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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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Strengthen | Video lesson
Watch a demonstration of one way to approach a question that asks you to select a choice that would strengthen an argument on the Logical Reasoning section of the LSAT.
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- so where i'm struggling is "strengthens the argument" with Answer D. determination on a random basis is more of an observation of structure. It doesn't appear to "strengthen" the argument, but more just an outline of the methods; pointing to elements isn't a strengthener. I ,too, would still pick E. The intent of concern behind the results of increasing life span is where I see the strength backing the conclusion of the results.(2 votes)
- People who exercise also tend to make other healthier life choices (diet, sleep, etc) which would also increase one's life span. The stimulus is poorly worded on this one. It is easy to take for granted that the study was randomized as that is a common tactic in research, and it doesn't specify whether the participants were chosen from a pool of folks who already exercised as a habit, or whether they were instructed to do so during the study.(1 vote)
- Choice D in the "strengthen Video Lesson" does not agree with the stimulus. Let's say researchers picked 100 people, 30 of whom happened to exercise regularly. While researchers could have picked the 100 in random, they could NOT have picked the 30 in random because the 30 just happened to be in the population without the researchers intervention.(0 votes)
Video transcript
- [Instructor] This question asks us which one of the following, if true, most strengthens the argument? So we're looking at a strengthen question. That means that the answer will help the argument. In other words, it will
make the conclusion more likely to follow
from the given support, if we assume the answer to be true. The four wrong choices will either weaken the argument or do
nothing to the argument if we assume them to be true. Pause your video now if you'd like to try this
question on your own. Otherwise let's move
on to the explanation. Okay, let's read the stimulus. And for strengthen questions, it helps to read actively
for the conclusion and the support since the connection between those two parts is what we'll be looking to strengthen. The passage reads, a
recently completed study of several hundred subjects, all of approximately the same age, showed that those who exercised regularly during the study were much less likely
to die during the study. This indicates that exercise can actually increase one's life span. Okay, is the first sentence our support or our conclusion? It's pretty safe for us
to identify it as support since it involves a study. A study is just something that took place and gave certain results. And here, those results are that people who exercise regularly during the study were much less likely
to die during the study. Now, it's the interpretation of the study that often lends itself to subjectivity. And that's what we have
in the second sentence with the really good
signal word, indicates. The arguer is interpreting
the study's result to mean that exercise can increase one's life span. So we can mark that as our conclusion. Okay, for strengthen questions, it's usually the case that there are lots of different specific ways to strengthen the argument. And all of those ways are
completely legitimate. So a specific prediction isn't necessary or even usually recommended. Sometimes though, you might see a familiar pattern on test day, like a certain structure that you've seen a lot
of in your practice. And here we see a study. When you see a study in logical reasoning, it can be a good idea to examine the potential holes in the study. We do learn that the subjects here are approximately the
same age, so that gives us one point of fairness about the study. However, we're only given a correlation and that correlation is that the people who exercised regularly
were the same people who were the least likely to die. Then what happens is we shift to causation in the conclusion. The arguer believes that one of the correlated attributes causes the other. So it's possible that a strengthener will adjust this gap and bridge it, so that the causation is more likely to be true based on the correlation that the study shows. So to rephrase our task, we're looking for something that makes it more likely that the study is connected to real life. Great. Now that we know what
we're trying to accomplish, let's evaluate the choices. A, the subjects who did
not exercise regularly during the study tended to have diets that were more unhealthy. This information actually
weakens the argument. It's bringing up something else that could've caused the difference in death rates, like it's possible that it wasn't more exercise that helped people die less, but rather it was healthier diets. So choice A presents an alternative cause and that weakens the causal relationship that the arguer believes to exist. B, the subjects who did
not exercise regularly during the study tended to blame their lack of exercise on a lack of time. This information doesn't affect the argument at all. We aren't interested in
what the subjects blame for their lack of exercise,
we're interested in whether their lack of exercise affected their likelihood of death. It doesn't matter that the subjects claim to not have enough time. C, a large number of the deaths recorded were attributable to preexisting conditions or illnesses. This is a lot like choice A because it weakens the argument by giving a different reason that people could have
died during the study. Maybe it wasn't lack of
exercise that did it, but rather, maybe the people who didn't exercise regularly were already unhealthier than the people who did exercise regularly, for example. So this is a weakener. D, whether or not a given subject was to exercise during the study was determined by the researchers on a random basis. This is our strengthener. This choice directly
strengthens the connection of the study to the conclusion because it removes the possibility that people who didn't exercise did so for specific
health-related reasons. In other words, if the researchers randomly selected who
exercised and who didn't, then that random sampling makes the study more representative. If a choice removes a potential weakener, like this choice does,
then the overall effect is that it strengthens the argument because it takes away one possibility that would have hurt the argument, if it were true. For the record, choice E states a person who exercises regularly is probably doing so out of concern for his or her own health. And this doesn't strengthen the argument. A person's motivations
don't affect this argument because people could have very different motivations for exercising, but the fact remains that they exercise. And we need to know whether that exercise, whatever the motivation for it is, increases one's life span. So to recap, for strengthen questions, you're finding the choice
that helps the link between the evidence and the conclusion. It really helps to separate the evidence and the conclusion by seeing the evidence as information that we're given and then seeing the conclusion as an opinion that the arguer makes based on that information. Well, in a strengthen question, we want to bring the two
pieces closer together. We want to make it more likely for the conclusion to happen based on the evidence that was provided. It can also help to pretend that you're adding each
choice to the argument and seeing which way the argument moves in quality. Does it get better? Does it get worse? Does it stay the same? Look for any gaps in the argument, like where the evidence
is addressing one thing and the conclusion
addresses a different thing, and then look for a choice that helps close that gap. Or sometimes you can also
strengthen an argument by removing a potential weakener, like we did in this question. Keep a good grasp on the structure of the argument and what you're being asked to accomplish.