Reading Comprehension

PT144 · S1 · P4 · Q22 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.

22.

In passage B, which one of the following most clearly illustrates a disturbing force, as described in the middle of the second paragraph of passage A?

  1. Uranus

    Unrelated to Goal

    We're looking for Neptune. Uranus was the thing being studied, the thing being affected by the disturbing force of Neptune.

    6% picked this

  2. the sun

    Unrelated to Goal

    We're looking for Neptune. The sun didn't disturb our measurements of Uranus. (Only if you used outside knowledge could you convince yourself that the sun's mass was a disturbing force on Mercury, since Newton's theory of physics doesn't account for the way that massive objects such as the sun warp the shape of spacetime that Mercury travels through. But the passage is using the case of Mercury as an example where the THEORY was wrong, not where one of the underlying assumptions is wrong)

    5% picked this

  3. Correct

    Neptune

    Why this is right

    Scientists assumed there were no planets around Uranus when they used Newton's theory to predict Uranus' orbit. Their predictions were off because they didn't account for the disturbing force of Neptune's gravity.

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

    82% picked this

  4. Mercury

    Unrelated to Goal

    We're looking for Neptune. Mercury's orbit wasn't affected by any disturbing force; they thought maybe there was a disturbing force they named planet Vulcan, but there wasn't. The scientists' predictions were wrong because Newton's theory was off, and Einstein's was better.

    6% picked this

  5. the moon

    Unrelated to Goal

    We're looking for Neptune. The moon wasn't affecting scientists' measurements of Uranus's or Mercury's orbits.

    1% picked this

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