CooLAW每日真題之二

Section I: Question 2

2. Twenty percent of the population of Springhill has been to Italy at least once in the last five years, and thirty percent of the population of Springhill has been to France at least once in the last five years. Therefore, half of the population of Springhill has been to Europe at least once in the last five years.

The argument is faulty because it ignores the possibility that

(A) some of the population of Springhill has been neither to Italy nor to France in the last five years.
(B) some of the population of Springhill has been both to Italy and to France in the last five years.
(C) some of the population of Springhill has been either to Italy or to France in the last five years, but not to both.
(D) none of the population of Springhill has been to any country in Europe other than Italy or France in the last five years.
(E) none of the population of Springhill has been either to Italy or to France more than once in the last five years.

==========================================================
General Description:
This question asks you to identify the logical problem in an argument caused by failure to consider a logically relevant possibility. The best answer, then, will not merely present some possibility the argument fails to consider. Rather, it will be something the argument should have considered: a possibility that, if it turned out to be true, would tend to undermine the reasoning leading to the argument\’s conclusion.

A. Incorrect. It would not make the argument flawed to have ignored this possibility: the argument\’s conclusion is consistent with the possibility that the other half of Springhill\’s population has never been to Europe at all. Because the conclusion is consistent with this possibility, the argument does not need to address it.

B. Correct. If there were no overlap between the travelers to Italy and the Travelers to France, then the argument\’s premises would provide good evidence for its conclusion: 20%+30%=50%. But the argument has presented no reason to suppose that there is no such overlap, and to the extent that there is, the argument is undermined. That is, if some people are counted both in the Italy group and in the France group, then the two groups together do not add up to 50%. (B) describes just this problem and is the best answer.

C. Incorrect. Far from ignoring this possibility, the argument seems to be assuming that it is actual. In fact, the greater the number of people from Springhill who have been to Italy or to France in the last five years, but not to both, the stronger the argument.

D. Far from ignoring this possibility, the argument seems to be assuming that it is actual. For if there were people form Springhill who had been to other European countries in the last five years, the argument would be stronger for mentioning them.

E. Incorrect. The argument is not faulty in ignoring this possibility, because it is irrelevant: The argument is about numbers of people who have been to Italy and/or France (and thus Europe) at least once in the last five years.