Self-study
Although the first humans came to Australia 56,000 years ago and undoubtedly brought new diseases with them, Conclusion human-borne diseases probably did not cause the mass extinction of large land animals and birds that took place over the following 10,000 years. █████ ████ ████ ████ ██ █████████ ███████ ███████████ ██ █████ ███ ████ █████ ███ ██ ███ ████████ ███████ █████████ █████ ██ █████ ██ ███████ ██████ ████ ████ █████████ ████████
Method of Reasoning
The argument starts by describing a scenario (humans going to Australia and bringing diseases), moves to a conclusion (human-borne diseases likely didn’t cause the extinction of large land animals and birds), and provides a premise to support the conclusion (more than 55 species disappeared and no one disease could be fatal to animals across that many species).
Identify and Describe Flaw
This argument commits a flaw of erroneously moving from singularity to plurality. The premise of the argument simply states that no individual disease (singular) could be fatal to animals across all 55 of the species that disappeared, and then the argument concludes that human-borne diseases (plural) likely didn’t cause the extinction of the 55 species. Although a single disease may not have been able to kill all of the animals, it’s possible that a large array of human-borne diseases could’ve killed the animals.
21.
Which one of the following █████████ ████████ ██████ █████████ ████ ██ ████ ████████ ██ ████ ██ ███ ████████ ██████
a
Even though high ████████ █████ ███ ████ ██ ██ ████████ █████████ ████ ████████ █████ ████████ ███ ███ █████ ███ ███████ ████████ █████████ ██ ██ ████ ████ █████ ████ ████ ██ ███ █████ ███ ████ ████████ █████ ███ ███ ██████ ████████████ ████████
Wrong flaw. (A) reasons that although high interest rates can lead to an economic downturn, and rates have been rising, the rates probably didn’t cause the current downturn because high rates aren’t always harmful. (A) is flawed because of its ambiguity. Were the rates harmful or not? We don’t know. The stimulus, alternatively, is flawed because of its use of a premise about a singular part of a set (a singular disease) to conclude something about the entire set (all the human-borne diseases brought to Australia).
b
Even though I ███ ███ ████ ██████ ███ ███ ███ ███ ████ ███████ ███ ███ ██ ██ ████ ██ ██████ ██ ██████ ███ █████████ ███████ ███████ █████ ███ █████████ ███ ████ █ ██████ ██████ ███ █ ██████ ███████ █████ ███ ███████ ██ ██ ██ ████ ██ ███ ████ █████ ███ ████████
The argument starts by describing a scenario (the two people can both fix some things), moves to a conclusion (they won’t be able to repair the apartment without outside help), and provides a premise to support the conclusion (neither of them, individually, can fix both the door and window). This commits the same flaw as the stimulus of moving from singularity to plurality. (B) reasons that since neither person, individually, could fix the door and window, it’s not possible they could fix the door and window together. It’s possible that one person could fix the door and the other person the window.
c
Even though Lena, ████ ███ ████ █████ ████ ██ ██ ███ ██ ██████ ████████ █████ ███ █████ ████████ ████ ████ ████████ ██ ████████ ████ █████ ███ █████ ██ ███ ████ ███████████ ████ ███ ██ ███ █████████ ████████ ██ ███ ████████ █████ ██ ███ █ ██████ ███ ████ ███ █████ ██ ████ █████
Wrong flaw. (C) reasons that because Lena, Jen, and Mark don’t all like any of the five restaurants near the theater, they’ll likely go home after the show. (C) errs because it fails to consider outside possibilities that would keep all of them from going straight home. For instance, one of them may be willing to go to a restaurant they don’t like or they may be willing to drive further than the immediate vicinity of the theater for food. The stimulus, meanwhile, errs because it uses a premise about a singular disease to draw a conclusion about all human-borne diseases brought to Australia.
d
Even though this ████████ ██ ██████ ████████ ██ ████████ ██ ██████ ████████████ ██ ██████ █████ ████ ████ ███ ████ ███ ████████ ██ ███ ████ ███████ █████ ██ ███ █████ ████ ███ ████ █████████ █████████ ██████ ██ ███ ███ ████████ ███████ ████ ██ █████ ████
Wrong flaw. (D) reasons that since most art from the last 100 years isn’t great, and the referenced painting was likely painted 40 years ago, the painting probably isn’t legitimately great. (D) errs because it fails to consider that the painting may be an outlier. While most art from the last 100 years may not be great, the referenced painting could be an exception. The stimulus, meanwhile, isn’t flawed because of a failure to consider an outlier, but rather because the stimulus’ premise is about a singular disease and a conclusion is then drawn about a lot of diseases.
e
Even though the █████████ ███████ ████ ███ ██████ ███████ ██████████ ██ █████████ ███████ ███ ████████ ██ ███ █████████ █████████ ██ ██ █████████ ██ ███ ████ ████ ██████ ███ ███████ ███ ███████ ██████ ██ ███████ ████ ███
Wrong flaw. (E) reasons that since the influenza vaccine sometimes reduces the severity of influenza symptoms, it’s wrong to say that some people who get the vaccine don’t benefit from it. (E) errs because it treats a “some” statement as if it’s absolute. Just because some people notice a reduction of their influenza symptoms after being vaccinated, that doesn’t mean that there’s never been a person who derived no benefits from the vaccine. The stimulus, alternatively, doesn’t err because of a “some” statement, but rather because it erroneously moves from singularity to plurality.