Bunuel wrote:
Columnist: The chief of police has claimed in a recent press conference that the decline in the number of pickpockets caught on the street indicates that his department that has partly eliminated this petty crime. He might as well argue that because there are higher levels of fog over L.A., there are fewer stars in the night sky. The gentlemen of our police department, in all likelihood, have caught fewer acts of petty crime lately simply because their vigilance is haphazard, at best.
The columnist's statements, if true, best support which of the following as a conclusion?
A. Catching acts of petty crime requires vigilance above all.
B. It is possible to estimate roughly how many petty crimes are committed in the area through methods of inference.
C. Crimes unobserved due to negligence and stars unobserved due to fog stand in roughly equal proportion over time.
D. Rather than believe the chief of police, the people of the town should demand greater vigilance of the police force.
E. Pickpockets continue to carry on their petty crimes.
Official Explanation
Reading the question: we read the statements of the columnist, which turn out to be a brief rant. We don't have to criticize what the columnist said; rather, we have to draw a conclusion. We can prove by stronger terms; most likely, the correct answer choice will be not only a good conclusion, but a required conclusion. Such a choice may not be the most natural conclusion, but it will be the most objectively flawless one. That's our filter.
Applying the filter: (A) does not follow from the prompt, which gives a lack of vigilance as a failure mode here, but not necessarily how we catch petty crime above all. (B) is neither indicated nor required by the argument. Same with (C). (D) sounds natural, but it need not be true. The columnist's point might be, for example, that we can't trust the chief at all, and need to demand his replacement. That leaves us with (E).
Logical proof: we can see that (E) must be true. If the police have caught fewer acts only because they haven't been trying as hard, then there are at least as many acts as before. We apply the negation test. Suppose that pickpockets do not carry on their petty crimes. Suppose there were no more pickpockets at all In that case, the decline in pickpocket cases cannot be attributed to poor vigilance.
The correct answer is (E).