Diagramming conditional statements with subscript

[ipguyva]

Hi,

I have a question about this same problem, so I thought I would post it here. The premise in the stimulus refers to the drivers (sub-D) as those with (1) a large number of demerit points and (2) who have been convicted of a serious driving-related offense. However, the last sentence in the stimulus only refers to the drivers as those with demerit points. Why is the conditional relationship representing the last sentence as ~R_D still valid?

I actually have the same exact question. It would appear that the group of drivers who've accumulated a large number of demerit points and been convicted of a serious driving-related offense would be different from the group of drivers who have only accumulated a large number of demerit points.

The stimulus, in the second sentence, refers to the same group of drivers as in the first sentence, which is clear because of the phrase "such drivers." The third sentence does not necessarily refer to the first group of drivers, and instead appears to call out a second group of drivers having a large number of demerit points, yet silent as to whether they have been convicted of a serious driving-related offense.

Is the second group of drivers considered a superset of the first group of drivers? If so, it would explain.

[Jon Denning]

Hey est15 and ipguyva,

Thanks for the questions! We've actually got two follow ups--one from both of you--so why don't I address them individually with two posts and you guys can consider each other's for some further insight (I hope!).

est15 - that's a good question you raise, which to me is in a way about the idea of groups and sub-groups (or at least might make sense discussed in those terms). That is, if we refer to all drivers with demerit points, then we by default are also referring to drivers with demerit points who ALSO have been convicted of an offense. So when the last sentence gives us something about drivers with points (can't make them more responsible), that applies to drivers with points and offenses too.

It would be like if I was telling you about my brown dog who is male, and then you told me something about just all brown dogs ("they're not well behaved"). That would certainly apply to my male brown dog, because it applies to the group as a whole, of which males would be a part.

So back to the drivers. Essentially you get a chain, where the drivers discussed tells you jail or re-education, but then re-education is taken out because it depends on them becoming more responsible, which we're told they won't. That's a rough summary, but hopefully makes sense. That means the drivers in question (points and offense) should be sent to jail. Other drivers (no points or no offense or both) we can't know about.

Okay, last thing, because it's extremely important to conditionality with multiple conditions: where the 2 or more conditions occur--sufficient or necessary--completely changes the way you make inferences. Let me explain, and I think you'll see the tie-in to the points above:

1. If you have two conditions as sufficient, you must have both to conclude the necessary. That's why in this question we need to know drivers with points who also have an offense to conclude jail is the right decision. We wouldn't know that from just points, or just an offense, because the combination is our sufficient.

2. If you have two conditions that are both necessary, losing even one of them negates whatever was sufficient. We don't really encounter that here, but you will certainly see it. In this question we have two necessary pieces, but conjoined with "or," as "re-education OR jail," so we can lose re-education and still keep the relationship, so long as we have jail...which is the answer.

I hope that helps--please let me know if you still have questions!

Jon

[Jon Denning]

Hey ipguyva,

Thanks again for the question. I feel like it was probably answered by my last response, but just in case it wasn't let me expand on it a bit for you.

Certainly they could be different groups. It depends on how we're discussing them. If I say "drivers with points and offenses should be sent to jail," that's different than "drivers with points should be sent to jail." In the first, both sufficient conditions must occur before I conclude "jail." The second only has a single sufficient and single necessary, so it's more straightforward.

The reason I say "could" above is that, while they could be entirely different groups ("drivers with points and offenses" vs "drivers with just/only points"), they could also be related as group vs sub-group. "All drivers with points" includes "drivers with points and offenses," and that consideration factors into this stimulus: drivers with points won't become more responsible, so that rules out re-education for all drivers with points, including those who have both points and offenses.

Finally, that sub-group idea could also factor into a "prove" type situation. Showing "drivers with points and offenses should go to jail" does not necessarily prove that "drivers with points should go to jail." But flip it around. I can prove that "drivers with points and offenses should go to jail" by showing that "drivers with points should go to jail." So directionality (or fact vs conclusion, really) is hugely important, and could even come up directly in a Justify the Conclusion question: if "drivers with points and offenses should go to jail" is the conclusion I want to prove, an answer of "drivers with points should go to jail" would do it!

Hope that helps!

[Shedrickc]

I was reviewing the answer choices to make sure i understood why the answer choices were wrong. Answer Choice (D) states:) The stimulus does not address drivers who have not committed a serious driving offense, only those convicted of such an offense. I'm a bit confused since the contrapositive would indicate NOT convicted. Now, I'm just wondering if they want us to understand or use not so common sense to understand that committing a crime and being convicted of that crime or 2 very different things. Or in other words, just because you did NOT get convicted doesn't mean you did not commit the crime. Lastly, since it's a MSS question the stimulus does not have to prove the contrapositive of not convicted m3ans not committed, but convicted would strongly support not committed.

[Dave Killoran]

I was reviewing the answer choices to make sure i understood why the answer choices were wrong. Answer Choice (D) states:) The stimulus does not address drivers who have not committed a serious driving offense, only those convicted of such an offense. I'm a bit confused since the contrapositive would indicate NOT convicted. Now, I'm just wondering if they want us to understand or use not so common sense to understand that committing a crime and being convicted of that crime or 2 very different things. Or in other words, just because you did NOT get convicted doesn't mean you did not commit the crime. Lastly, since it's a MSS question the stimulus does not have to prove the contrapositive of not convicted m3ans not committed, but convicted would strongly support not committed.

Hi Shed,

Would you mind clarifying your question a little bit? With all the different posts in this thread, I'm having a hard time following exactly what you are asking, and I want to make sure I answer you as well as I can

Thanks!

[Shedrickc]

Can you eleborate on why answer choice D) is wrong?

[Dave Killoran]

Sure, here you go:

Answer choice (D): The stimulus does not address drivers who have not committed a serious driving
offense, only those convicted of such an offense.

There are also further comments on the nature of the stimulus here: lsat/viewtopic.php?f=13&t=7126. See Nikki's comment, specifically.

Thanks!

[SGD2021]

Hey est15 and ipguyva,

Thanks for the questions! We've actually got two follow ups--one from both of you--so why don't I address them individually with two posts and you guys can consider each other's for some further insight (I hope!).

est15 - that's a good question you raise, which to me is in a way about the idea of groups and sub-groups (or at least might make sense discussed in those terms). That is, if we refer to all drivers with demerit points, then we by default are also referring to drivers with demerit points who ALSO have been convicted of an offense. So when the last sentence gives us something about drivers with points (can't make them more responsible), that applies to drivers with points and offenses too.

It would be like if I was telling you about my brown dog who is male, and then you told me something about just all brown dogs ("they're not well behaved"). That would certainly apply to my male brown dog, because it applies to the group as a whole, of which males would be a part.

So back to the drivers. Essentially you get a chain, where the drivers discussed tells you jail or re-education, but then re-education is taken out because it depends on them becoming more responsible, which we're told they won't. That's a rough summary, but hopefully makes sense. That means the drivers in question (points and offense) should be sent to jail. Other drivers (no points or no offense or both) we can't know about.

Okay, last thing, because it's extremely important to conditionality with multiple conditions: where the 2 or more conditions occur--sufficient or necessary--completely changes the way you make inferences. Let me explain, and I think you'll see the tie-in to the points above:

1. If you have two conditions as sufficient, you must have both to conclude the necessary. That's why in this question we need to know drivers with points who also have an offense to conclude jail is the right decision. We wouldn't know that from just points, or just an offense, because the combination is our sufficient.

2. If you have two conditions that are both necessary, losing even one of them negates whatever was sufficient. We don't really encounter that here, but you will certainly see it. In this question we have two necessary pieces, but conjoined with "or," as "re-education OR jail," so we can lose re-education and still keep the relationship, so long as we have jail...which is the answer.

I hope that helps--please let me know if you still have questions!

Jon

Hello,

This phrase: "If you have two conditions as sufficient, you must have both to conclude the necessary" applies only in cases where there is an "AND" between the two sufficient conditions, correct? If there was an "or" we would need at least one of the sufficient conditions (meaning one is enough) to conclude the necessary?

[Adam Tyson]

Correct, SGD2021! That's an important distinction, good catch! Dave was referring specifically to a case where "and" was involved; if that had instead been an "or" it would have changed that analysis.