#15 - Loggerhead turtles live and breed in distinct groups

[miriamson07]

Hello,

I did choose answer choice D here, but this question felt quite tricky! I wonder how someone with little knowledge about geography might be able to assume that the “Japanese waters 10,000 kilometers away” are not in the Atlantic. Because if those Japanese waters WERE in the Atlantic, then it would seem like answer choice D was supporting the reasoning.

Perhaps it’s common knowledge to know that “Japanese waters 10,000 kilometers away” wouldn’t be the Atlantic? Please let me know, thank you.

[Amber Thomas]

Hi Miriamson!

I understand why this question is tricky-- however, we do have sufficient context clues to figure out our answer!

We know the following:
1) Loggerhead turtles exist in distinctive groups-- Pacific and Atlantic
2) New evidence indicates that Pacific loggerheads that feed near the Baja peninsula hatch in Japanese waters 10k km away
3) Our evidence for this is that 95% of the DNA samples taken from Baja turtles match the turtles at Japanese loggerhead nesting sites

So, even with no geographical context, we can infer that both the Baja Peninsula and Japan are in the Pacific Ocean, because the stimulus tells us that Pacific loggerheads live/breed there. It is established in our first premise that Pacific/Atlantic Loggerheads live and breed separately, so we can assume that Pacific Loggerheads do so in the Pacific, and Atlantic Loggerheads do so in the Atlantic.

This allows us to choose Answer Choice D-- maybe ALL loggerheads, both Pacific and Atlantic, Baja and Japanese, have a 95% DNA similarity. Therefore, that wouldn't be sufficient evidence to prove that the Japanese hatchlings then go on to feed near the Baja peninsula.

I hope this helps!

[Garrison Mitchell]

Hello this is my first posting so a little hesitant, but here we go. I will be referencing the above question for one example as this is the one I am struggling with and Weaken: Specialized Knowledge (December 2003, LR 1, #20) for the other example as I am comfortable finding what weakened the argument in the 2nd example, but I believe there are two different instructions on what the test-taker should be doing for those two examples. Mainly I had a question on what I should be focusing on for the Weaken questions. I grasp that depending on the question stem that can vary. I understand that I should focus on the conclusion as its most likely that is what is going to be impacted.

For the Loggerhead Turtle question the question stem says, "most seriously weakens the reasoning above?" in the explanation (Video explanation), the instructor said that we should, "attack the premise - the DNA, it was an argument built on DNA". With this example there was only 1 premise it is was the only evidence and the explanation video said we should attack the premise as that is what happens 99% of the time when there is only one evidential piece of support. Is attacking the premise the correct path when we have that wording in the question stem above 'weaking reasoning' or is there another reason I would know to attack the premise such as, attack the premise when the argument solely rests on a single piece of evidence? I was focused on the conclusion looking to prove the conclusion wrong.

While on the Weaken: Specialized Knowledge (December 2003, LR 1, #20) Then on this example the stem says, "most seriously weakens the argument?" On this one I focused on the conclusion due to the wording of the question and got the answer correct. Would this one be correct to attack the conclusion as there was what appeared to be a leap in logic?

Sorry if the above was not clear. Just wanting to make sure I know the rules and when to apply them.

Thank you, Garrison

[Jeff Wren]

Hi Garrison,

Welcome to the forum! There's no need to be hesitant asking questions; that's what the forum is here for.

First, there's no significant difference in meaning between the wording of these two questions that you cite; they are both Weaken questions and you solve them the same way as any other Weaken question.

As for how you solve Weaken questions, the first step is to read and carefully analyze the argument in the stimulus, taking note of the conclusion but also analyzing the premises and thinking about the relationship between the premises and the conclusion (i.e. how well or poorly the premises support the conclusion). By the way, this is something that you should do for every stimulus that contains an argument, not just for Weaken questions. Understanding the reasoning in any argument is critical for all LR question types, not just Weaken questions.

As for exactly how to Weaken an argument, in some cases the correct answer will attack a premise. Since the argument is relying on the premises for support, any answer that attacks a premise will weaken an argument. However, in many cases, the correct answer will not attack a premise, but rather attack the conclusion, usually by showing that the conclusion does not logically follow from the premises. In other words, the correct answer will show that the conclusion may not be true even if the premises are true (i.e. there is a gap in the logic between the premises and the conclusion).

If you have "The Logical Reasoning Bible," you'll see that both of these strategies are described under the "How to Weaken an Argument" section in the Weaken question chapter.

Basically, the correct answer can weaken the argument either way and you simply need to consider each answer and what effect it has on the argument. If the answer casts doubt on the conclusion, (even by attacking a premise on which the conclusion relies), that's what you're looking for.