Reading comp PrepTest 144 · Section 1 · Question 20
Passage
. Passage A . Karl Popper's main contribution to the philosophy . of science concerns the power of negative evidence.
Remaining source text redacted.
Passage walkthrough
Passage SummaryTopic: Science
Passage A
Paragraph 1
Paragraph 1
Passage A - Popper's philosophy of science doesn't reflect the reality scientists face, especially with respect to the certainty with which negative evidence can disprove theories.
Passage B - When predicting the orbit of Uranus, scientists were correct in predicting a new planet, but in a similar situation with Mercury, it was actually Newton's laws that were shown to be incorrect.
Key Lines:
Passage A:
Lines 3-5 - An example makes a distinction much clearer
Lines 6-10 - A view is clarified and the Author calls it exaggerated ("hyperbolic")
Lines 17-19 - The Author criticizes the opposing view
Lines 30-32 - The Author clarifies her view, showing a shared viewpoint and an opposed viewpoint with the opposing point
Passage B:
Lines 41-44 - Alternative possibilities are discussed
Lines 48-51 - One possibility is shown to be correct
Lines 53-54 - A similar situation is raised
Lines 58-64 - A different possibility is shown to be correct in this example, with implications for the first
Meta-Structure - Relationship Between Passages:
Rebuttal (Passage A) - The Author of Passage A clearly thinks that Popper's philosophical contribution isn't 100% correct. However, she does clarify this at the end. Popper claims that positive evidence is inconclusive, but negative evidence is definitive in disproving a claim. The Author agrees that positive evidence is inconclusive (though she disagrees with Popper's view that it lacks all value), but she disagrees that negative evidence is always conclusive.
Comparisons (Passage B) - Passage B brings up two similar situations—planets are discovered, their orbits are predicted, and those predictions are wrong. However, the outcome of these situations is different. In the Uranus situation, it ended up being an auxiliary assumption (no other planets in the area) that was wrong. In the Mercury situation, it ended up being Newton's theories that were wrong.
Neutral Author (Passage B) - The Author of Passage B doesn't really take any sides or show any opinion. Rather, he focuses on presenting the details of two separate situations.
How do these passages relate? In a complicated manner! The first passage discusses an approach to scientific inquiry that revolves around positive and negative evidence. How does this apply to the two situations in Passage B? Well, in the Uranus case, the scientists used what they knew to predict an orbit, and that orbit turned out to be wrong. In other words, they made a prediction, and the evidence proved that prediction wrong—negative evidence!
In the Mercury example, they predicted an orbit that turned out to be wrong, so that's more negative evidence. They also then made a prediction that, similar to the Uranus situation, there would be another planet, but they didn't find one—also negative evidence!
(This was a lot of analysis, and we almost certainly wouldn't have walked through all of this ahead of heading to the questions. It's here to help you wrap your head around the passages!)
Also important to note is that the Author of Passage A talks about "auxiliary" assumptions, and Passage B brings these up as a possible place for a prediction made by a theory to go wrong. That overlap aligns the approach in Passage B with that of the Author over Popper.
Last Thoughts:
This comparative set is rough. It's hard to understand, abstract, and definitely outside of most people's area of expertise. So what can you do to make it easier? Rely on that example in Passage A, Paragraph 1. If we can understand what positive and negative evidence is, we should be able to muddle through the detail questions. And as for the Authors' viewpoints, Passage A has some clear statements of opinion, and Passage B lacks a particularly present author.
Passage A
Paragraph 1
- Paragraph note
- A philosopher is introduced, and his theory is explained in depth, focusing on a distinction
- Views, minor Meta-Structures, points of intersection, and the author's attitude
- Popper - Theory of negative evidence (vs positive evidence)
- Example - "All swans are white"
- Positive evidence - white swans (can't prove all are white); Popper says no value
- Negative evidence - black swan (one proves idea is wrong); Popper says disproves
- Author - Popper's view "hyperbolic"
- Popper - Negative evidence is core of science (scientific theory → makes predictions testable with negative evidence)
- Paragraph note
- The Author rebuts Popper's argument to some degree
- Views, minor Meta-Structures, points of intersection, and the author's attitude
- Author - Popper's view doesn't reflect scientific reality
- False prediction, premise of theory is wrong
- But which one? All theories have "auxiliary" premises from other theories and the real world (e.g., instruments work)
- Author - Popper is right to say positive evidence isn't conclusive; wrong to say negative evidence is
Paragraph 1
- Paragraph note
- A scientific situation is walked through
- Views, minor Meta-Structures, points of intersection, and the author's attitude
- Uranus orbit predictions were off, relied on Newton's laws, and auxiliary assumptions (including no other planets were nearby)
- Predictions wrong, so a premise must have been wrong
- Scientists tested other planets around, found that was the mistake
- Paragraph note
- A similar scientific situation is walked through
- Views, minor Meta-Structures, points of intersection, and the author's attitude
- Mercury orbit predictions were off, scientists predicted another planet (like with Uranus)
- No planet found, Einstein's new laws matched up with reality, so scientists rejected Newton's theory
Passage A - Popper's philosophy of science doesn't reflect the reality scientists face, especially with respect to the certainty with which negative evidence can disprove theories.
Passage B - When predicting the orbit of Uranus, scientists were correct in predicting a new planet, but in a similar situation with Mercury, it was actually Newton's laws that were shown to be incorrect.
Key Lines:
Passage A:
Lines 3-5 - An example makes a distinction much clearer
Lines 6-10 - A view is clarified and the Author calls it exaggerated ("hyperbolic")
Lines 17-19 - The Author criticizes the opposing view
Lines 30-32 - The Author clarifies her view, showing a shared viewpoint and an opposed viewpoint with the opposing point
Passage B:
Lines 41-44 - Alternative possibilities are discussed
Lines 48-51 - One possibility is shown to be correct
Lines 53-54 - A similar situation is raised
Lines 58-64 - A different possibility is shown to be correct in this example, with implications for the first
Meta-Structure - Relationship Between Passages:
Rebuttal (Passage A) - The Author of Passage A clearly thinks that Popper's philosophical contribution isn't 100% correct. However, she does clarify this at the end. Popper claims that positive evidence is inconclusive, but negative evidence is definitive in disproving a claim. The Author agrees that positive evidence is inconclusive (though she disagrees with Popper's view that it lacks all value), but she disagrees that negative evidence is always conclusive.
Comparisons (Passage B) - Passage B brings up two similar situations—planets are discovered, their orbits are predicted, and those predictions are wrong. However, the outcome of these situations is different. In the Uranus situation, it ended up being an auxiliary assumption (no other planets in the area) that was wrong. In the Mercury situation, it ended up being Newton's theories that were wrong.
Neutral Author (Passage B) - The Author of Passage B doesn't really take any sides or show any opinion. Rather, he focuses on presenting the details of two separate situations.
How do these passages relate? In a complicated manner! The first passage discusses an approach to scientific inquiry that revolves around positive and negative evidence. How does this apply to the two situations in Passage B? Well, in the Uranus case, the scientists used what they knew to predict an orbit, and that orbit turned out to be wrong. In other words, they made a prediction, and the evidence proved that prediction wrong—negative evidence!
In the Mercury example, they predicted an orbit that turned out to be wrong, so that's more negative evidence. They also then made a prediction that, similar to the Uranus situation, there would be another planet, but they didn't find one—also negative evidence!
(This was a lot of analysis, and we almost certainly wouldn't have walked through all of this ahead of heading to the questions. It's here to help you wrap your head around the passages!)
Also important to note is that the Author of Passage A talks about "auxiliary" assumptions, and Passage B brings these up as a possible place for a prediction made by a theory to go wrong. That overlap aligns the approach in Passage B with that of the Author over Popper.
Last Thoughts:
This comparative set is rough. It's hard to understand, abstract, and definitely outside of most people's area of expertise. So what can you do to make it easier? Rely on that example in Passage A, Paragraph 1. If we can understand what positive and negative evidence is, we should be able to muddle through the detail questions. And as for the Authors' viewpoints, Passage A has some clear statements of opinion, and Passage B lacks a particularly present author.
Question prompt
Which one of 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
-
Athe logical asymmetry of Remaining source text redacted.
Why choice A is not credited
Incorrect. (Lines 6-7) Passage A establishes that there's an asymmetry between positive and negative evidence, even if the Author thinks Popper applies it hyperbolically. Passage B, however, doesn't talk about these two types of evidence being asymmetric. In fact, it highlights situations where both types of evidence are relied on (e.g., Einstein's predictions matching reality is positive evidence; the predicted orbit of Uranus not matching reality is negative evidence). This answer is wrong in talking about logical asymmetry, which is absent from Passage B. -
Bthe role of auxiliary Remaining source text redacted.
Why choice B is not credited
Incorrect. (Lines 23-24; Line 44) Both passages discuss auxiliary assumptions, but only Passage B discusses planetary orbits, so this answer isn't a central concern of Passage A. -
Cthe role of negative Remaining source text redacted.
Why choice C matches the stem
Correct. Question Type:
Main Point
Strategy Overview:
Review the main points as we outlined them for both passages, then find an answer reflecting that as a central topic
Answer Anticipation/Relevant Lines:
Passage A was focused on the Author exploring Popper's philosophy of science (Paragraph 1) and refuting it at least in part (Line 7; Lines 17-19; Lines 28-32). From this, we said her main point is:
Popper's philosophy of science doesn't reflect the reality scientists face, especially with respect to the certainty with which negative evidence can disprove theories.
Passage B had a neutral author that didn't hop in to comment on what was going on. Rather, he focused on describing two situations where scientists made wrong predictions, and what the follow-up on those were. From this, we had a much more neutral main point:
When predicting the orbit of Uranus, scientists were correct in predicting a new planet, but in a similar situation with Mercury, it was actually Newton's laws that were shown to be incorrect.
There's not a lot of overlap there! However, there is some overlap. It's not in the topic being discussed, as Passage A has nothing to do with planets. However, they do overlap in discussing predictions and how evidence backs it up or not. Passage A talked about positive and negative evidence, and Passage B highlights some examples of predictions being made and evidence being found to disprove or back it up. So let's find an answer talking about these types of evidence.
Answer Explanation:
(Lines 1-2; Lines 31-32; Lines 40-41; Lines 53-54) Passage A is explicit in talking about the role of negative (and positive) evidence in scientific research. Passage B doesn't explicitly call it negative evidence, but in both situations discussed, the Author highlights a prediction made and evidence showing the prediction to be false—negative evidence. Since this type of negative evidence is highlighted as a catalyst to further investigation in both situations, it's a central topic of that passage. This answer is therefore correct.
Key Takeaway:
This is a bit of a weird question in that the correct answer requires us to infer a topic in Passage B—the focus on negative evidence. However, Passage A goes to great lengths to describe and define positive and negative evidence, and so the LSAT presented us with the information needed to see its inclusion in Passage B. -
Dthe proper technique for Remaining source text redacted.
Why choice D is not credited
Incorrect. (Lines 30-32; Lines 62-64) Both passages don't express the certainty displayed in this answer's use of the word "confirming." Passage A says that positive evidence is never conclusive, and negative evidence rarely is. Passage B talks about "increased confidence" in a theory. Neither talks about confirmation. -
Ethe irrelevance of experimentation Remaining source text redacted.
Why choice E is not credited
Incorrect. This answer is way too extreme in saying that experimentation is irrelevant in disproving scientific theories. There's nothing in either passage that would back up experiments as being useless in this regard.
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C 1 reply
Started by tomgbean