Self-study
Support The experts who now assure us that genetically engineered plants are harmless are the same experts who claimed that introducing non-native plants into the wild was a good idea. ██ ██ ███ ████ ██ ██ █████████ ███ ████ ████ ██████████ ██████ ████ ██████ █ ███████ ████████ ███ ██ ██████ █████████ █████ ██ █████ ████ █████ ████ ███████████ ██████████ ██████ ████ ████ ██ ████████
Method of Reasoning
The author concludes that genetically engineered plants will be harmful. His reasoning is that the experts now promoting genetically engineered plants were previously mistaken about non-native plants, which have turned out to be harmful.
Identify and Describe Flaw
This is the cookie-cutter ad hominem flaw. The author attacks an argument by trying to discredit its proponents. But this doesn’t tell us anything about the merits of the argument itself. Even if the experts were wrong about a different subject previously, perhaps genetically engineered plants are actually harmless.
21.
The flawed reasoning in which ███ ██ ███ █████████ ████ ███████ █████████ ███ ██████ █████████ ██ ███ ████████ ██████
a
The same people ███ ████████ ████ █████ ███ ███ ████ ████████ ████ ███ ██████████ ████ ███ ███████ ██████ █████████ ██ ██████ ████████ ████ ████ █████ ███ ███ ██████████ ██ █████████
This doesn’t have the same structure as the stimulus. (A) points to an internal contradiction in some people’s arguments. By contrast, the stimulus points to an irrelevant case where some people’s views were disproved by facts.
b
The film critics ███ ██████ █████████ ████ ████ █████████ ███ ███ ████ ████ ███ ███ ███████ ███ ███ ████ ████████ ███ ███████ ███ ███████ █████████ ████ ████ ███ █████████ █ ████████ ████ ████ ███ ████ ██ █████
This is an incomplete flaw. (B) assumes that, just because Meisner’s last film was brilliant, his next one will be too. The stimulus also erroneously relies on past precedent—but the past precedent is of experts’ irrelevant opinions, not the subject in question.
Note that (B) agrees with the critics who thought that the last film was brilliant. So, the critics were allegedly right before but wrong now. By contrast, the stimulus argues that the experts were wrong before and wrong now.
c
The economists who ████ ██ ████ ███ ███████ ████████ █████████ ████ ████ ██ ████ ███ ███ ████ ██████████ ███ ██████ ██ ███████ ███ ███ ██ ███ ████ ██████████ ████ █████████ ████ ████████ ████ ███ █████████ ████ ████████ ███ ████ █████
(C) concludes that the current economic expansion will continue. The reasoning is that the economists now claiming it will soon end were mistaken about the end of the last recession.
Like the stimulus, this is the cookie-cutter ad hominem flaw. The author attacks an argument by trying to discredit its proponents. But this doesn’t tell us anything about the merits of the argument itself; even if the economists were wrong previously, perhaps the expansion will end soon.
d
Children who beg ███ █████ ████ █████ ███████ ██ ███ ████ ██████ ████ ███ ███ ████ ████████ ███ ██████ ███ ██████ ████ ████ █████ █ ████████ ████ ███████ █████ ██ ██████ ████ █████████ ███ ██████ ███ ███████████ █████
This doesn’t have the same clear flaw as the stimulus. (D) does not dismiss an argument merely on the basis of its source, the way the stimulus does.
e
The population experts ███ ███ ██████████ █████ ████ █████████ ██ ███ ████ ██████ ███ ███ ████ ████ ███ ████ ███████████ █████████ ████ █████████ ██ ███ █████ ██████████ ██ █████ ███ ████ █████████ ██ ███ ████ ███████ ██ ████ ███ ██ ███████ ██████████ ███████ █████████ █████
This is the wrong flaw. (E) concludes that, if the experts are correct in the future (if there are food shortages), it will be coincidental. By contrast, the stimulus erroneously concludes that the experts will not be correct.