Biologists have noted reproductive abnormalities in fish that are immediately downstream of paper mills. One possible...

Serra on March 2 at 07:49PM

How to identify the "argument"

Biologists have noted reproductive abnormalities in fish that are immediately downstream of paper mills. One possible cause is dioxin, which paper mills release daily and which can alter the concentration of hormones in fish. However, dioxin is unlikely to be the cause, since the fish recover normal hormone concentrations relatively quickly during occasional mill shutdowns and dioxin decomposes very slowly in the environment. Which one of the following statements, if true, most seriously weakens the argument? I Identified the argument structure as follows: Counter P - Biologists have noted reproductive abnormalities in fish that are immediately downstream of paper mills. One possible cause is dioxin, which paper mills release daily and which can alter the concentration of hormones in fish. C - However, dioxin is unlikely to be the cause P - since the fish recover normal hormone concentrations relatively quickly during occasional mill shutdowns and dioxin decomposes very slowly in the environment. So essentially the “argument” that the question is referring to is: “However, dioxin is unlikely to be the cause, since the fish recover normal hormone concentrations relatively quickly and dioxin decomposes very slowly in the environment.” How is (C) “normal river currents carry the dioxin present in the river far downstream in a few hours” the right answer? The question asks us to identify what weakens the argument while (C) appears to strengthen the argument. I have reviewed prior lectures and still cannot find an example in them to determine where I went wrong with this question. If this is covered in material after Diagnostic 1, could you please tell me where so that I can learn the concept necessary to approach this question? Thank you!

3 Replies

Jacob on March 3 at 01:04AM

The best way to identify the argument is to look for language that examines premises, conclusions, and the linkage between the two.

Here, we start with a premise: Biologists have noted reproductive abnormalities in fish that are immediately downstream of paper mills. We then have another premise: that one possible cause is dioxin, which mills release and can alter the hormone concentration in fish.

Then notice a linkage word: HOWEVER, dioxin is unlikely to be the cause. A conclusion! Why? Because fish recover normal hormone concentrations relatively quickly during mill shutdowns and dioxin decomposes very slowly in the environment.

So that is the argument that explains why dioxin is unlikely to be the cause. Since we are looking for the answer that most seriously weakens that argument, we want to find something that indicates that dioxin IS likely to be the cause.

And that is exactly what answer C does — it weakens the reason for the argument’s conclusion. Because normal river currents carry the dioxin present in the river far downstream in a few hours, the slow decomposition of dioxin and the quick recovery of fish is no longer an indication that the dioxin isn’t the cause of the hormonal changes — instead, the dioxin is just being carried away by the current.

I hope this helps! Please let us know if you have further questions.

Serra on March 3 at 04:28PM

Ok I get it now :) Wow, this was one crafty test writer! I also looked back at Mehran’s prior explanation which now makes sense to me, as well. Thanks again, Jacob, I appreciate you taking the time to rephrase and help me understand the explanation. You were very helpful!

Ravi on March 11 at 04:14PM

@msaber, happy to hear Jacob and Mehran's explanations helped you sort out this question. Let us know any other questions you have—we're here to help!