#23 - Anthony: It has been established that over 80 percent

[Dave Killoran]

Complete Question Explanation

Method-Argument Part, CE, #%. The correct answer choice is (D)

In the stimulus, Anthony floats the idea that marijuana is a gateway drug, since 80% of heroin users previously used marijuana. Judith counters with an example—100% of heroin users previously used water—that shows that Anthony's reasoning is suspect.

Answer choice (A): Judith does not show that Anthony's statistics are inaccurate, just that he can't use them to validly draw the conclusion that he draws.

Answer choice (B): This is the most attractive wrong answer. The answer is incorrect because Judith doesn't take Anthony's conclusion and use that to derive absurd consequences, but instead uses the same reasoning as Anthony to show that his reasoning can be used to draw an absurd conclusion. In other words, this answer says that Judith takes his conclusion and goes from there, which does not happen.

Answer choice (C): Judith is not attempting to show that everything promotes heroin usage; she's focused on the bad reasoning Anthony used.

Answer choice (D): This is the correct answer choice. In her reply, Judith shows that the the reasoning that Anthony used to draw his conclusion is problematic. she shows, via analogy, that thinking in the same way he does will in certain circumstances result in conclusions that are clearly false.

Answer choice (E): This answer is too strong. Her reply doesn't destroy the idea of "ever" using stats in any situation to show a causal connection, just that in this particular case it doesn't work.

[deck1134]

Why is (B) wrong here? Judith DOES show that such reasoning can lead to absurd consequences. I was able to narrow it down to (B) and (D), but am not sure why (D) is more correct than (B).

[hwkim93]

My thought was that since the "statement" mentioned in (B) is referring to Anthony's conclusion (i.e. smoking marijuana definitely leads to heroin use) and his conclusion by itself doesn't necessarily lead to absurd consequences, (B) was wrong.

On the other hand, I thought (D) captured Judith's reply correctly. Anthony is using correlational evidence (i.e. 80% of heroin users have used marijuana) to say that there was causation -- smoking marijuana leads to heroin use. (D) captures this error in Anthony's reasoning by saying that such reasoning can lead to clearly false conclusions. The example Judith gives for a clearly false conclusion is that because a 100% of heroin users have drunk water, Anthony's reasoning allows us to say that drinking water leads to heroin use -- something that is clearly false.

[James Finch]

Hi HW,

Excellent, that's correct! In this Method question, Judith is using an analogy to illustrate the flaw in Anthony's reasoning--showing that mere correlation doesn't prove causation. This is done by showing that a clearly absurd conclusion can be drawn using the same method, as (D) describes. (B), on the other hand, describes an inference made from Anthony's conclusion (which is nowhere in Judith's statement) rather than a paralleling of his flawed reasoning.

Good job!

[na02]

Why is the answer not E?
I get how D is correct, but is E wrong because Judith does say "maybe ... does lead to ..." and hence doesn't "question the possibility of ever"?
I was quite confused because Judith refers to "citing those statistics" and E also includes "basis of statistical evidence."
Any clarification would help.

Many thanks!

[Dave Killoran]

Why is the answer not E?
I get how D is correct, but is E wrong because Judith does say "maybe ... does lead to ..." and hence doesn't "question the possibility of ever"?
I was quite confused because Judith refers to "citing those statistics" and E also includes "basis of statistical evidence."
Any clarification would help.

Many thanks!

The "ever" is too strong here and knocks this answer out. Her reply doesn't destroy the idea of "ever" using stats in any situation to show a causal connection, just that in this case it doesn't work.

Thanks!