Vague laws set vague limits on people’s freedom

OFFICIAL EXPLANATION

The argument can be analyzed as follows:

Premise: Vague laws set vague limits on people’s freedom.
Premise: Vague limits on people’s freedom make it impossible for them to know for certain whether their actions are legal.
Conclusion: Under vague laws people cannot feel secure. There is a new element in the conclusion—“cannot feel secure”—that must be justified. There is also an unconnected element in the premise—“know for certain whether their actions are legal”—that will likely appear in the answer choice. Unfortunately, four of the answer choices contain those two elements. Only answer choice (D) does not contain both, and as (D) also contains the “vague law” element that appears in both a premise and the conclusion, we can eliminate (D) for the moment. Given the plethora of answers that remain in contention, first examine the conditional structure that is extant in the stimulus:
Premises: Vague laws
Vague limits
~Know actions are legal.
Conclusion: Vague laws~Secure. Abstractly, this relationship is similar to: Premises: A
B
~C,
Conclusion: A
~D. The relationship that must be added to the premise to prove the conclusion is: ~C~D. Translating the diagram back to the terms used in our premise and conclusion, we need a statement like the following: ~Know actions are legal~Secure. Of course, the contrapositive of this statement would also be acceptable. Answer choice (A) is the contrapositive and thus (A) is correct.

Answer choice (B): This answer is incorrect because it has a different level of certainty than the conclusion: this answer uses the phrase “might not” when the conclusion uses “cannot.” If this flaw were corrected, the answer would be correct.

Answer choice (C): This answer is the Mistaken Reversal of the correct answer.

Answer choice (D): This answer was eliminated previously.

Answer choice (E): This answer is also the Mistaken Reversal of the correct answer. If you found yourself in trouble on this question, understanding that answers such as (C) and (E) are identical would allow you to eliminate them under the Uniqueness Rule of Answer Choices (that the correct answer must have unique properties).