PrepTest 140
[lcid:3659] Prep Test 140 LSAT — Reading Comp — S4
Reading comp
Passage
Questions 20-27 . Physicists are often asked why the image of an . object, such as a chair, appears reversed
Remaining source text redacted.
Passage walkthrough
Passage SummaryTopic: Science
Paragraph 1
While the appeal of the "front-to-back" theory of how mirrors work is understandable, it ultimately fails because a correct explanation needs to include both the mirror and the person looking into it.
Key Lines:
Lines 1-4 - The question/phenomenon is brought up
Lines 4-7 - A first explanation is presented
Lines 14-16 - A second explanation is presented
Lines 21-23 - The Author points out a flaw in the second explanation
Lines 26-27 - The Author explores the appeal of the second explanation
Lines 42-44 - The Author explores another reason for the appeal of the second explanation
Lines 48-51 - The Author states her conclusion about what a proper theory of mirrors must do
Meta-Structure:
Phenomenon/Explanation (or Question/Answer, which is very similar) - Here, the phenomenon is the "reversed" image in mirrors, the question, why does that happen? One explanation is that it reverses around the human field-of-sight axis. Another is that it reverses things front-to-back, but the Author says this is "based on a false premise" (Lines 22-23). Finally, the Author concludes that a proper explanation needs to take both the observer and what mirrors do into account.
Last Thoughts:
First, this is a notoriously difficult passage, so if you struggled, you're in good company! When that happens, rely on the structure and statements of opinion. Those two things will help you get through the difficult passages.
The first paragraph is a little confusing, so we should expect some questions on that—we'll need to head back to figure out what the correct answer is for any questions dealing with the concept of field of sight axes and rotation.
One thing that's absolutely important to think about—the Author's closing statement, where we finally learn her opinion on the subject of explaining mirrors. While two theories are presented, the Author concludes not with the acceptance of one theory over the other, but rather with the adoption of a criterion by which theories should be judged. She concludes that a theory is valid "only if we consider both what mirrors do and what happens when we look into mirrors" (Lines 49-51).
How does this apply to the two theories? We know that she pointed out an appeal of the second theory (the Reverse Image theory) is that it cuts out the observer, so she believes that theory isn't a good one (which lines up with her stating it relies on a false premise). The first theory does rely on the observer to explain how a mirror works—it relies on human vision featuring a vertical axis, explaining the left-to-right reversal. But just because it matches up with a requirement for a valid theory doesn't mean the Author accepts it—she never explicitly does, so we have to be careful about selecting answers that are too accepting of that theory.
Paragraph 1
- Paragraph note
- A question/phenomenon is introduced, along with an answer/explanation
- Views, minor Meta-Structures, and the author's attitude
- Phenomenon - Mirrors reverse images left-to-right instead of top-to-bottom
- Explanation - "Field-of-Sight" explanation - the reversal reflects how human field of sight is rotated (vertical axis)
- Base example - Chair
- Paragraph note
- Another answer/explanations is presented, and the Author gives an opinion on it
- Views, minor Meta-Structures, and the author's attitude
- Explanation 2 - Mirrors reverse front-to-back, which makes sense if you think about the reflected chair as being inside the mirror
- Problem with Explanation 2 - Most notable: Based on false premise, since the "chair" inside the mirror isn't real
- Paragraph note
- Why Explanation 2 is appealing
- Views, minor Meta-Structures, and the author's attitude
- It makes sense with our senses, since we "see" the chair in the mirror and thus think of it as real
- Example - We don't focus on mirrors but on objects in them
- Paragraph note
- Another reason Explanation 2 is appealing, with the Author's rebuttal
- Views, minor Meta-Structures, and the author's attitude
- Scientists try to explain without referring to observer
- Author - When you're trying to explain an observation, you need the explanation to include the observer
While the appeal of the "front-to-back" theory of how mirrors work is understandable, it ultimately fails because a correct explanation needs to include both the mirror and the person looking into it.
Key Lines:
Lines 1-4 - The question/phenomenon is brought up
Lines 4-7 - A first explanation is presented
Lines 14-16 - A second explanation is presented
Lines 21-23 - The Author points out a flaw in the second explanation
Lines 26-27 - The Author explores the appeal of the second explanation
Lines 42-44 - The Author explores another reason for the appeal of the second explanation
Lines 48-51 - The Author states her conclusion about what a proper theory of mirrors must do
Meta-Structure:
Phenomenon/Explanation (or Question/Answer, which is very similar) - Here, the phenomenon is the "reversed" image in mirrors, the question, why does that happen? One explanation is that it reverses around the human field-of-sight axis. Another is that it reverses things front-to-back, but the Author says this is "based on a false premise" (Lines 22-23). Finally, the Author concludes that a proper explanation needs to take both the observer and what mirrors do into account.
Last Thoughts:
First, this is a notoriously difficult passage, so if you struggled, you're in good company! When that happens, rely on the structure and statements of opinion. Those two things will help you get through the difficult passages.
The first paragraph is a little confusing, so we should expect some questions on that—we'll need to head back to figure out what the correct answer is for any questions dealing with the concept of field of sight axes and rotation.
One thing that's absolutely important to think about—the Author's closing statement, where we finally learn her opinion on the subject of explaining mirrors. While two theories are presented, the Author concludes not with the acceptance of one theory over the other, but rather with the adoption of a criterion by which theories should be judged. She concludes that a theory is valid "only if we consider both what mirrors do and what happens when we look into mirrors" (Lines 49-51).
How does this apply to the two theories? We know that she pointed out an appeal of the second theory (the Reverse Image theory) is that it cuts out the observer, so she believes that theory isn't a good one (which lines up with her stating it relies on a false premise). The first theory does rely on the observer to explain how a mirror works—it relies on human vision featuring a vertical axis, explaining the left-to-right reversal. But just because it matches up with a requirement for a valid theory doesn't mean the Author accepts it—she never explicitly does, so we have to be careful about selecting answers that are too accepting of that theory.
Question prompt
With which one of
Remaining source text redacted.
Why the credited answer is right
Credited answer: C
The notes below walk through why it fits the stem and how to eliminate the rest.
Question Type
Science
Answer choices
-
AThe failure of one Remaining source text redacted.
Why choice A is not credited
Incorrect. First, this answer misses the mark a bit on the Author's opinion, as she believes the front-to-back theory is successful at describing what mirrors do (Line 27-28). However, optical equipment is unmentioned and is thus out of scope here. -
BExplanations of what mirrors Remaining source text redacted.
Why choice B is not credited
Incorrect. (Lines 12-13; Lines 14-16) The Author discusses only two explanations of how mirrors work, only one of which she suggests fails to be complete—it's successful (to a point) at describing what mirrors do. This doesn't support an answer about what is "generally" true of these explanations. -
COne explanation of what Remaining source text redacted.
Why choice C matches the stem
Correct. Question Type:
Must Be True
Strategy Overview:
Review the Author's overall viewpoint and any opinion statements she made
Answer Anticipation/Relevant Lines:
The question stem here is silent as to the topic of the answer, so we can't head back to any specific portion of the passage. Instead, we need to focus on the Author's overall opinion and any specific opinions she lists. The answer could be more detail-based, and we'll address that when it comes up.
Overall, the Author had three main points. First, the front-to-back theory isn't correct, or is at least incomplete, even if it's successful at explaining how mirrors work to a point. That's because, second, any complete theory has to include both the mirror and the observer. And third, the appeal of the front-to-back theory makes sense.
Let's focus on answers that align with these views, using our notes and the passage to back up any details in those answers.
Answer Explanation:
(Lines 42-45) This lines up with our anticipation because it talks about an explanation lining up with the traditional tendency, which would explain why it's appealing. The Author kicks off Paragraph 4 by stating that acceptance of the front-to-back theory is "motivated in part by the traditional desire" to split the observer from the phenomenon. This answer paraphrases that, making it the correct answer.
Key Takeaway:
For a question that asks you to find something with which the Author would agree while not suggesting a topic, focus on her overall viewpoint and any individual statements of opinion. While the correct answer could focus on facts, it's likely to at least have somewhat of an opinion stated in it. -
DThe degree to which Remaining source text redacted.
Why choice D is not credited
Incorrect. (Lines 28-34) The Author doesn't connect the mental construct/primary sense perception discussion to scientific training. -
EConsidering objects reflected in Remaining source text redacted.
Why choice E is not credited
Incorrect. (Lines 28-42) Paragraph 3 is a bit complex with its discussion of these topics, and that can make this answer tempting—if we're not 100% solid on the content, we might want to pick an answer addressing it. However, note that this answer talks about the consideration of mirror images as mental constructs here is said to interfere with our understanding of our primary perceptions. However, the understanding of our primary perceptions isn't at question in the passage—rather, our understanding of how mirrors work is. As such, this answer is incorrect.
What this tests
Discussion
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Why not D? 1 reply
Started by Augusto
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Why is C correct? Why is E incorrect? 2 replies
Started by Ryan-Mahabir
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Help 2 replies
Started by Batman