Self-study
Passage A.
P1
████ ████████ ████ ████████████ ██ ███ ██████████ ██ ███████ ████████ ███ █████ ██ ████████ █████████ ███ ███████████ █████ ██ ███████ ██ ██████ ██ █████ ██████ ███ ████████ ███ ████ █████ ████ ███ █████ ███ ██████ ███ █ ██████ █████ ████ █████████ ███ ███████████ ███
Intro to Popper ·
Power of negative evidence
A single black swan disproves that all swans are white
Asymmetry ·
Between positive and negative evidence
Positive evidence has no value
Requirements of Science ·
Search for negative evidence; making falsifiable predictions
P2
████████ ████████ ███ ██ ███ ███████ █████████ ████ ███ ██████████ ███████ ███ ██████ █████████ ██████████ █████ ███
Critique of Popper ·
Negative evidence is not as powerful as he believes
Premise ·
Theories have to work together to entail predictions
So a failed prediction means some theory is false, but it's unclear which one.
███████ █
P3
████ ███ ██████ ██████ ███ ███████████ ███████████ █████████ ██ ███████ ███ ██████ ████ █████ █████ ███████████ ██ ████████ ████ ███ █████████ ███████████ █████ ███ ████ ██ ███ ███ ███ ███ ███████ ███████ ███ ██████████ ██ █████ ████████ ███ ██ ███ █████████ ███████████ ███ ████ ██ ███████ ███████ ██ ███ ████████ ██ ███████ ███
Prediction ·
Orbit of Uranus
Multiple theories working together to entail the predictions. This can be framed as an application of Passage A.
Prediction ·
Failed
At least one of the theories is wrong.
Explanation ·
There's another planet
Scientists discovered Neptune.
P4
█████ ████████████ █████ █████ ████████ █████ █████████ ███ █████ ██ ████████ ███
Prediction ·
Orbit of Mercury
Prediction ·
Failed
Perhaps Newton's laws are incorrect or perhaps there's another planet.
Explanation ·
Newton's laws are incorrect
Einstein's general theory of relativity is more correct.
Passage Style
24.
The author of passage A █████ ██ ████ ██████ ██ ████ █████ ███ ██ ███ █████████ ███████ █████████ ██ ███████ █ ██ ███████ ███ ███ █████ ████ ██ ███ ████ ████████ ██ ███████ ██
a
the discovery of ██████
Passage B doesn’t discuss the discovery of Uranus. It discusses the discovery of Neptune.
b
the initial failure ██ ████████ ████ ██ █████████ ███████ ████████ █████
The last sentence of passage A says negative evidence is rarely conclusive in disproving a theory. The discussion of Uranus in passage B supports that claim by giving an example where negative evidence was obtained, but that evidence didn’t disprove a theory. Observations of Uranus’s orbit contradicted what Newton’s laws said should happen. This was negative evidence against Newton’s laws. But the problem wasn’t actually that Newton’s laws were wrong. The problem was just that an overlooked planet (Neptune) was affecting the orbit. Once that planet was accounted for, everything aligned with Newton’s laws.
c
the ultimate failure ██ ████████ ████ ██ █████████ ███████ █████████ █████
This anti-supports the last sentence of passage A, which says negative evidence is rarely conclusive in disproving a theory. But the discussion of Mercury is an example of negative evidence succeeding in disproving a theory. Observations of Mercury’s orbit contradicted what Newton’s laws said should happen. This was negative evidence against Newton’s theory, and cause scientists to doubt and ultimately reject that theory.
d
the failure to ████ ██████
This anti-supports the last sentence of passage A, which says negative evidence is rarely conclusive in disproving a theory. But the discussion of Mercury, and the associated failure to find Vulcan, is an example of negative evidence succeeding in disproving a theory. Observations of Mercury’s orbit contradicted what Newton’s laws said should happen. This was negative evidence against Newton’s theory. There were two explanations: maybe Newton’s laws are just wrong, or maybe “planet Vulcan” is throwing off the calculations. But Vulcan was never found, and scientists concluded that Newton’s laws were indeed wrong. In other words, the failure to find Vulcan ruled out an alternative hypothesis about what the negative evidence signified, and so helped to disproved a theory.
e
the success of ██████████ ███████ ██████ ██ ██████████ ██ ██████████ █████████ █████
The last sentence of passage A says negative evidence is rarely conclusive in disproving a theory. In other words, we’re trying to support the idea that negative evidence doesn’t always disprove theories. But (E) is an example of positive evidence helping to prove a theory. (Observations of Mercury’s orbit matched what Einstein’s theory predicted, and so those observations were positive evidence of that theory.)