Reading Comprehension

PT144 · S1 · P4 · Q21 Karl Popper

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Passage A

Passage A

The author presents and mildly critiques the ideas of Karl Popper regarding positive and negative evidence.

She starts out acknowledging the merits of his contribution. Negative evidence is definitely more powerful than positive evidence, since negative evidence has the power to prove a theory wrong, whereas positive evidence only shows that "so far, it's always been correct".

The rest of the first paragraph involves a series of attributions to Popper. Frequently, if an author is taking pains to separate someone else's ideas from her own, it's because a disagreement is around the bend. We can also see a negative attitudinal marker with the work "hyperbolic", which means exaggerating to an unrealistic degree.

Paragraph 2 delivers on our suspicions with a "However" author pivot. The second paragraph stresses that Popper goes overboard in acting like , since in the real world it's messier than that.

Testing scientific theories (to see whether we get positive or negative evidence, i.e. matching the predictions vs. not-matching the predictions) means assuming that other theories are correct, that your measuring instruments are working correctly, and potentially other assumptions.

So when negative evidence is found, it isn't immediately clear what that's telling us: it could be telling us, as Popper is thinking, that the theory we're testing is wrong but it could just be that one of our other theories is wrong, or that something went awry with the measurement.

Passage B

As we start the second passage, we're listening attentively for the first signs of Overlap. In the second sentence, we see "auxiliary assumptions" (which to me sticks out, because prior to Passage A, I had never heard the expression "auxiliary premises" before).

So we pause and possibly re-read that part of Passage A to dial in the meaning / significance of auxiliary assumptions to Passage A:

when a measurement doesn't match Theory A's predictions, - maybe Theory A is wrong - maybe an auxiliary assumption is wrong (e.g. Theory B is wrong. Idea X is wrong. Our instruments failed)

Passage B then takes us through two different examples.

Uranus Mercury

Measure U's orbit M's orbit doesn't didn't match didn't match match Newton's theory Newton's theory theory Reason for negative evidence

Aux. assump = wrong. Theory = wrong. We'd assumed there At first we thought weren't any planets aux assump of no nearby Uranus, planets near M was because we wrong, but once hadn't found Einstein's math Neptune yet worked, we found out Newt's theory was wrong.

21.

Which one of the following is mentioned in passage A and illustrated in passage B?

  1. repudiating an experimental result

    Not Mentioned in A

    Passage A never talks about objecting to an experimental result. That would be like if there were an experiment in which I recorded the color of all the swans I saw, and there were 88 white swans and 1 black swan, and you said, "I don't trust those numbers! I think he messed up. I repudiate those results."

    8% picked this

  2. revising a theory

    Not Mentioned in A

    Passage A never talks about revising any theories. It only says that when confronted with negative evidence (when a prediction fails), it's possible that the theory is wrong but it's also possible that one of the auxiliary assumptions is wrong.

    14% picked this

  3. Correct

    disproving a theory

    Why this is right

    Passage A mentions disproving theories a couple times: scientific research involves not only generating bold theories, but also searching for evidence that would disprove them. If a theory deductively entails a false prediction, then the theory must be false as well. Passage B illustrates disproving a theory with the Mercury example. The negative evidence of Mercury's orbit failing to match what Newton's theory of gravity predicted ultimately led to "the rejection of Newton's theory of gravity and to increased confidence in Einstein's theory".

    Skill tested: Locate Detail · how this choice captures the passage's function is the move to repeat next time.

    73% picked this

  4. predicting a planet's orbit

    Not Mentioned in A

    Passage A never mentions the word "planet" or "orbit".

    1% picked this

  5. theories that are not testable

    Not Illustrated by B

    The last sentence of Passage A's first paragraph sort of backhandedly allows for the possibility that some theories make predictions that aren't testable (that couldn't be disproven via evidence). Popper would not regard those as scientific theories. It's already a strain to say that "not testable theories" are mentioned in Passage A, but there definitely aren't any such theories illustrated in B.

    3% picked this

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