Question

Which one of the following uses flawed reasoning that most closely resembles the flawed reasoning used in the argument above?

• A. All economists know linear algebra. All physicists know relativistic mechanics. Wilma is both an economist and a physicist. Therefore, Wilma knows both linear algebra and relativistic mechanics.
• B. All cars made by Chord are very well made. All cars made by Fysler are very poorly made. Half of the cars on Jim's lot are very well made and the other half are very poorly made. Therefore, half of the cars on Jim's lot are Chords and half are Fyslers.
• C. All players on the Wildcats have brown hair. All players on the Razorbacks have red hair. Members of the Moye family are on both the Wildcats and the Razorbacks. Therefore, some members of the Moye family have brown hair and others have red hair.
• D. All typists who practice at least one hour per day can type one hundred words per minute. But some typists who do not practice can also type one hundred words per minute. Mike, a typist, practices thirty minutes per day. Therefore, Mike types fifty words per minute.
• E. All halogen gases are toxic to humans. All non-radioactive noble gases are non-toxic to humans. "Nobagen" gas is a mixture of a halogen gas and a noble gas. Therefore, "nobagen" gas is moderately toxic to humans.

Hint:

In parallel flaw questions, abstract the logical error. Don't focus on the subject matter. The error in the referenced arguments is "ignoring alternatives." The error in option (B) is "ignoring alternative car brands that could be well made." The abstract structure is identical.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
This is a parallel reasoning (flaw) question. We must first identify the logical flaw in a preceding argument and then find the option that contains the same type of error. The most likely intended reference for "the argument above" is the pattern of reasoning from questions 20 and 21.

Step 2: Identifying the Flaw:
The flaw in the arguments about internet cafes (Q20) and landlines (Q21) is the same: the argument assumes that because the primary, most obvious function of a thing is being replaced or is no longer unique, the thing as a whole is obsolete. This flaw ignores other possibilities. For internet cafes, it ignores other potential services. For landlines, it ignores other potential uses. In essence, it mistakes one sufficient condition for a necessary one (e.g., "Internet access is a reason to have an internet cafe" is treated as "The only reason to have an internet cafe is for internet access").

Step 3: Analyzing the Options for a Parallel Flaw:
- (A) This argument is logically valid.
- (B) This argument contains the target flaw. The premises state that being a Chord is a sufficient condition for being well made (Chord \(\rightarrow\) Well Made). The conclusion commits the fallacy of affirming the consequent, treating it as a necessary condition (Well Made \(\rightarrow\) Chord). It ignores the possibility that other brands of cars could also be well made. This directly parallels the flaw of ignoring other possibilities (other services at cafes, other uses for landlines).
- (C) This argument is logically valid.
- (D) This is flawed, but the flaw is different. It's a non sequitur; the conclusion about typing "fifty words per minute" is completely arbitrary and has no basis in the premises.
- (E) This is the fallacy of composition. It assumes a mixture will have properties that are an average of its parts. While this involves an assumption, the structure is about parts and wholes, which is slightly different from the flaw of ignoring alternative categories seen in the reference arguments and option (B). The flaw in (B) is a more precise match.

Step 4: Final Answer:
The reasoning in option (B) is flawed because it assumes that Chords are the only well-made cars and Fyslers are the only poorly made ones, ignoring other alternatives. This is the same type of error as assuming internet access is the only service offered by internet cafes or that communication is the only use for landlines.