[Anonymous]

Hi again, Mike. I’ve been reviewing PT 62 in depth after I got a score of 149. I have noticed a lot of stupid mistakes that I made simply by not reading carefully enough, so I’m not freaking out (yet). It was also the first time I attempted a real exam.

There are some questions that I just can’t wrap my head around. Specifically, in LR Section 2, #8 and #16 are really bugging me.

#8: As far as this question goes, I can definitely see why A might be a correct answer, given that the conclusion uses the phrase “at any given stage.” This shows that the argument assumes that because there is a backup system at every stage that nothing bad will happen over the entire trip. I understand that it applies a fact that may be true about one part of the trip to the whole trip. But, in my mind, this could also mean that B is correct. To make things more confusing, when I first read this stimulus, the flaw that I immediately went to was that the backup system itself does not guarantee safety, and that other factors may cause this backup system to malfunction, so I thought the answer would be D. While I can understand the final answer, my concern is that if I see a similar question in the future, that I may easily misinterpret the flaw (and find other flaws), which would lead me to the “wrong” answer. As the instructions mention in each section, there may be more than one “correct” answer, but one of these is the “best.” It ultimately comes down to the correct version of reasoning analysis. (How frustrating…)

#16: For this question, I understand that the conclusion/argument is that snoring can damage the throat. The evidence is that patients underwent throat surgeries and it was shown that those who snored more frequently had throat abnormalities. In my mind, what would strengthen this argument is something that shows for sure that throat abnormalities are linked to snoring or vice versa. Meaning, there is nothing else besides snoring that could have caused the throat abnormalities or that the throat abnormalities could have only come about because of snoring and nothing else. But the correct answer seems to be the exact opposite of my train of thought. This is plain old confusing.

For reference, I have gotten up to Chapter 10 in the Trainer. I felt very confident in my ability to see flaws before taking the Prep Test, but every time I see actual test questions, I get overwhelmed and have trouble filtering out unnecessary facts.

[LSAT Dan]

Question number 8 really illustrates the importance of identifying the conclusion and focusing on it on LR questions. On this question, the conclusion is that it exaggerates the risk to say explorers are unlikely to survive the trip. Which is another way of saying that they’re likely to survive the trip.

The evidence for this is that they’re likely to survive each individual stage (last sentence), which in turn is supported by the information about the backup system.

And that’s the groundwork for (A), the part-to-whole fallacy. Let’s break down the general terms of (A) and see how they match up to the specific terms in the passage: The problem is that the argument infers (concludes) that something (it is safe) is true of a whole (the trip) merely from the fact that it is true of each of the parts (stages).

The evidence is about the stages; they’re safe. But the trip is composed of multiple stages on a long trip. A single stage is not a trip (or as Mike would say, a piece is not a puzzle). It only takes one stage to go wrong to kill everyone. Analogously, let’s say you’re at a blackjack table, and a crazy guy pulls a gun on you. He says, “If the next card off the top of the deck is the 2 of diamonds, I’m going to kill you; otherwise I’ll leave.” For the sake of this analogy, let’s say you believe him. ok, you’d probably be terrified, but some small part of your brain would be telling the rest of you that you should feel pretty safe; a deck of cards has 52 options, so there’s a better than 98% change that you’re going to be fine. That’s a stage – drawing one card.

Now let’s say he says, “I’m going to pull a card off the top of the deck, and we’re going to do it again 20 more times, and if any of the cards is the 2 of diamonds, you’re dead.” Now you’re feeling not quite so safe. If a nonzero amount of danger occurs repeatedly, at some point, the whole operation is in serious jeopardy, even if the individual risks are small.

So what’s wrong with the other answers that tempted you? Let’s start with (B). “Infers” is synonymous with “concludes.” (B) misstates the passage – the passage doesn’t conclude that something (a fatal accident) CANNOT happen; it concludes that it’s an exaggeration to say that it probably will happen. The passage writer is saying it’s *unlikely*, not *impossible*. That may strike you as a subtle distinction, but those sorts of fine distinctions and language parsing are actually some of the only ways in which the LSAT bears any resemblance to law school. And the difference IS clear, if you look for it – (B) is too strong for what the passage actually concludes.

(D) is similar; it’s too strong. The passage writer doesn’t suggest that the backup system is CERTAIN TO (“will”) work; instead, the assertion is that the system makes a fatal catastrophe “quite unlikely.”

But if you identify and focus on the conclusion, you should be looking for an answer choice like (A). What is the conclusion about? The trip – it’s safe. What is the evidence about? The stages – they’re safe. As always (on flaw questions), there’s a mismatch between the premises and the conclusion. In this case, it’s the part to whole fallacy – taking evidence about the part, and drawing a conclusion about the whole.

#16 illustrates something that more commonly shows up on flaw questions, but you should always been looking for it, because it’s extremely common in the LR section. The premises give us a correlation, but the conclusion asserts cause and effect. Notice that saying that snoring “can damage the throat” is clear cause/effect language – the snoring is the cause, and the throat abnormalities are the effect. But the premises don’t tell you that’s the case. Don’t just identify the conclusion; find its contrast with the premises. Correlation does not equal causation.

Anytime a passage on the LSAT gives you a conclusion that A causes B, you should *immediately* think of the two most common alternatives – maybe they got it backward, that is, maybe B caused A. Or maybe A and B are both effects, and something else is the cause. In other words, maybe C caused A and B. So here, we have:

S –> TA (snoring causes throat abnormalities). From my preceding paragraph, you should immediately think “Maybe they got it backward; maybe the throat abnormalities cause people to snore.” (E) says that’s not the case – it does what commonly happens in strengthen questions; it eliminates a possible alternate explanation. And when you eliminate a possible alternate explanation, you strengthen the argument for the actual explanation.

Here’s another way of looking at it. Let’s say you’re a scientist, and you notice this correlation between throat abnormalities and snoring. You think that snoring causes the throat abnormalities (like the passage says), but you’re not sure. You’d say it’s:

60% snoring causes throat abnormalities
30% throat abnormalities cause snoring
10% something else.

You conclude that snoring causes throat abnormalities, but you’re not SURE. Then one of your other scientist friends comes along and says, “Hey, I’ve just proven that the throat abnormalities don’t cause snorting” (answer choice (E)). Now you have to reassess your estimate. That 30% is no longer possible, so it gets distributed between the other possibilities. Now, maybe it’s:

85% snoring causes throat abnormalities
15% something else
0% throat abnormalities cause snorting (if (E) is true)

Your conclusion just got stronger – it went from 60% to 85%. ANYTIME a possible alternate explanation is eliminated, the conclusion in the passage (or the argument in the passage, if you prefer) gets stronger. When the conclusion is “A causes B,” the passage is suggesting two possible alternatives for you to consider: Maybe B causes A, and maybe C causes both A & B. Most of the time, on this type of argument, the right answer will revolve around one of those possibilities.

Hope this helps.

Go Bruins!

[Anonymous]

Thank you so much, Dan! Your explanations really help my understanding of the questions. I didn’t realize that it may be easier sometimes to simply eliminate answer choices as you did for #8, based on the mere fact that “will work” was never truly confirmed in the stimulus, etc. It makes it clear that the point of the argument was never to prove that the backup system would work or not. #16 is also very clear now; simply taking the points and correlating/negating makes it so much easier. I think a lot of times, I try to read the answer choices before working out the question for myself, and it ends up confusing me.

While I’m at it, #17 in this same Prep Test seems similar to #16, but it would really help if you could provide a simplified explanation.

[LSAT Dan]

Glad you found it helpful. I’ll post in the morning about Question 17.

[LSAT Dan]

Apologies…my mother was in a car accident last night, and the fallout kept me busy this morning (and I’m on my way to UCLA to teach a class in a few minutes). If you’re on campus and want to say hi and talk briefly about that question, my class is from 3-6 in room 270 of the Powell Library (the classroom immediately to the left when you enter 270). I’ll be there a while before my class starts, and also a while after it finishes. I’ll post about Q17 later, either way; it illustrates one of my favorite practical tips for assumption questions.

[Anonymous]

Oh no! I’m sorry to hear that. I hope everything is ok now. Unfortunately, I don’t live near campus, so I won’t be able to be there today. Hopefully an explanation of the question on here will suffice. Thank you for following up.

[LSAT Dan]

Sorry for the delay! This is a sufficient assumption question, so the right answer has to get us to the conclusion. So step 1 is to identify the conclusion, which is “One should never sacrifice one’s health to sacrifice money.” If you weren’t sure that’s the conclusion, you can get there by process of elimination – “For” is a premise indicator, so the other part of the passage is a premise.

So here’s how (A) works to guarantee the conclusion (when combined with the stated premise):

There are two ways to translate (A). Your (preliminary) goal is to get rid of the “only,” to create a straight up if-then statement (this should be your goal when you have to diagram an “unless” statement, also). When translated, (A) says, “If acquiring money would make happiness unobtainable, then you should not do it.” My method of translating “only” statements differs from the way they’re usually taught; you may have translated it to “If you should obtain money, then it will not make happiness unobtainable.” That’s not wrong, logically (notice that it’s the contrapositive of my version, which means it’s logically equivalent), but it’s not the most helpful construction, because it’s the effect on happiness that’s the triggering condition, and usually, that means it will be more helpful if that’s on the left side of the arrow.

But back to the passage, with the addition of (A) (notice that when evaluating any answer choice on a sufficient assumption question, you just go ahead as assume it’s true (as the question stem says). Here’s the passage + (A):

1. If you don’t have health, you can’t have happiness. (Premise from passage)
2. If it means you can’t have happiness, you shouldn’t obtain money. (A)
3. (Conclusion) If it’s going to cost you your health, you shouldn’t obtain money.

Notice that the first two (the premises) lead you to the conclusion, which is what you’re looking for in a sufficient assumption question.

A couple of practical tips that can zero you in on (A) here. Broadly speaking, there are two types of statements – descriptive, and normative. The normative statement is essentially a moral judgment – it says that something is good or bad, or right or wrong, or in this case, that you should or should not do something. This is a very reliable tip (though not surefire) – You can’t go from descriptive premises to a moral conclusion. When you see a moral conclusion, there has to be a parallel moral premise. In other words, when the conclusion tells us that we “should not” sacrifice health to obtain money, there HAS to be a premise that tells us under what conditions you shouldn’t sacrifice health. Notice that NONE of the other answer choices give us that “should” statement, except (C). But (C) doesn’t lead to what we need it to – sacrificing health. It tells us about how health should be “valued,” which doesn’t tie into the argument at all. On general principles here, without diagramming or wrapping your head around the argument, (A) is really the only answer that *could*’be right.

Here’s another shortcut to (A). Again, not surefire, but pretty reliable, especially when he passage is short. On an assumption question, look for a key term in the conclusion (in this case, money). You can’t reach a conclusion about money unless you have a premise about money. Since we don’t have a stated premise about money, there must be an UNstated premise about money. And what’s another word for an unstated premise? An assumption.

The answer choices are the possible assumptions – now we know that we need one that includes money. What is money going to be tied to? The term that appears in a premise, but then disappears – Happiness. It’s mentioned in a premise, but then it goes away. The argument jumps from happiness (in the premise) to money (in the conclusion). The right answer will link those two, as (A) does.

But what about health? That’s the million dollar question. In a conditional logic, 2-premise argument, on an assumption question, you’re going to have two main terms. The one that appears TWICE in the passage generally isn’t going to be part of the right answer. Notice, we have reference to health in both the conclusion and the premise. That pretty much means it’s not part of the right answer, and (B), (C), and (E) can be dismissed immediately! How can I make such a blanket statement? To answer that question, we have to consider the basic structure of a simple connected premises argument, and also the basic structure of an assumption question. First, the argument:

A–>B
B–>C
Therefore A–>C

Example:
All poodles are dogs.
All dogs are mammals,
Therefore, all poodles are mammals.

Notice, each term appears twice in the completed argument. “Dogs” appears in each premise, and “poodles” and “mammals” both appear in the conclusion and in one premise. Hold that thought.

Now, let’s look at the structure of a sufficient assumption question. An assumption is just a missing premise. To make this a sufficient assumption question, we need to remove a premise. That premise then becomes the right answer. Let’s remove the second premise. So the passage now is:

All poodles are dogs. Therefore, all poodles are mammals.

Notice that the term “poodles” appears twice. Also notice, it’s not part of the right answer, which is “All dogs are mammals.” The right answer connects the two terms that only appear once – dogs and mammals. The term that appears twice isn’t part of the right answer. We can disregard it.

What if we removed the first premise, instead? Then the passage would be:

All dogs are mammals. Therefore, all poodles are mammals. Now, the right answer is “All poodles are dogs.” The term that’s not part of the right answer is different – mammals. But it’s still the only one that appears twice in the passage. It’s like magic!

So getting back to Q.17, when we see an assumption question – especially a short, sweet one like this – and it only mentions three terms – health, happiness, and money – the right answer is going to tie together the two terms that only appear once – money and happiness. And it’s going to have a “should” statement, because there’s one in the conclusion, and it didn’t come from the passage, so it must have come from the assumption. Those two things alone – which can be determined at a glance, with no diagramming – guarantee that the only answer that *possibly* be correct is (A).

Hope this helps…drop a reply if you could use clarification on any of it; I know I dropped a lot in here.

[Anonymous]

These strategies certainly make sense for this question! I can clearly see that there is a missing link in the argument, and relating money to happiness brings it all together. Hopefully I can improve with more exposure to similar questions. Thank you so much for the help!!

[LSAT Dan]

Very welcome…glad you found it helpful.