which I would think is something you can say from the information in the premises. "Likely" doesn't mean "we can conclude she is classically trained", its more so "given this information its probable that she is classically trained", which leaves room to still conclude, "she is not classically trained". On the test, I would probably get this wrong because "it seems likely" does a lot of work to make the conclusion make sense.
One thing I've noticed is that they try to trick you with "Most." Most can leave an exception for some.
where are the videos for these? :/
@isabellagirjikian I actually feel like we lowkey already learned these in video format. Reading it is kind of like reaffirming it in a new context. The effort even might help the material to stick more, especially since it is partially review! 👍🏻
How do we deal with "probably" claims, like in the opera example?
could we also say in the opera example, that the conclusion is confusing sufficiency for necessity. In other words, lawgic says:
Classically trained -m-> recite musetta Waltz
/classically trained -m-> /recite musetta Waltz
Conclusion: Recite Musetta waltz (Anna) --> Classically trained
Essentially I saw this is a flipped conditional now reciting the waltz is necessary for being classically trained which is not the case. As the previous lesson stated triggering the Necessary condition yields no valid conclusion.
Another way I thought of it more in an intuitive way was: Okay lets say 51% of classically trained opera singers can recite the waltz and 51% of those who are no classically trained cannot recite the waltz. This doesn't mean that Anna cannot be apart of that group that is classically trained and cannot recite the waltz.
Gosh sorry for the all words!
the fact that this entire unit has zero videos is really pissing me off. I paid for a course with videos and instruction, not examples I could ask AI to do for me for free lol.
#feedback
I think it helps clear this up to say: It could be likely — but it could also be unlikely. and thats the nuance of the LSAT.
@KaraSwider dude if ur gonna be choosing the size w bias ofc but this is the lsat where its not cut and stone. I can draw the same diagram but with differently sized circles and different amount shaded and cna get the oppisite
@JKang bro it literally says "Classically trained opera singers number in the thousands. People who are not so trained number in the billions."
no wonder you guys need videos to make it through - was just trying to add visuals to a section with all text. best wishes.
This entire unit is messed up, why am I paying for lessons I could just ask ChatGPT for or make flash cards for.
In regards to the opera example, I think at the end of the day, there are some problems where you cant look at it from an objective lawgic view and should use your real-world thinking because when I tried to diagram that, I was lost on finding my conclusion :((
@xyzana YES. sometimes using your intuition is a better tool than mapping it out. These modules are just other tools that can help prevent you from confusing sufficiency and necessity, because most times on the test your intuition may not help. These are good to rely on when all else fails.
For the last example...for those WHO NEED HELP:
“Most of Harry Potter's friends are wizards. Most people who are not his friends are not wizards. Therefore, Draco Malfoy, who is a wizard, is probably Harry Potter's friend.”
P1: Friends ‑m→ Wizards
P2: /Friends ‑m→ /Wizards
BUT don't confuse this. You cannot take the counter positive of "most" arguments. They will ALWAYS BE INVALID.
Wizards -m --> Friends
This says... Most wizards are Harry's friends...
Wizards are a BIGGER group than Harry's friends. It's absurd then, to think that most of the wizarding world is Harry's friends.
C: Draco Malfoy (Wizard) → Friend (FALSE)
This is invalid...because in the first premise most of Harry's friends are wizards. The conclusion confuses sufficiency for necessity.
Just because Malfoy is a wizard doesn't mean he is Harry's friend! In the first premise we cannot switch the sufficient condition and the necessary condition It is the same for the 2nd premise as well.
The conclusion is false because those conditions aren't met by the premises.
@OmarAbuaita Thanks for this
How would "Most of Harry Potter's friends are wizards. Most people who are not his friends are not wizards. Therefore, Draco Malfoy, who is a wizard, is probably Harry Potter's friend." look like in a subset superset visual? I understand the lawgic but visually I get confused. #help
It makes sense to me at first, but then when I try to apply Lawgic to explain it, I start to confuse myself lol
Back again with another explanation in hopes of it helping you because it might help me.
The key take away here: Don't read unidirectional arrows backwards
Just because most A are B, does not mean most B are A
Example:
Most of the water I drink is freshwater. Therefore, most freshwater is drank by me.
Lawgic:
Water I drink -m-> Freshwater
-----
Freshwater -m-> Drank by me
Is this valid? Does the premise being true make the conclusion true? NO! THIS IS INVALID.
Just because most of the water I drink is freshwater, DOES NOT MEAN that most of the freshwater is drank by me.
Just because most A are B, DOES NOT MEAN most B are A.
I wish they had videos for these lessons. I'm wasting way too much time trying to confirm if I got the examples right. This is so annoying.
Example:
Most senior-level staff in our office hold graduate-level degrees in Economics or Public Policy. Therefore, Samantha, who has a graduate degree in Economics, is likely to become a senior-level staff member.