Can we never negate rules? It can never be "/Should not PJ" and that would then become "Should PJ" so we would know what that is? Or is that for any formal logic but rules?
@DakshMalik I also was confused with this at first, but I think he's saying that "Should play joke" can never be a necessary condition. If we were to negate the conclusion, "/Should PJ" (should not PJ), then "Should PJ" would become a sufficient condition, and not a conclusion.
First, you said that since this is a conjunction ("Or"), if either condition is triggered, we can conclude that the jokes "should not have played." When you evaluated answer A, you said "even if it was not contemptuous" is useless and pointed to the diagram you made. Why should "not contemptuous" have been useless? Yes, it doesn't meet our condition, but until there, the answer is actually fine. Since we needed either condition, it is fine that the joke was "not contemptuous." The answer messes up on the second condition. Could you please clarify why you struck the "even if it was not contemptuous" line?
I was also choosing between B and C and the MAIN reason I baked away from C was b/c it said "show contempt to ANYONE" guys...the principle said "that person" though... the person the joke is being played on. So wouldn't that be wrong?! helppp
@mahi0615 C is still correct because if the joke doesn't show contempt for "anyone" than we can assume it doesn't show contempt for that one person, because it shows contempt for no one! Therefore, that piece of the application fits the stimulus. (Note: this is different from D listing "someone" is shown contempt because we cannot assume that this is or isn't the "someone" that the joke is being played on).
B has an unreachable conclusion in that not fulfilling the "contempt" or "harm" conditions does not guarantee that the prank should be played.
Love the little aside on the prescriptive "should". From my perspective, it's useful to think about should vs ought. Should, strictly understood, is subjective guidance defeasible for a good reason. Ought, strictly understood, is an objective authority giving a moral imperative (that can only be defeated with a superior moral imperative). But they overlap. Especially in modern usage, should can be used to mean ought. If should is being used in a principle, it could mean guidance (you should bring an umbrella), or it could mean it's a moral imperative (you shouldn't hit people), and you're going to have to look elsewhere for the clues as to which one is meant.
@JesseMcCarthy You can take the contrapositive which would be " should play joke -> /contempt and /believe it would cause harm " but that would not allow us to conclude that a joke should be played because the "should be" condition is sufficient and on the left side of the arrow.
shows contempt or believes harm --> /play practical joke
basically if shows c or believes h than do not play practical joke
contrapositive =
if play practical joke --> /show contempt and /believe harm
basically if you play practical joke then we know it does not show contempt and one does not believe harm.
AC B. is wrong because the original argument and the contrapositive DOES NOT assert when it would be wrong for one to play a joke. We just know what makes one not be able to play a practical joke and if one does do it what it should not have. AC. B. states it would not be wrong for me to play it but we do not know when it would be wrong.
woah this one was kind of hard. but once i went back and realized it said "to that person" and not "to anyone/someone" all the other answer choices fell apart.
Although I got it right, I'm curious when do we know a conclusion is unreachable? If it because this is an "or" statement? Why doesn't the contrapositive work in this circumstance?
@rjon27 update: i found the answer from a tutor on the discussion board for the question itself. Basically, still take the contrapositive but make sure to note if an answer choice is confirming the sufficient conditions (left side of the arrow) or the necessary conditions (right side of the arrow). B says that the necessary conditions are met but that doesn't mean the joke can be played. Hope this helps!
Tutor Answer:
Contrapositives are ALWAYS valid to use in answering any type of question. For this question, you started with a correct diagram of the stimulus:
Shows contempt OR believes it will bring significant harm -> /ok to play practical joke
The contrapositive of this is:
ok to play practical joke -> /show contempt AND /believe it will bring significant harm
Answer choice B shows the necessary conditions are satisfied. But if the necessary conditions for X are satisfied, that DOES NOT mean we can infer X. This is what 7Sage calls the "oldest trick in the book"—confusing necessary and sufficient conditions. You can read more about this common mistake here in our Argument Flaw Cheat Sheet: https://7sage.com/lessons/logical-reasoning/flaw-or-descriptive-weakening-questions/argument-flaw-cheat-sheet
Or you can apply the Jackass Negation: One should always play a practical joke on someone, especially if it shows contempt and/or could bring significant harm to that person. ;)
For B to be correct it would have to have the following structure: Since it would not be wrong for me to play the practical joke, it must be that the joke would show no contempt for the person it is played on and that I have no reason to think it would bring significant harm to anyone.
@legallyhaya it may be more helpful to you (or others) if you used the show questions then move into the video as I was frustrated with this at one point.
I don't understand how you couldn't take the contrapositive to make answer choice B work. Contempt -/-> PJ and believing harm -/-> PJ...therefore it makes sense to work backwards as well, with the opposite being true. Could someone explain?
@Tryingmybest Ideally with PSAa questions you want to find the argument that most closely matches the principle in its stated form, not a variation of it (ie contrapositive). There may be other reasons why one shouldn't play a practical joke other than the 2 stated that we don't know. This argument is basically saying that because the sufficient condition isn't met, the necessary condition can't be true, which is a logical fallacy. Additionally, as a rule I think prescriptive conclusions can't be contraposed the way other condition reasoning can be as the reasons that you shouldn't do something may totally differ from why you should do something, as opposed to being contrapositives.
Contrapositive: Joke ---> /Significant harm or /Contempt
B validates the necessary conditions in the contrapositive argument BUT remember, when we validate the necessary condition, that says nothing about the sufficient condition.
In other words: I can say the joke won't cause significant harm and it doesn't show contempt (necessary validated), but that doesn't mean I can draw a conclusion on whether or not I should say the joke (sufficient).
It's only when we reject (negate) the necessary can we then work back and negate the sufficient condition.
I was unsure between B and C because I fell for the contrapositive trap in B. B) says that the joke isn't believed to cause harm and would not show contempt for the target. That means that the rule we are given, which requires that one of these two sufficient conditions be met, is not triggered. In other words, B) does not lead to the conclusion that the joke should not be played. But does that mean that the joke should be played? No. Aren't there other reasons why it might be wrong to play a joke? We are given 2 conditions (harm and contempt) but there could be others. That's why the conclusion in B), that it would not be wrong to play the joke, is not a reachable conclusion from the rule we're given.
@MitulChowdhury No. The only contrapositive that can be taken is:
if it is NOT the case that one should not play a practical joke -> it would not cause harm to the target, and it would not cause that person harm.
As you can see, this is not the same thing as saying that you SHOULD play the joke. And even if it did say that, it is still the succificient condition, not the necessary.
Reasoning on why B is incorrect is somewhat questionable because why are we putting = between wouldn't be wrong and would be right? Because wouldn't be wrong also could mean neutral. A gray area exists.
Subscribe to unlock everything that 7Sage has to offer.
Hold on there, stranger! You need a free account for that.
We love that you want to get going. Just create a free account below—it only takes a minute—and then you can continue!
Hold on there, stranger! You need a free account for that.
We love that you came here to read all the amazing posts from our 300,000+ members. They all have accounts too! Just create a free account below—it only takes a minute—and then you’re free to discuss anything!
Hold on there, stranger! You need a free account for that.
We love that you want to give us feedback! Just create a free account below—it only takes a minute—and then you’re free to vote on this!
Hold on there, you need to slow down.
We love that you want post in our discussion forum! Just come back in a bit to post again!
Sorry, you need a subscription for that.
Happens all the time: now that you've had a taste of the lessons, you just can't stop -- and you don't have to! Click the button.
96 comments
Why cant an answer choice follow the contrapositive of the rule?
Can we never negate rules? It can never be "/Should not PJ" and that would then become "Should PJ" so we would know what that is? Or is that for any formal logic but rules?
@DakshMalik I also was confused with this at first, but I think he's saying that "Should play joke" can never be a necessary condition. If we were to negate the conclusion, "/Should PJ" (should not PJ), then "Should PJ" would become a sufficient condition, and not a conclusion.
How do we know if its PSAa or PSAr based off the question stem? They seem the same to me
@jennawiese I think the only difference is the stimulus and the a/c.
I eliminated A because it refers to harming "someone" which doesn't necessarily mean it's talking about the target of the joke.
This is a common pattern in wrong answers which I sometimes glaze over: "Should have realized" vs. "believed"
Other examples:
"occurred" vs. "believed"
First, you said that since this is a conjunction ("Or"), if either condition is triggered, we can conclude that the jokes "should not have played." When you evaluated answer A, you said "even if it was not contemptuous" is useless and pointed to the diagram you made. Why should "not contemptuous" have been useless? Yes, it doesn't meet our condition, but until there, the answer is actually fine. Since we needed either condition, it is fine that the joke was "not contemptuous." The answer messes up on the second condition. Could you please clarify why you struck the "even if it was not contemptuous" line?
I was also choosing between B and C and the MAIN reason I baked away from C was b/c it said "show contempt to ANYONE" guys...the principle said "that person" though... the person the joke is being played on. So wouldn't that be wrong?! helppp
@mahi0615 C is still correct because if the joke doesn't show contempt for "anyone" than we can assume it doesn't show contempt for that one person, because it shows contempt for no one! Therefore, that piece of the application fits the stimulus. (Note: this is different from D listing "someone" is shown contempt because we cannot assume that this is or isn't the "someone" that the joke is being played on).
B has an unreachable conclusion in that not fulfilling the "contempt" or "harm" conditions does not guarantee that the prank should be played.
Hope this helps!
Love the little aside on the prescriptive "should". From my perspective, it's useful to think about should vs ought. Should, strictly understood, is subjective guidance defeasible for a good reason. Ought, strictly understood, is an objective authority giving a moral imperative (that can only be defeated with a superior moral imperative). But they overlap. Especially in modern usage, should can be used to mean ought. If should is being used in a principle, it could mean guidance (you should bring an umbrella), or it could mean it's a moral imperative (you shouldn't hit people), and you're going to have to look elsewhere for the clues as to which one is meant.
Can you not do contrapositive with De Morgan's Law?
@JesseMcCarthy You can take the contrapositive which would be " should play joke -> /contempt and /believe it would cause harm " but that would not allow us to conclude that a joke should be played because the "should be" condition is sufficient and on the left side of the arrow.
Arguement =
shows contempt or believes harm --> /play practical joke
basically if shows c or believes h than do not play practical joke
contrapositive =
if play practical joke --> /show contempt and /believe harm
basically if you play practical joke then we know it does not show contempt and one does not believe harm.
AC B. is wrong because the original argument and the contrapositive DOES NOT assert when it would be wrong for one to play a joke. We just know what makes one not be able to play a practical joke and if one does do it what it should not have. AC. B. states it would not be wrong for me to play it but we do not know when it would be wrong.
can you not create a contrapositive?
I get why C is the "most" correct but why would it be enough if it only covers one condition? and not the other -showing contempt- condition
@MelanieGonzalez The stim says "or."
@MelanieGonzalez since it says or only one could be sufficient for it to be triggered
woah this one was kind of hard. but once i went back and realized it said "to that person" and not "to anyone/someone" all the other answer choices fell apart.
Although I got it right, I'm curious when do we know a conclusion is unreachable? If it because this is an "or" statement? Why doesn't the contrapositive work in this circumstance?
@rjon27 update: i found the answer from a tutor on the discussion board for the question itself. Basically, still take the contrapositive but make sure to note if an answer choice is confirming the sufficient conditions (left side of the arrow) or the necessary conditions (right side of the arrow). B says that the necessary conditions are met but that doesn't mean the joke can be played. Hope this helps!
Tutor Answer:
Contrapositives are ALWAYS valid to use in answering any type of question. For this question, you started with a correct diagram of the stimulus:
Shows contempt OR believes it will bring significant harm -> /ok to play practical joke
The contrapositive of this is:
ok to play practical joke -> /show contempt AND /believe it will bring significant harm
Answer choice B shows the necessary conditions are satisfied. But if the necessary conditions for X are satisfied, that DOES NOT mean we can infer X. This is what 7Sage calls the "oldest trick in the book"—confusing necessary and sufficient conditions. You can read more about this common mistake here in our Argument Flaw Cheat Sheet: https://7sage.com/lessons/logical-reasoning/flaw-or-descriptive-weakening-questions/argument-flaw-cheat-sheet
Is there an earlier lesson that talks about prescription-to-judgment inferences?
we got em with this one ah question
Or you can apply the Jackass Negation: One should always play a practical joke on someone, especially if it shows contempt and/or could bring significant harm to that person. ;)
For B to be correct it would have to have the following structure: Since it would not be wrong for me to play the practical joke, it must be that the joke would show no contempt for the person it is played on and that I have no reason to think it would bring significant harm to anyone.
please stop hiding parts of the answer choices, i get you are trying to help but its messing with my brain.
@legallyhaya it may be more helpful to you (or others) if you used the show questions then move into the video as I was frustrated with this at one point.
We need a grammar lesson with this term "Prescriptive Conclusion" he keeps using in alot of videos. That would really help us.
I don't understand how you couldn't take the contrapositive to make answer choice B work. Contempt -/-> PJ and believing harm -/-> PJ...therefore it makes sense to work backwards as well, with the opposite being true. Could someone explain?
@Tryingmybest Ideally with PSAa questions you want to find the argument that most closely matches the principle in its stated form, not a variation of it (ie contrapositive). There may be other reasons why one shouldn't play a practical joke other than the 2 stated that we don't know. This argument is basically saying that because the sufficient condition isn't met, the necessary condition can't be true, which is a logical fallacy. Additionally, as a rule I think prescriptive conclusions can't be contraposed the way other condition reasoning can be as the reasons that you shouldn't do something may totally differ from why you should do something, as opposed to being contrapositives.
@Tryingmybest Another way to look at B is:
Significant harm and Contempt ---> /Joke
Contrapositive: Joke ---> /Significant harm or /Contempt
B validates the necessary conditions in the contrapositive argument BUT remember, when we validate the necessary condition, that says nothing about the sufficient condition.
In other words: I can say the joke won't cause significant harm and it doesn't show contempt (necessary validated), but that doesn't mean I can draw a conclusion on whether or not I should say the joke (sufficient).
It's only when we reject (negate) the necessary can we then work back and negate the sufficient condition.
what exactly does prescriptive language mean?
@SoniaKulkarni whether or not one *should do something. A descriptive statement is "its wrong to do x"
prescription, "one should not do x"
I was unsure between B and C because I fell for the contrapositive trap in B. B) says that the joke isn't believed to cause harm and would not show contempt for the target. That means that the rule we are given, which requires that one of these two sufficient conditions be met, is not triggered. In other words, B) does not lead to the conclusion that the joke should not be played. But does that mean that the joke should be played? No. Aren't there other reasons why it might be wrong to play a joke? We are given 2 conditions (harm and contempt) but there could be others. That's why the conclusion in B), that it would not be wrong to play the joke, is not a reachable conclusion from the rule we're given.
isn't B a contrapositive of the Rule in the question?
@MitulChowdhury No. The only contrapositive that can be taken is:
if it is NOT the case that one should not play a practical joke -> it would not cause harm to the target, and it would not cause that person harm.
As you can see, this is not the same thing as saying that you SHOULD play the joke. And even if it did say that, it is still the succificient condition, not the necessary.
Little key I made for myself:
PSA (LR Q#8) All Types: Prescriptive vs. Morally Descriptive Language
When/ When not to conflate the two is very tricky!
Often, wrong answer choices will use morally descriptive language in place of prescriptive
Seems correct, but is actually a trap answer
When to translate prescriptive to morally descriptive:
When stimulus makes prescriptions based on moral judgements
Ex. Do not prank disabled individuals
Here, answers that are morally descriptive could be correct
When NOT to translate prescriptive to morally descriptive:
When stimulus has nothing to do with morality at all
Ex. Do not forget to brush your teeth
Here, answers that are morally descriptive COULD NOT be correct
Brushing/not brushing arouses no moral judgements
Reasoning on why B is incorrect is somewhat questionable because why are we putting = between wouldn't be wrong and would be right? Because wouldn't be wrong also could mean neutral. A gray area exists.