Flaw in the Reasoning—SN. The correct answer choice is (A)
The stimulus contains a series of conditional statements, and the logical flaw results from how these statements relate to each other. To fully describe how this flaw occurs takes a bit of effort, and some patience on your part.
Note that the first sentence in the stimulus is the conclusion. While there is no explicit conclusion indicator identifying the first sentence as the conclusion, it is supported by the second sentence, which begins with “for,” a premise indicator.
The conclusion is that humorous television advertisements are the only effective ones. This is a very restrictive conclusion, and can be restated as “television advertisements must be humorous in order to be effective.” Using “E” for “effective” and “H” for “humorous:”
- AdE AdH
The connection between humor and effectiveness offered by the argument has to do with the ability of an advertisement to convey its message. This connection is seen most clearly by beginning with the last sentence of the stimulus, which tells you that an advertisement must convey its message (“CM”) to be effective. This also is a conditional relationship:
- AdE AdCM
The second sentence in the stimulus is a premise providing the conditional relationship that if something is humorous (“H”), then it will hold a person’s attention long enough for a message to be conveyed (“HPA-CM”):
- H HPA-CM
The conclusion results from a Mistaken Reversal of this conditional relationship in the second sentence. Instead of the relationship actually contained in the second sentence, just described as
- H HPA-CM
the argument treats this term as
- HPA-CM H
This presents a bit of difficulty, because we now need to consider this new, mistaken relationship from the perspective of its contrapositive to fully understand the implications of the mistake. The contrapositive is:
- H HPA-CM
This representation provides that “if something is not humorous, then it cannot hold people’s attention long enough for a message to be conveyed.” Taking this a step further, if something cannot hold people’s attention long enough for a message to be conveyed, then it will not, in fact, convey its message. So, an inherent implication of this Mistaken Reversal is this relationship:
- H CM
The contrapositive of this relationship is:
- CM H
While rather tedious, this more in depth examination of the Mistaken Reversal was necessary, because it provides us with the term:
- (CM H)
used by the stimulus to reach the conclusion. So, all together, this is the invalid argument contained in the stimulus:
- Premise: AdE AdCM
Premise: CM H (the result of the Mistaken Reversal)
Combined: AdE AdCM AdH
Conclusion: AdE AdH (dropping the common term, “AdCM”)
So, your prephrase in this Method of Reasoning—Flaw question is that the argument is flawed because it assumes the Mistaken Reversal of the relationship in the second sentence: it treats being humorous as if it were necessary to convey a message, when the premise actually provided that being humorous is sufficient to hold people’s attention long enough for a message to be conveyed.
Answer choice (A): This is the correct answer choice, because it describes the Mistaken Reversal detailed above. In this choice, the phrase “nothing but humor” indicates that humor is necessary for something to attract a person’s attention and hold it long enough for a message to be conveyed.
Answer choice (B): This choice is incorrect because it is inconsistent with the stimulus. In the second sentence, the stimulus expressly treated attracting a person’s attention as distinct from holding a person’s attention long enough for a message to be conveyed.
Answer choice (C): In the last sentence of the stimulus, the condition presented as necessary for an advertisement’s being effective was that the advertisement must convey its message. This necessary condition was not then treated by the argument as if it were a sufficient condition. Instead, as described above, the Mistaken Reversal that actually occurred in the stimulus involved being humorous.
Answer choice (D): The word “effective” was not treated ambiguously in the stimulus. The word was used twice, and on each occasion was used in the sense of producing an intended result.
Answer choice (E): The stimulus did not imply that an advertisement’s only purpose is to convey its message. Instead, the argument implied that an advertisement is effective only if it conveys its message.