Reading comp PrepTest 144 · Section 1 · Question 26

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 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 2
  • 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
Passage B
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 2
  • 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
Main Point:
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

It can be inferred Remaining source text redacted.
Why the credited answer is right

Credited answer: B

The notes below walk through why it fits the stem and how to eliminate the rest.

Question Type

Science

Answer choices

  1. A
    Popper's main contribution to Remaining source text redacted.
    Why choice A is not credited
    Incorrect. The Author of Passage B doesn't discuss Popper or the philosophy of science at all, so he wouldn't necessarily be skeptical of a claim that this was his main contribution to the philosophy of science.
  2. B
    Positive evidence plays no Remaining source text redacted.
    Why choice B matches the stem
    Correct. Question Type:
    Cannot Be True

    Strategy Overview:
    Head straight to the answers and consider each of them based on the evidence presented by Passage B's Author in support of the conclusions drawn there

    Answer Anticipation/Relevant Lines:
    First, the question type. We're looking for something that the Author of Passage B would be skeptical about—in other words, something that he would think likely isn't true. And since that would require him making a statement that in some way contradicts the one in Passage A, we can view this as a Cannot be True question, albeit one that doesn't need to be completely contradicted.

    Now to the question. This one is actually a bit nicer than it seems. It asks us to identify one of the following ideas mentioned in Passage A that the Author of Passage B would disagree with. Note that it doesn't ask us to identify whether it's mentioned in Passage A—it tells us that these ideas are mentioned there. So we don't need to check the answers against Passage A—which is nice!

    So instead we're just taking each of the answers as something Passage A said, and then seeing if we can find information in Passage B that contradicts it. With that in mind, let's head to the answer choices.

    Answer Explanation:
    (Lines 56-64) The Author of Passage B mentions that "increased confidence" resulted in Einstein's general theory of relativity when it was able to correctly predict the orbit of Mercury. That's an example of positive evidence (evidence that aligns with a prediction made by a theory) supporting a theory, so the Author of Passage B would be skeptical of this claim that positive evidence can't provide such support.

    Key Takeaway:
    Be sure that you're clear on the question stem. It would have been easy here to lose time on the exam by thinking it was asking you to find an answer that shows up in Passage A, and that some of them could be eliminated because they didn't. That's not the case here—it tells you each answer is present in Passage A, and your goal is to see which of those ideas runs counter to what is said in Passage B.
  3. C
    Auxiliary premises are usually Remaining source text redacted.
    Why choice C is not credited
    Incorrect. (Line 38; Line 61) The Author of Passage B brings up auxiliary assumptions with respect to both of the situations he describes, so there's evidence he might agree with this idea.
  4. D
    There is a logical Remaining source text redacted.
    Why choice D is not credited
    Incorrect. (Lines 56-64) In the Mercury situation, failed predictions by Newton's laws (negative evidence) was enough for scientists to reject (Line 62) those laws, but positive evidence for Einstein's theory was only enough to "increase[] confidence" (Line 63) in that theory. So, if anything, the Author of Passage B implies acceptance of the imbalance. We wouldn't say he's committed to it, but there's more evidence he agrees with it than disagrees with it.
  5. E
    Scientific research involves generating Remaining source text redacted.
    Why choice E is not credited
    Incorrect. Passage B discusses two theories and testing them, and two specific situations where they were tested. He never delves into whether a focus on refuting theories is key, and he shows an example of a theory being refuted. In short, there's really not enough information in Passage B to say how he feels about this answer, though there is some evidence he thinks that a part of science is refuting theories, so it's more in the positive than negative direction.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 5%
  2. B Credited 67%
  3. C 9%
  4. D 11%
  5. E 8%

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