Reading Comprehension

PT144 · S1 · P4 · Q20 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.

20.

Which one of the following is a central topic of both passages?

  1. the logical asymmetry of positive

    Fails B: positive evidence

    This answer is a fine match for passage A, but passage B never brings up positive evidence, nor does it speak to an asymmetry between how strong positive vs. negative evidence is.

    7% picked this

  2. the role of auxiliary assumptions

    Fails A: planetary orbits

    This is a decent match for passage B, but passage A never talked about "planetary orbits".

    4% picked this

  3. Correct

    the role of negative evidence

    Why this is right

    Our prephrase for passage A was something like, "it's mainly concerned with what negative evidence does / doesn't tell us about the underlying theory". And passage B discussed examples in which negative evidence either showed that an auxiliary assumption was wrong or showed that the underlying theory was wrong (initial measurements of Uranus's orbit and of Mercury's orbit were each negative evidence for Newton's theory). Both passages are letting us know that negative evidence plays this mixed role in scientific research: sometimes it shows us that one of our auxiliary assumptions is wrong / sometimes it shows us that the underlying theory is wrong.

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

    67% picked this

  4. the proper technique for confirming

    Fails Both

    Neither passage speaks about the "proper" way to confirm a scientific theory. For example, according to passage A, what is the proper technique for confirming a scientific theory? [crickets] Is the proper technique killing all the black swans so that you never have negative evidence? We don't have any roadmap from passage A about how we should confirm a theory. Passage A's focus is about the supposed strength of negative evidence (which is the opposite of confirming a theory) not being as strong as Popper implies.

    20% picked this

  5. the irrelevance of experimentation for

    Fails Both: irrelevance

    Neither passage is making the extreme and counterintuitive claim that experimentation is completely irrelevant and worthless when it comes to trying to disprove a scientific theory.

    1% picked this

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