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Course: LSAT > Unit 1
Lesson 7: Logical Reasoning – Video lessons- Identify the conclusion | Video lesson
- Identify an entailment | Video lesson
- Strongly supported inferences | Video lesson
- Disputes | Video lesson
- Identify the technique | Video lesson
- Identify the role | Video lesson
- Identify the principle | Video lesson
- Match the structure | Video lesson
- Match principles | Video lesson
- Identify a flaw | Video lesson
- Match flaws | Video lesson
- Necessary assumptions | Video lesson
- Sufficient assumptions | Video lesson
- Strengthen | Video lesson
- Weaken | Video lesson
- Helpful to know | Video lesson
- Explain | Video lesson
- Resolve a conflict | Video lesson
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Match the structure | Video lesson
Watch a demonstration of one way to approach a question that asks you to identify a choice that has the same argument structure as the passage on the Logical Reasoning section of the LSAT.
Want to join the conversation?
- Isn't the conclusion of choice D too severe to parallel the stimulus? (i.e. "inaccurate" vs. "incorrect")(1 vote)
- Whether the claim is inaccurate or incorrect isn't super relevant to the structure. Since either word denies the accuracy of the statement, they parallel each other in structure.(2 votes)
- at 3minutes 18 seconds she says 6 arguments there are only 5(0 votes)
- she's counting the original argument in the question as one(3 votes)
- This makes sense, however because the LSAT Flex is done on 100 percent on the computer how can we draw out the symbols?(0 votes)
- You could draw out the equation on your sheet of paper, just don't use up so much paper that you don't have enough left over for the AR section.(2 votes)
Video transcript
- [Instructor] This question asks us, the argument is most parallel
in its logical structure to which one of the following? That means we're dealing with a match the structure question. We'll be presented with one
argument in the stimulus and then the answer will be an argument that gets to the same kind of conclusion and uses the same kind
of evidence to get there. Notice that I say, kind
of conclusion evidence. That's because the actual
topic doesn't matter when you're matching structures. So go ahead and pause your
video now if you want to try to question yourself
before I explain it or let's move directly to the explanation if you don't want to
try it yourself first. It often helps for match
the structure questions if you break the argument down into its conclusion and support. As we read the stimulus, I want you to try to locate
what the arguers opinion is and identify why the arguer
believes it to be true. The passage reads, it is inaccurate to say that
a diet high in refined sugar can not cause adult-onset diabetes, since a diet high in refined sugar can make a person overweight, and being overweight
can predispose a person to adult-onset diabetes. So this stimulus is
basically one long sentence. And which part of it is our conclusion? It looks like we have a strong
signal word for evidence here with the word since. So this part after the word since, is going to be our evidence
and that leaves the first part for our conclusion. I like to bracket the conclusions that really stands out to us. It is inaccurate to say that
a diet high in refined sugar can not 'cause adult-onset diabetes. Now we ask ourselves why. Why does the arguer
believe that a diet high in refined sugar can't
'cause adult-onset diabetes? Well it's because a diet
high in refined sugar can make a person overweight and being overweight
can predispose a person to adult-onset diabetes. So I see a few terms that
repeat in the stimulus which means that we could
break this down symbolically. If we call a diet high
in refined sugar, x, and we can adult-onset diabetes, z, then this is what our argument looks like. Our conclusion is that it's wrong to say that x can't 'cause z because, and here's our evidence, x can 'cause y, which can 'cause z. If you don't like to
think of it symbolically you can describe the structure as, the arguer says that it's
wrong to say if something can't 'cause another thing because it's possible that
there's an intermediate thing that connects them both. So now we can just find the argument that matches the structure
without worrying at all about the topic. These questions can
potentially be time-consuming on test day because you're looking at six arguments in total. So one thing we can do is to
eliminate any of the choices that don't have the
same kind of conclusion that the passage has. So maybe we can get rid of some choices without having to actually
read the entire choice. Let's take a look. A, it is inaccurate to
say that being in cold air can cause a person to catch a cold. Well we can stop right here. This would match if it said
that it's inaccurate to say that being in cold air
can't cause a person to catch a cold, but this choice says that it's inaccurate to say that causation can happen. So we can eliminate this
one right off the bat. For the record though, the evidence doesn't match either. The choice ends with, since colds are caused by viruses, and viruses flourish in
warm, crowded places. There are way more than
three terms in this choice. The evidence adds viruses
and warm and crowded places. So it's just not a match but we could have stopped at
the conclusion on test day. B, it is accurate to say. Nope, nope, stop right there. It is accurate to say, is
a confirmation of a belief. But the passage denies a belief. A structure is different so
we can rule this choice out. For the record though, the choice in its entirety leads, it is accurate to say
that no airline flies from Halifax to Washington. No airline offers a direct
flight although some airlines have flights from Halifax to Boston, and others have flights
from Boston to Washington. Once again we have way too many terms happening in this choice. And we only had three
terms in our relationship from the passage. C, it is correct to say. Nope, this is the same
problem that choice b showed. This choice confirms
something, it doesn't deny it. The whole choice reads, it is correct to say that
over-fertilization is the primary cause of lawn disease, since fertilizer causes
lawn grass to grow rapidly and rapidly growing grass had
little resistance to disease. So this doesn't work. It confirms that something is
the cause of something else, and not only that it's the
cause of something else, but it's the primary
cause of something else. We want a choice that rejects statement, that denies causation. D, it is incorrect to say
that inferior motor oil can not cause a car to
get poor gasoline mileage since inferior motor oil can cause engine valve deterioration and engine valve deterioration can lead to poor gasoline mileage. This is a match. The conclusion is the same
kind as the passages conclusion and the evidence type matches too. If we map this out symbolically we can call poorer gasoline mileage z. We can call inferior motor oil x. And we can write it out like this. It's wrong to say that x can't cause z since x can cause y and y can lead to z. If you prefer to think
of it non-symbolically the arguer is disagreeing
with anyone who says that, inferior poor motor oil can't cause poor gas mileage because there's an intermediate cause of engine valve deterioration
that connects both of them. That is what's happening
in the passage as well. For completion sake
let's take a peek at E. It says that it's inaccurate
to say that Alexander the Great was a student of Plato. Alexander was a student of Aristotle and Aristotle was a student of Plato. This doesn't match. There's no hint of causation
anywhere in the argument so it's not parallel in
its logical structure to the passage. So to recap, even though the topics and
the choices will usually be different than the topic, in a match the structure has it, it doesn't matter. Your job is to find the
argument, the reason, in a way that's similar to
how the passage reasons. And a good way to do that is
to break down the argument into its conclusion and support. And then eliminate a choice
as soon as one of the pieces doesn't match it's corresponding
piece in the package. And for the record, don't worry about the order of things. For example, let's say that the stimulus has a conclusion at the end. It's very possible that the
answer has the conclusion at the beginning. You're not trying to
match style of writing, you're trying to match logical structure. Remember, this same kind of conclusion and the same kind of evidence
means that it's your answer.