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
The author mentions the
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
-
Acontrast our capacity to Remaining source text redacted.
Why choice A is not credited
Incorrect. (Lines 29-30) Mental constructs aren't the same as imagining objects. -
Bemphasize that it is Remaining source text redacted.
Why choice B is not credited
Incorrect. This answer is too extreme. While mirrors are designed to make a flat surface appear to have depth, there's no indication that it's "impossible" to look at a mirror and accept the reality of the 2D image it presents. -
Cclarify the idea that Remaining source text redacted.
Why choice C matches the stem
Correct. Question Type:
Argument Structure
Strategy Overview:
Head back to the statement in question and read it in context, then define its role within the paragraph and passage as a whole
Answer Anticipation/Relevant Lines:
Lines 39-40 are at the end of Paragraph 3, and the role of that paragraph overall was to highlight why the front-to-back explanation is so appealing.
Looking at the line in question, we can see that the sentence kicks off by saying, "Note, for example," so the statement is an example of the concept that precedes it. That statement says that mirrors make 2D surfaces appear to have depth, and this is "an exception" to the normal equation between our mental constructs and primary sense perceptions.
So let's find an answer stating that the fact in question is an example of how mirrors trick us into thinking 2D objects have depth, which is a split from the normal relationship between our mental constructs and vision.
Answer Explanation:
(Lines 37-38) Making a 2D image appear to have depth is making it appear three-dimensional. And the fact in question exemplifies that. Examples do clarify, so this is the correct answer.
Key Takeaway:
Examples tend to show up in questions! When tackling an Argument Structure question asking about an example, figure out what it's an example of, and find the answer reflecting that. Also, prioritize answers that say the example is meant to "illustrate" or "clarify," or another word that highlights the general purpose of examples. -
Dillustrate the fact that Remaining source text redacted.
Why choice D is not credited
Incorrect. (Lines 28-34) The passage notes that we are used to dealing primarily with those mental constructs, and that they're usually the same as our primary sense perception, but mirrors are an exception. The fact in question isn't meant to highlight what we normally do but rather what makes mirrors an exception to that. -
Eemphasize the degree to Remaining source text redacted.
Why choice E is not credited
Incorrect. (Lines 37-41) There are too many shifts in this answer. First, it's arguable whether making something appear to have depth modifies the shape of the object—a chair would still be in the shape of a chair! Second, "psychological activity" isn't necessarily the same as creating mental constructs. And in any case, there's no discussion of "degree" here.
What this tests
Discussion
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Explanation please 4 replies
Started by hannahnaylor5
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E vs. C 1 reply
Started by tomgbean
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Started by Ryan-Mahabir