so basically, your job isn't to decide whether the statements are true or false. Instead, you're focused on analyzing the structure of the argument to determine if it's logically valid.
A valid or invalid argument depends on the STRUCTURE of the argument!
So: If A then B. X is A. Therefore, X is B. (Valid)
But: If A then B. X is C. Therefore, X is A. (invalid) -- this is invalid because we don't know the relationship between C and A.
If this same argument read like:
If A then B. If C then also A. X is C. Therefore, X is A. (it becomes valid)
because of the structure. I try to avoid the word "truth" all together:
If a person is a boy (if A), then the person is a bottle of lotion (then B). If one smells like vanilla (if C) then one is also a boy (then also A). Samantha smells like vanilla (X is a member of C), therefore Samantha is a boy. (X is A).
Technically, this is a valid argument...but far from the truth. But the structure allows for the conclusion to logically follow the premises.
@AidenG123 Sorry just seeing this, yes! There are many ways to make an argument valid.
Another thing that can help me is to write it out side by side. The boy is the sufficient condition/subset to Lotion (Necessary condition/Superset) in P1. Then in P2, the lotion is a sufficient condition/subset to Vanilla (Necessary condition/Superset). So, here you have lotion as both a superset and subset which is fine [see lesson on sets].
In some cases, it can be helpful to write the premises in one row:
For me, writing it side by side when it is simple like this, makes it easier to see that the conclusion is guaranteed. In your example we can literally see the conclusion.
Boy (A) --> Lotion (B) --> Vanilla (C) [see lesson on chaining arguments]
The plans for a building cannot be "true" or "untrue." They can, however, be structurally sound (valid) or structurally unsound (invalid).
Now, I tell you I'm going to build a house in Wonderland. I show you the blueprint. It is mathematically and structurally perfect—i.e., valid. If Wonderland were real, it would work flawlessly. And that validity is totally irrelevant to the "truth" of my premises, being that Wonderland is a real place I can build a house in.
If an argument is valid, it means the argument is logically correct (The premise supports the conclusion and does not contradict one another.) Even though the premises are false, it can still be a valid argument.
Is it even worth reading all of these passages before continuing onto exercises and practice tests again after the diagnostic? I feel like I am reading a bunch but am not able to apply any of it right after learning about it.
I agree with you, it's hard to actually grasp concepts without an exercise afterwards. I will occasionally ask chatgpt to create sample questions on each topic which has helped me a lot.
Aw man, I skipped these foundational lessons for the sake of time and I'm glad I'm reviewing them now. I would get questions wrong on a factual basis, and was really confused why the test wanted me to believe things that made no factual sense. Thank you, 7Sage!
If you're struggling with the information clicking, I would recommend watching again. The biggest point of this is that the reasoning is the most important thing when trying to determine if something is valid. Wether it is true or false doesn't necessarily matter because we aren't looking at most arguments from a real world lense anyways.
Maybe I missed it in the video, but for me it is also important to understand that just like a valid argument can have false premises, an invalid argument can have true premises.
Important to be on the lookout for this. Just because the premises and conclusion of an argument are all true does not guarantee the validity of the argument. If I told you that:
A. cats are mammals
and
B. siamese is breed of cat
then
C. Burmese cats are mammals
All these things are true, but the logic of the argument is flawed and therefore invalid.
I agree that valid arguments can have false premises and vice versa. However, if we consider that the conclusion Burmese cats are mammals is a logical truth, then despite whatever the premises are it is a valid argument. For an argument with a logically true conclusion regardless of the premises, it will not change the truth of the conclusion. It is definitely a terribly reasoned and unsound argument, yet it is valid.
I think it would be useful to apply the technical term 'soundness' here in place of truth. In formal logic and philosophy, an argument is sound if it is valid and the premises are true. This is for the LSAT and most of us don't care so much about the philosophical underpinnings of these relationships, but with the technical term people could do more personal research about arguments without being confused when they come across the term 'sound'.
basically, pretend that the convo ur having w ur friend (the lsat question) is indeed true and ur just making sure that they didn't leave out or switch up any critical parts of the story (evaluating premise content and overall reasoning formula for conditional argument) ???
How I am understanding this is even though the premises can be false, as long as the premises match the conclusion, it is a valid argument. You aren’t looking if the actual claims are “true” or factually correct. You are looking at the form of the argument and if the premises support the conclusion. If it does, then it's a valid argument.
It is really freeing to not assess whether or not something is true and instead consider if something is valid or not. It allows you to just assume the test is giving you enough baseline for knowledge and reject assumptions that could arise and lead you askew
I think I understand what the lesson is trying to say, but are we supposed to just believe that even if the arguments are "false," as long as they are "valid" we just have to accept the argument? #help
I like to also think of it like the test can't expect you to know everything out there about every topic. So if it brings up an argument about art history, it's not assessing whether you know if the claims about art history being made are true, but whether the argument itself is valid.
Some detachment from the ACTUAL world you know of to be true can be of great benefit in assessing the validity of arguments. When analyzing the validity or invalidity of an argument you need to sideline what you might know to be true about a particular statement within that argument and ask yourself "IF it were the case in some POSSIBLE world that the premises that support this conclusion were true, would the conclusion follow necessarily?" If it would then the argument is valid if it wouldn't then its invalid.
Validity does not equal to truth. However, if all premises are true then the conclusion must be true. This makes an argument valid. An invalid argument depends on the truth of the premises.
really like the part where they said "validity is (if(or pretend that)) all the premises are true". good way to remind yourself to remove bias and other logic and whatever you read is the truth and nothing else.
This part is so hard to accept because my brain immediately refuses to accept the argument based of the falsehoods it generated. The truth is all teenage mutant turtles are ninjas. But the LSAT is rage baiting by saying nah just turtles just to trick people judging the truth.
74 comments
so basically, your job isn't to decide whether the statements are true or false. Instead, you're focused on analyzing the structure of the argument to determine if it's logically valid.
Put differently, Validity means the premise logically supports the conclusion. (The math makes sense.)
What helps me is to think of it like this:
A valid or invalid argument depends on the STRUCTURE of the argument!
So: If A then B. X is A. Therefore, X is B. (Valid)
But: If A then B. X is C. Therefore, X is A. (invalid) -- this is invalid because we don't know the relationship between C and A.
Technically, this is a valid argument...but far from the truth. But the structure allows for the conclusion to logically follow the premises.
@16dnholli would the argument be made valid If it said all bottles f lotion smell like vanilla?
This would make the chain
P1:Boy (A) --> Lotion (B)
P2: Lotion (B) --> Vannilla (C)
C: A --> C?
@AidenG123 Sorry just seeing this, yes! There are many ways to make an argument valid.
Another thing that can help me is to write it out side by side. The boy is the sufficient condition/subset to Lotion (Necessary condition/Superset) in P1. Then in P2, the lotion is a sufficient condition/subset to Vanilla (Necessary condition/Superset). So, here you have lotion as both a superset and subset which is fine [see lesson on sets].
In some cases, it can be helpful to write the premises in one row:
P1:Boy (A) --> Lotion (B) ; P2: Lotion (B) --> Vanilla (C);
Therefore: Boy (A) --> Vanilla (C)
For me, writing it side by side when it is simple like this, makes it easier to see that the conclusion is guaranteed. In your example we can literally see the conclusion.
Boy (A) --> Lotion (B) --> Vanilla (C) [see lesson on chaining arguments]
The plans for a building cannot be "true" or "untrue." They can, however, be structurally sound (valid) or structurally unsound (invalid).
Now, I tell you I'm going to build a house in Wonderland. I show you the blueprint. It is mathematically and structurally perfect—i.e., valid. If Wonderland were real, it would work flawlessly. And that validity is totally irrelevant to the "truth" of my premises, being that Wonderland is a real place I can build a house in.
@AnnabelleNeidl Great way to put it
@AnnabelleNeidl
You probably just raised somebody's LSAT score like 5 points, by yourself, lol.
@AnnabelleNeidl Goated comment
My favorite way someone told me to to remember this is "attack the argument, not the premises."
@AndreaGuillen805 love this
thank you to freshman me for wanting to be a philosophy major instead of a polisci major
I think the technical descriptions / the deep dives make me more confused honestly
Same
so its still a good rule of thumb to not use your outside knowledge on the test?
@KeziaH19 yup
So essentially the premises is not an assumption ever, it is the truth.
If an argument is valid, it means the argument is logically correct (The premise supports the conclusion and does not contradict one another.) Even though the premises are false, it can still be a valid argument.
Is it even worth reading all of these passages before continuing onto exercises and practice tests again after the diagnostic? I feel like I am reading a bunch but am not able to apply any of it right after learning about it.
I agree with you, it's hard to actually grasp concepts without an exercise afterwards. I will occasionally ask chatgpt to create sample questions on each topic which has helped me a lot.
Aw man, I skipped these foundational lessons for the sake of time and I'm glad I'm reviewing them now. I would get questions wrong on a factual basis, and was really confused why the test wanted me to believe things that made no factual sense. Thank you, 7Sage!
If you're struggling with the information clicking, I would recommend watching again. The biggest point of this is that the reasoning is the most important thing when trying to determine if something is valid. Wether it is true or false doesn't necessarily matter because we aren't looking at most arguments from a real world lense anyways.
Maybe I missed it in the video, but for me it is also important to understand that just like a valid argument can have false premises, an invalid argument can have true premises.
Important to be on the lookout for this. Just because the premises and conclusion of an argument are all true does not guarantee the validity of the argument. If I told you that:
A. cats are mammals
and
B. siamese is breed of cat
then
C. Burmese cats are mammals
All these things are true, but the logic of the argument is flawed and therefore invalid.
I agree that valid arguments can have false premises and vice versa. However, if we consider that the conclusion Burmese cats are mammals is a logical truth, then despite whatever the premises are it is a valid argument. For an argument with a logically true conclusion regardless of the premises, it will not change the truth of the conclusion. It is definitely a terribly reasoned and unsound argument, yet it is valid.
I think it would be useful to apply the technical term 'soundness' here in place of truth. In formal logic and philosophy, an argument is sound if it is valid and the premises are true. This is for the LSAT and most of us don't care so much about the philosophical underpinnings of these relationships, but with the technical term people could do more personal research about arguments without being confused when they come across the term 'sound'.
From my understanding with the help of chat and broke it down for me easily!
Think of it like a pattern:
If A → B
X is A
→ therefore X is B ✅
This is valid because it follows the rule correctly.
🧩 Example (simple)
If it rains → ground is wet
It is raining
→ ground is wet ✅
This makes sense AND is logically valid.
🚫 Invalid example
If A → B
X is C
→ therefore X is A ❌
Why is this wrong?
Because:
👉 we don’t know how C relates to A
There’s no connection.
🔁 When it becomes valid
If A → B
If C → A
X is C
→ therefore X is A ✅
Now it works because:
C leads to A
X is C
so X must be A
basically, pretend that the convo ur having w ur friend (the lsat question) is indeed true and ur just making sure that they didn't leave out or switch up any critical parts of the story (evaluating premise content and overall reasoning formula for conditional argument) ???
How I am understanding this is even though the premises can be false, as long as the premises match the conclusion, it is a valid argument. You aren’t looking if the actual claims are “true” or factually correct. You are looking at the form of the argument and if the premises support the conclusion. If it does, then it's a valid argument.
Pls correct me if I am wrong.
So would I be incorrect to day A claim cam be false but still have a valid arguments?
It is really freeing to not assess whether or not something is true and instead consider if something is valid or not. It allows you to just assume the test is giving you enough baseline for knowledge and reject assumptions that could arise and lead you askew
I think I understand what the lesson is trying to say, but are we supposed to just believe that even if the arguments are "false," as long as they are "valid" we just have to accept the argument? #help
basically yes. remember it's not the content that matters, but the form of the argument!
I like to also think of it like the test can't expect you to know everything out there about every topic. So if it brings up an argument about art history, it's not assessing whether you know if the claims about art history being made are true, but whether the argument itself is valid.
You can accept the reasoning of an argument (because it's valid) while rejecting the premises of the argument (because they are false).
Some detachment from the ACTUAL world you know of to be true can be of great benefit in assessing the validity of arguments. When analyzing the validity or invalidity of an argument you need to sideline what you might know to be true about a particular statement within that argument and ask yourself "IF it were the case in some POSSIBLE world that the premises that support this conclusion were true, would the conclusion follow necessarily?" If it would then the argument is valid if it wouldn't then its invalid.
Yes, excellent point.
Validity does not equal to truth. However, if all premises are true then the conclusion must be true. This makes an argument valid. An invalid argument depends on the truth of the premises.
On each question then essentially make myself blind to all prior knowledge.
really like the part where they said "validity is (if(or pretend that)) all the premises are true". good way to remind yourself to remove bias and other logic and whatever you read is the truth and nothing else.
This part is so hard to accept because my brain immediately refuses to accept the argument based of the falsehoods it generated. The truth is all teenage mutant turtles are ninjas. But the LSAT is rage baiting by saying nah just turtles just to trick people judging the truth.