So in the previous lesson they said that A←s→B→C leads to a valid inference of A←s→C. This in plain English would be if some of A are B and all of B is C, then some of A are C. (For example, if some fish in the fish tank are red and all red fish are venomous then we can make the inference that some fish in the fish tank are venomous).

However, in this lesson they introduce the formal argument A←s→B←C (or in other words C→B←s→A). In this case, you would be saying that all of C is B and some of B are A. For this type of formal argument you CANNOT make an inference. When you first see this argument, you would want to make the inference A←s→C but this cannot be an inference made because it could be true but it could also be false.

Here's how that works. Imagine a circle diagram where B is a big circle and within B there is a smaller circle called C. Because the only thing that this lawgic statement tells us is that all of C is in B, the size of C can be large or small. So C could take up a big spot within B or it could be a small dot within the circle "B." However, the lawgic statement goes onto say that some of B are A. In this case, could we guarantee that at least some of C (in other words, at least one of C) will be a part of A? No. Because what if the "some of B" that is a A is a part of the circle that C does not cover? If within the circle "B," circle C and A does not overlap, it would mean that some of C is NOT A and this is a possible scenario.

For example, let's replace A with fish in the fish tank, B with red and C with venomous fish. We can make the exact same formal argument as above (A←s→B←C) by saying "all venomous fish are red and some red fish are in the fish tank." (in fish tank ←s→ red fish ← venomous) Here we can't say that some fish in the fish tank are venomous. This example argument only states that the only possible fish in the world that can be venomous are red (venomous → red). Does that mean all red fish are venomous(red → venomous)? No, that would be a mistaken reversal. The owner of the fish tank could have gotten very lucky or only picked red fish that are not venomous. In that case, are any fish in the fish tank venomous? No! Because the owner only picked the non-venomous red fish which is possible under this lawgic statement. So if the only fish in the world that are venomous are red fish and the fish tank has red fish, it does not necessarily mean that the fish tank has venomous fish.

Hope that makes sense.

#8 was a bit tricky for me. I understand why it's not reluctant rejection (author does not indicate that they want to support the critics) nor neutrality (the author bashes them in the rest of the paragraph) but "complete rejection" felt too much since the author isn't just saying "oh you are terribly wrong" but rather saying "it's actually more complex than that, so you are wrong."

I am slowly losing my ability to read apparently. Damn #27

#feedback I think there is a typo under the Phenomenon-Hypothesis passage style in the line "If the author is neutral, the main point is to present someone’s critique or to present a debate. (Look back to the Greek Dramas passage for an example of this.)" where it says "main point" instead of "primary purpose."

Don't know if anyone else thinks this, but I would appreciate most of these lecture content to stay within the earlier PTs. I would rather not use these up for drills/practices and not be able to complete the recent PTs in timed conditions. These lectures are great though, thanks for the upload! #feedback

watched the video to get some insight into greek tragedies so that I can have some background knowledge only to unlock a new fear

I feel like there are 3 assumptions that needs to be made in order to get 19 correct (as someone with no legal knowledge outside from really basic ones):

1. The only thing that the policy capturing researcher reads/considers are opinions

2. Every said opinion must be the Judge's opinion

3. The transcripts must have at least one more aspect of the case that was not included in the Judge's opinion

This was a really hard question and I am just hoping that there are no more of these questions in modern RCs.

I see your point but the way I interpreted this was that criminals by definition are those who committed the crime. Saying that those who are responsible for the crime should be defined as criminal I feel is an assumption that needs to be made. Might be wrong but that's where my head went.

It's the certainty level. When you apply the Assumption Negation Technique you would get "Some stars that are too cool to burn hydrogen are too cool to destroy lithium completely." Since the conclusion is saying that if it has lithium it must be the coolest brown stars, saying "some stars" that are too cool to burn hydrogen does not destroy lithium does not weaken the argument (because the coolest of the brown stars can still be part of the some).

Here is my interpretation of the question:

Premise:

25 years ago (gap between avg price of new car and individual income was x)

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Today (gap between avg price of new car and individual income is y)

Stimulus: x < y

In other words, the gap has increased (sorry for the math, but LR is word math so like)

Conclusion: individuals are spending larger amounts of their income buying a new car than 25 years ago

(A) - This does not affect the conclusion whatsoever if we are talking about individuals (which we are as we see in the conclusion). So what if the income of the household is now closer in amount to the price of a new car? Individual income is not and this is what the stimulus is concerned about NOT household income.

(B) - This is entirely irrelevant to the question at hand.

(C) - This kind of restates the stimulus in a way. If inflation increased both the price of new cars and income, and considering this income got much lower, then it is just saying that the gap between avg price of new car and individual income got larger. This has no effect on the argument that this increase in gap leads to the author concluding that individuals are spending larger amounts of their income. (Even if we force it, I’d say this strengthens rather than weakens)

(D) - Population is so entirely irrelevant. More people are buying new cars! Ok, but this does nothing to the argument at hand.

(E) - This weakens the argument. Let’s say a household (like (A)) buys a car and everyone chips in (in other words, it is not a sale to individuals but rather a sale to a group) about 25% of their income. This could very much mean that the amount each person chipped in could have been a smaller amount relative to their income than 25 years ago. So if this AC is true, then this provides a scenario where the conclusion is not true.

Hello,

One year late but I'd like to try and explain this.

I think you need to think of it the opposite way.

So the condition that qualifies Kay to vote for a candidate who's opinion differs from hers in at least one important topic is that:

1. There is at least one issue important to her

2, She selects one candidate for a position

3. The other candidates disagree with her on even more important issues

Sure, M agrees with Kay on the one important issue in this election and we don’t know what happens to M because the principle does not say anything about what Kay does when she agrees with someone on all important issues (like you said). But L and N do not agree with Kay on the one important issue so we can apply the principle to them. However, we can infer that L and N do not agree with Kay on more number of important issues than M. Meaning that according to the principle, Kay cannot select them in the election (peep the last sentence of the principle: “it is otherwise unacceptable to vote for that candidate”). So because L and N fail to meet the principle that underlines when it is acceptable to vote for someone when Kay disagrees with them on at least one important issues, according to the principle, Kay cannot vote for them.

I think this also makes the wording of the AC make sense. Because my initial thought was “why make the wording as “the only unacceptable course of action” instead of “the only acceptable course of action”?” (other than make it super complicated). But LSAT can’t write a correct AC like that because we can’t assert that Kay will vote for M.

Wow an excellent question to reinforce LR but this explanation left me flabbergasted. How did I miss that???

https://classic.7sage.com/discussion/#/discussion/27697/how-to-just-test-one-section-while-practicing

Look at Juliet's comment

Ah, that makes sense. Thanks!

Sorry, I think I get it now? The or WPP is because if it is effective and does not have a good legal system, it must not have been with a well paid police force since otherwise it breaks the conditional.

#help For question 2, could someone tell me how the contrapositive statement of the final conditional make sense? GLS and WPP → E can be translated as if there is no good legal system and the police are well funded, the police won't be effective. But if you take the contrapositive statement (E → GLS or WPP), wouldn't it translate to if the police is effective, they either have a good legal system or does not have a well paid police force? I also learned diagramming through another LSAT book, so if I had seen that question, I would've probably diagrammed it as E → GLS, which would translate to if police force is effective, there must be a good legal system. Is there something that this rule exception diagram do that my original diagram does not?

In a conditional, the necessary condition must occur when the sufficient condition is present. Just to simplify, let's use if A then B or C. This diagrams as A → (B or C). In this case, if A occurs, either B or C must occur. So if B does not occur, C must occur to satisfy the conditional and vice versa. So A and not B → C is counting on the fact that when A occurs, B or C must occur.

Also, I do agree with some of the other commenters that says it might not be directly applicable during the test. But I think it was really helpful in reinforcing my understanding of conditionals.

My interpretation was that there is no element in the statement which if it happened, it guaranteed that something else happened. For example, from question 9, you cannot state "permit hunting → increase in deer population" b/c that would be an extreme over generalization of the statement rather than a valid conditional.

Do you eliminate "could be true" answers in a Weaken Except question as well?

#help

Should I have known to assume that there is a causal relationship between the bats leaving the cave and there being an increased flying insects out during warmer nights? I kept (C) as a contender (since it gives an alternate explanation as to why bats might be out when its warmer: they can't fly long in the cold) but only eliminated the answer choice because I thought "they could still go out, it's just they would have to fly out more frequently to get more food." But I flagged the question because I wasn't all that convinced that (B) was the right answer in case the causal relationship was NOT implied, which meant that (B) was irrelevant to the stimulus. (Not sure if this explanation makes sense!)