#19 - Ecologist: One theory attributes the ability of sea

[Administrator]

Complete Question Explanation

Flaw in the Reasoning—CE. The correct answer choice is (D)

The argument introduces two possible causal explanations for the ability of sea butterflies to avoid predators—physical appearance or the various chemical compounds they produce. The ecologist concludes that the chemical compounds are not responsible for this ability. As evidence, she points to a study whereby each compound was tested individually, and none appeared to deter the predators.

This argument is flawed because the study was based on a questionable premise—namely, that the chemical compounds would work independently to produce the desired effect. However, what if they only work in conjunction with one another? The ecologist only tested the effect of each chemical compound independently. Even if none of them produced the effect individually, it is still possible that the compounds as a group would have a deterrent effect. This is an example of an Error of Composition.

Answer Choice (A): The ecologist never presumes the two theories are incompatible with each other. While she claims that chemical compounds are not the reason why butterflies are able to avoid predation, she never claimed that their appearance was the cause. Since we do not know the ecologist’s opinion regarding the appearance theory, the assumption described in this answer choice is impossible to prove.

Answer Choice (B): While the ecologist does draw a causal conclusion, namely, that the chemical compounds are not the reason why butterflies are able to avoid predation, her conclusion is not based solely on a statistical correlation. The evidence presented is an observation suggesting that the effect was never produced in the presence of any one chemical compound. This is not a correlation. Since the latter portion of this answer choice is an inaccurate description of the ecologist’s argument, it is incorrect.

Answer Choice (C): This is not a conditional argument. The argument is a denial of a causal argument. This answer choice discusses a Mistaken Reversal, which was never present in the stimulus.

Answer Choice (D): This is the correct answer choice. This answer choice describes an Error of Composition. The ecologist properly establishes that no individual chemical compound has a sufficiently strong deterrent effect. However, this fact does not preclude the possibility that the chemical compounds might be able to collectively produce the effect.

Answer Choice (E): Since the premises and the conclusion are not identical in meaning, this argument does not contain circular reasoning.

[sparrrkk_]

Hi,

I understand why D is the correct answer choice as I did notice how the ecologist doesn't consider that the compounds might work in conjunction to help sea butterflies avoid predation.
However, I was also considering what if the chemical compounds produce their appearance and their appearance helps them avoid predation? In this sense, wouldn't the compounds help in their ability to avoid predation? Due to this reason, I chose A initially... thinking what if it's not that the compounds are eaten but that they contribute to appearance which might be why the sea butterflies avoid predation.
I definitely get why D is correct but just want to make sure I understand why the other answer choices are wrong too.

Thank you!

[KelseyWoods]

Hi sparrrkk_!

As described above, the author does not presume that the two theories are incompatible with each other. She never states that it has to be one theory or the other, she just concludes that the chemical compounds are not responsible. So even if it is possible for the chemical compounds to cause the appearance, answer choice (A) does not describe that type of causal flaw, nor does it describe anything that occurs in the stimulus. It's okay to think of other things the author failed to consider, but if you don't find an answer choice that matches your specific prephrase, you need to broaden your prephrase a bit. In Flaw questions, the answer choice must 1) describe something that actually occurs in the argument and 2) describe a reason why the premises don't fully prove the conclusion. Only answer choice (D) meets both of those criteria.

Hope this helps!

Best,
Kelsey

[Adam354]

I thought B was suspect, but eventually went with it because I missed that "one compound at a time" could mean that not all the compounds in the set were placed in each pellet.

Since I missed that, the way I made B work was to say that there was a correlation between predator's satiation from the pellets and eating the pellets. However, even with this correlation, that does not imply a cause. This question states that it draws a conclusion about a cause from a correlation. If it said it draws a conclusion from a correlation, without a cause, it would have been stronger. The chemicals NOT causing animals to NOT eat them, does not count as a cause for them eating them, and certainly doesn't count as a cause for butterflies having chemicals, or predators avoiding them. Though I suppose that correlation could be a cause for supporting the theory that predator avoidance is due to appearance. Still though, this seems a wild interpretation, and the answer B was quite clear if the question stem wording was sufficiently inspected.

[Beth Hayden]

Hi Adam,

I wouldn't say it's about the predators being satiated by eating the pellets, more that they were not deterred by the pellets. The idea is that sea butterflies are able to deter the predators in the same way that insect repellent keeps you from getting bitten. So what is it about the butterflies that keeps predators away? Is it the way they look or chemical compounds they produce that drive away the predators?

How do you figure out which characteristic of the butterflies is repelling the predators? Well, here they isolated out the compounds to see if they got the same effect with just the chemical compounds on their own, but they didn't--the predators weren't driven away at all, they actually ate the pellets! That's not just a correlation; it proves that each individual compound could not be the cause. If the chemical was the cause, we would expect the predators to avoid the pellets, but that's not what happened. Of course the problem with that reasoning is that it ignores the possibility that the chemicals only act as a deterrent when they are together and not separated out.

Hope that helps!
Beth