the " failing a sufficient condition means nothing but failing a necessary condition yield's valid conclusions" genuinely shifted the way I have thought about suff/nec for the last year of studying wow. this is SO helpful
I’m a little confused I keep doing it back ways like I did ED YT F J but like I understood it the same but I don’t want to mixed it up for the test so I’m a little confused on knowing when J or F is supposed to be on right or left
In the first example, which would be more correct between A (not a force user) and C (not a jedi)?
I know the LSAT is so focused on choosing the best answer even if more than one are correct, so im curious if its better to go with the more direct answer or the most complicated/comprehensive one.
I liked that these examples showed conditional indicators that don't always act in that capacity. It helps to be able to practice distinguishing when it acts as an indicator and when it's just a word. I like to bold and underline indicators and italicize them when they are just a word as I do these practice questions.
To be a Jedi, one must be a Force user. Becoming a Force user requires years of training, which further requires extraordinary discipline. Tom has only received six months of training in the Force. Therefore, Tom ____.
"Only" does not act as an indicator
The vote to grant Chancellor Palpatine emergency powers will not pass if Senator Amidala delivers her speech. Amidala cannot deliver her speech unless the attempt to assassinate her fails. Her assassins planted a bomb on her starship but unbeknownst to them, she was not on the ship when the explosive detonated. Therefore, the vote to grant the Chancellor emergency powers will not pass.
I find it harder translating into logic than reading the stimulus sometimes... I think my challenges for the LSAT may rely on understanding what they're asking me to figure out. The logic itself makes sense to me just because the assassination failed doesn't mean she's going to give her speech they're may be other factors...
In the second sentence of Exercise 2 I counted "cannot" as a Group 4 meaning I negated the necessary condition automatically. I still came to the same conclusion, that the argument was invalid.
But it has been helpful to learn that whenever there are two negation indicators that they cancel themselves out. (Admittedly I also missed "unless"). I'm not sure if that has been explicitly said before this lesson, maybe I've just missed it, but this was certainly the first time I have heard about this rule.
I see a lot of confusion on this lesson, which caught me by surprise. It seems so far what we've learned is that you can go right but not left (goes back to the superset/subset idea taught earlier). So if there is no condition of her giving the speech given another condition like "If the planted bomb attempt fails, Amidala will deliver her speech" (AAF -> SAS) then we cannot conclude she does deliver her speech. That's how it worked in my head, given that the argument used wording such as "cannot deliver" instead of "will deliver".
Sorry if that was super long. But hopefully this helps anybody who is having any difficulty on this one.
Would the conclusion become valid if after "her assassins planted a bomb..." there were a sentence about how she later gave the speech? This would trigger the sufficient condition of SAS --> /P.
@Dexterity Wouldn't the first statement "Failing a condition triggers everything to its left. (<---)" need to be qualified by saying "triggers everything to its left, but negated?"
Does anyone advise memorizing the indicators (and their categories) although they are under/overinclusive? Or is practice a better strategy to getting the hang of these to avoid constantly referring to my notes?
Is this just confusing sufficient for necessity? The way I see it as an invalid conclusion is because we don't know if she delivered her speech, we just know that the assassination attempt failed.
For simple terms/understanding, is the second problem invalid because it is 'assuming' she would deliver her speech? If there was a premise that said, "If the assassination attempt fails, then she will deliver her speech". Would that therefore make it a valid conclusion? This is how I understood it...
My gut instinct was that we couldn't say for certain that the bomb on her starship was the assassination attempt on her... not that she might not have given the speech...
@elena That was the first part, it is not stated that it was the attempt, the only attempt, or the last assassination attempt. Secondly there is nothing to state her actual course of action. There is nothing stating she will be giving a speech in the first place. A very lazy way to try to make it work (but fail) is using contextualized inference which usually leads us down the wrong logic path.
In question 2, since the necessary condition is what is stated and it does not refer to the sufficient condition. We cannot infer whether SAS or /p is true. So is that why we have an invalid conclusion?
I get Lawgic, except for the "unless" sort of stuff, the group 2 rules. I feel like I can never properly identify what needs to be negated or what is just natural.
I got the answer in my head, but found the lawgic confusing with nothing to ad. That said, I hope that learning/memorizing the process, as described, will help with questions I might struggle with. I guess the symbols did narrow the frame to a single key question about one of the premises, and that could be helpful.
i think the reason why i got the second exercise wrong because of the statement saying that based on the information alone, is the conclusion valid. the information given (assassination attempt failed and that was the only the written to be a factor in the vote not passing), to me, makes the conclusion valid. this is hard!
I am still confused on why this is invalid. My understanding is that because SAS is sufficient, she could be doing other things that are not SAS and still satisfy AAF? Since the conclusion is based on the sufficient condition, which cannot always be true, therefor the conclusion is invalid?? Could someone explain this a little more?
@OwenTrela How I understood it was that we ended up confusing necessity and sufficiency - that AAF is necessary for SAS, but that it is not sufficient evidence to affirm that SAS.
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263 comments
the " failing a sufficient condition means nothing but failing a necessary condition yield's valid conclusions" genuinely shifted the way I have thought about suff/nec for the last year of studying wow. this is SO helpful
@bellaens18 do you mind explaining this a little further? i'm confused.
I’m a little confused I keep doing it back ways like I did ED YT F J but like I understood it the same but I don’t want to mixed it up for the test so I’m a little confused on knowing when J or F is supposed to be on right or left
We KNOW something if:
Necessary condition FAILS to occur
Sufficient condition OCCURS
WE DON'T KNOW something if:
Necessary Condition OCCURS
Sufficient condition FAILS to occur
@Cee🦋 This makes so much sense ur amazing
@Cee🦋 Hi, can you please use this in an example? I'm trying to wrap my head around this. Thank you!
In the first example, which would be more correct between A (not a force user) and C (not a jedi)?
I know the LSAT is so focused on choosing the best answer even if more than one are correct, so im curious if its better to go with the more direct answer or the most complicated/comprehensive one.
@MaggieRhodes Came to the comment section wondering the same thing. I assume its whichever one is the direct sufficient condition but I am not 100%.
I liked that these examples showed conditional indicators that don't always act in that capacity. It helps to be able to practice distinguishing when it acts as an indicator and when it's just a word. I like to bold and underline indicators and italicize them when they are just a word as I do these practice questions.
"Only" does not act as an indicator
"Cannot" does not act as an indicator
I find it harder translating into logic than reading the stimulus sometimes... I think my challenges for the LSAT may rely on understanding what they're asking me to figure out. The logic itself makes sense to me just because the assassination failed doesn't mean she's going to give her speech they're may be other factors...
In the second sentence of Exercise 2 I counted "cannot" as a Group 4 meaning I negated the necessary condition automatically. I still came to the same conclusion, that the argument was invalid.
But it has been helpful to learn that whenever there are two negation indicators that they cancel themselves out. (Admittedly I also missed "unless"). I'm not sure if that has been explicitly said before this lesson, maybe I've just missed it, but this was certainly the first time I have heard about this rule.
I see a lot of confusion on this lesson, which caught me by surprise. It seems so far what we've learned is that you can go right but not left (goes back to the superset/subset idea taught earlier). So if there is no condition of her giving the speech given another condition like "If the planted bomb attempt fails, Amidala will deliver her speech" (AAF -> SAS) then we cannot conclude she does deliver her speech. That's how it worked in my head, given that the argument used wording such as "cannot deliver" instead of "will deliver".
Sorry if that was super long. But hopefully this helps anybody who is having any difficulty on this one.
so is this saying she CAN give a speech but theres no proof she DOES? @Kevin_Lin
@KimberlyLoki222 Right. We know IF she gives a speech, that requires the assassination attempt to fail.
The assassination attempt failed. But that doesn't prove she gave a speech. There's no statement telling us, "If ________, then she'll give a speech."
Would the conclusion become valid if after "her assassins planted a bomb..." there were a sentence about how she later gave the speech? This would trigger the sufficient condition of SAS --> /P.
@EmeryBeals Yes. We'd need something telling us she gave the speech. Otherwise, there's no way for us to infer that she must have given the speech.
Whenever you're dealing with logic chains like these, it helps a ton to remember these rules of thumb:
Failing a condition negates everything to its left. (<---)
Satisfying a condition triggers everything to its right. (--->)
@Dexterity Hey! Do you think you can give me an example of this?
Thank you.
@JosieAzar Picture this chain:
A --> B --> C
Failing B yields the inference that A, which is left of B, is also failed, because that's how sufficiency/necessity works. If A > B, then /B > /A.
Satisfying B yields the inference that C, which is right of B, is also satisfied, because that's also how sufficiency/necessity works.
lost me big time
[This comment was deleted.]
@Dexterity Wouldn't the first statement "Failing a condition triggers everything to its left. (<---)" need to be qualified by saying "triggers everything to its left, but negated?"
please remind me to go back to this
@Bicakum03 come back
Does anyone advise memorizing the indicators (and their categories) although they are under/overinclusive? Or is practice a better strategy to getting the hang of these to avoid constantly referring to my notes?
@Kellbell206 I would definitely memorize. You just can't get around it.
Is this just confusing sufficient for necessity? The way I see it as an invalid conclusion is because we don't know if she delivered her speech, we just know that the assassination attempt failed.
Writing the contrapositive for q1 helped me a lot
@EllenSCola same, i feel like the video explanation overcomplicated it
For simple terms/understanding, is the second problem invalid because it is 'assuming' she would deliver her speech? If there was a premise that said, "If the assassination attempt fails, then she will deliver her speech". Would that therefore make it a valid conclusion? This is how I understood it...
@vonRentzell Correct
My gut instinct was that we couldn't say for certain that the bomb on her starship was the assassination attempt on her... not that she might not have given the speech...
@elena That was the first part, it is not stated that it was the attempt, the only attempt, or the last assassination attempt. Secondly there is nothing to state her actual course of action. There is nothing stating she will be giving a speech in the first place. A very lazy way to try to make it work (but fail) is using contextualized inference which usually leads us down the wrong logic path.
In question 2, since the necessary condition is what is stated and it does not refer to the sufficient condition. We cannot infer whether SAS or /p is true. So is that why we have an invalid conclusion?
I get Lawgic, except for the "unless" sort of stuff, the group 2 rules. I feel like I can never properly identify what needs to be negated or what is just natural.
I got the answer in my head, but found the lawgic confusing with nothing to ad. That said, I hope that learning/memorizing the process, as described, will help with questions I might struggle with. I guess the symbols did narrow the frame to a single key question about one of the premises, and that could be helpful.
i think the reason why i got the second exercise wrong because of the statement saying that based on the information alone, is the conclusion valid. the information given (assassination attempt failed and that was the only the written to be a factor in the vote not passing), to me, makes the conclusion valid. this is hard!
Lawgic is still confusing to me too.
I am highly confused with lawgic, I had it and then took a little break and came back and lost it all.
I am still confused on why this is invalid. My understanding is that because SAS is sufficient, she could be doing other things that are not SAS and still satisfy AAF? Since the conclusion is based on the sufficient condition, which cannot always be true, therefor the conclusion is invalid?? Could someone explain this a little more?
@OwenTrela How I understood it was that we ended up confusing necessity and sufficiency - that AAF is necessary for SAS, but that it is not sufficient evidence to affirm that SAS.