Q12 - Biologists have noted reproductive

[oslo90066]

I chose C by POE, but I do not understand why it is correct. If the dioxin passes the fish downstream rapidly, how could it affect the fish if it decomposes very slowly? Also, how would it persist in the environment long enough to affect the fish if it is part of the current?

[ManhattanPrepLSAT1]

This is a very difficult question, and one that taught me more about the LSAT than any other logical reasoning question. I'll admit I missed this question when I took this LSAT, and it took me months to finally understand what the LSAT was asking me to do.

There is something more widely applicable than just the following explanation going on here, but it's a bit technical so I'll leave it out for now.

The conclusion of the argument is that "dioxin is unlikely to be the cause." The evidence for why dioxin is not the cause is that "when the mills shut down the hormone levels of the fish return to normal" and that "dioxin decomposes slowly in the environment."

That means that dioxin should still be present when the mills shut down, because it decomposes slowly. And yet the hormone levels of the fish return to normal. So if dioxin were the cause, how could it be that the hormone levels have returned to normal? Dioxin present in the environment and the hormone levels returning to normal is not consistent with dioxin being the cause. But if normal river currents take the dioxin far downstream within a couple of hours, then dioxin isn't in the environment when the hormone levels return to normal, making it more likely that dioxin is the cause!

[alex.chasan]

this one is still giving me a lot of trouble. . .I agree that the conclusion is that dioxin is unlikley to be the cause of reproductive abnormalities in fish immediately downstream of paper mills, and the author is basing that on the premises that normal hormone levels return very quickly during during shutdowns and that dioxin decomposes very slowly.

Actually it seems like the second premise (that dioxin decomposes slowly) actually weakens his argument and is really a counter-premise.

But if (C) is correct, that STILL doesn't tell us ANYTHING about fish that are "immediately downstream of paper mills" which is the subject of the argument. Seems entirely out of scope. If dioxin gets carried away quickly, it's more likely to STRENGTHEN the argument than anything else. Think about it; mill shuts down, water right near the mill gets clean pretty quickly, and that's why hormone levels return to normal so fast -- b/c the river current is fast.

The "decomposes very slowly" just seems not to matter since it weakens his conclusion anyway, and who's to say what speed is meant by "very slowly"? Minutes, hours, weeks?

[ManhattanPrepLSAT1]

Hmmm.

If the dioxin filled water is flushed far downstream, then the dioxin is no longer present in the environment. So now we have clean water and the hormone levels return to normal. That sounds like it is the dioxin causing the abnormal hormone levels. So, answer choice (C) strengthens the claim that dioxin is the cause and weakens the conclusion that dioxin is not the cause.

This is a really hard question to wrap your head around and structurally what they're doing is very complex. Now that I know what I'm looking for, I'm seeing it regularly on the LSAT (not every test, but every year for sure).

[Jordan.weber]

First of all, thanks for the help. This is great. In your first reply you said the following -

There is something more widely applicable than just the following explanation going on here, but it's a bit technical so I'll leave it out for now.

Could you mention (if it's possible to do it relatively briefly) what the more technical thing is? I'm relatively experienced with formal logic, so if it involves that, I can probably follow. Thanks!!

[ManhattanPrepLSAT1]

Let me try and explain this from an abstract perspective.

This question does not rely on conditional logic. While conditional logic is one of the major concepts tested in the logical reasoning section, the other major concept tested is causation.

This argument concludes the denial of a causal relationship - it concludes that dioxin is not the cause of the elevated hormone levels.

On weakening questions, when the argument posits a causal relationship, we seek an answer choice that does one of the following three things.

1. Provides an alternative cause
2. Provides an example of the presumed cause without the presumed effect
3. Provides an example of the presumed effect without the presumed cause.

Since these are the ways to weaken a causal relationship on the LSAT we would expect the test-writer to follow one of these three paths to denying a causal relationship - and they do. The evidence for the claim that "dioxin is unlikely to be the cause" is that the dioxin was supposedly present in the environment and yet the fish recovered normal hormone levels - cause without effect.

To undermine an argument that denies a causal relationship in the conclusion, determine which of the three possibilities is given for undermining a causal relationship. In this case, it's the second (we still have dioxin, since it decomposes slowly, but the fish recover). Then to undermine this causation-destroying argument, we need to say that either the presumed cause (dioxin) was not actually present or that the presumed effect (abnormal hormone concentrations) was present. This will undermine the test-writers evidence for why dioxin is not the cause. The correct answer says that dioxin was washed far down stream - meaning that dioxin (the presumed cause) was not present. Alternatively, we could have found an answer that said that the fish actually had not recovered normal hormone levels (the effect was still present).

If the evidence had been effect without cause, we would have sought in the answer choices one that stated that the cause was actually present, or that the effect was actually not present. In the many instances of this construct appearing on the LSAT, we have not seen the test-writers turn to alternative cause for undermining a causal relationship. So we should expect to see either cause without effect or effect without cause as the evidence for a conclusion that denies a causal explanation.

This construct has appeared here and there over the years, but has not appeared so frequently that it's a make or break concept.

I hope this helps!

[mrudula_2005]

Your explanations on this question have been phenomenal and I completely understand how C works here. So thank you!

However, what's so off about D and maybe even E? The conclusion of the argument is that "Dioxin is unlikely to be the cause of [reproductive abnormalities]"

The conclusion of this argument is one of (presumed to be present) cause without effect (hormone concentrations recovered to normal), but D could show that there WAS indeed some effect (that reproductive abnormalities may have resulted) when it talks of "some fish NOT recovering rapidly from the physiological changes that were induced by changes in hormone concentrations" - so while the hormone concentrations may have reverted back to normal while dioxin was still chilling around, the whole part of the conclusion that actually matters in the causal relationship (reproductive abnormalities) may have indeed come into effect in some cases. Or does the "some" kill it or is assuming "physiological changes" might mean "reproductive abnormalities" too much of a stretch?

As for E, if the connection between hormone concentrations and reproductive abnormalities is not thoroughly understood, then dioxin could still be responsible somehow for the reproductive abnormalities even if it wasn't via its ability to alter (or apparently not alter) the concentration of hormones in fish.

Or am I just trying too hard to stretch things here and make them work?

Thanks!!

[ManhattanPrepLSAT1]

The LSAT writer is so tricky sometimes...

Let's look at answer choice (D) first. You're last point about answer choice (D) is why I would eliminate it; we don't know that the reproductive abnormalities discussed in the stimulus were physiological changes. Also, do we really expect fish to recover from physiological changes? Maybe yes, but maybe not. In which case the physiological changes could be caused by dioxin, yet not something they would recover from.

As for answer choice (E), if you think about it, the connection not being well understood doesn't really advocate either that dioxin is the cause or that it's not the cause. Both possibilities are equally likely if the connection is not well understood. We really want to undermine the idea that dioxin is not the cause, which means we want an answer choice that would suggest that dioxin is the cause.

Great questions! I really think this is one of LSAC's greatest.

[Nikefigure]

Can someone please explain why b is incorrect?

[ManhattanPrepLSAT1]

Dioxin decomposes slowly in the environment immediately downstream of the paper mill - stated in the argument. That dioxin decomposes at various rates is consistent with the notion that it decomposes slowly in this particular area. Had answer choice (B) established that dioxin decomposes quickly in the environment - it'd be something to consider.

But this doesn't change the rate at which dioxin decomposes in the area discussed in the stimulus.

Make sense?

[chike_eze]

Wow! Dumbfounded!

I actually got to (C) after staring at the prompt for 4+ minutes and saying "so what?" and "not relevant" to most of the other answer choices. To be honest, I totally misunderstood the argument to suggest that the author's undermining attempt of the cause-n-effect relationship was incomplete.

I figured that the dioxin wasn't swept downstream during occasional shutdowns, but the author assumed this to be the case, which is why he undermined the argument by stating a "cause without effect".

I looked at (C) and thought, O... I guess this ensures that the dioxin was pushed downstream to the fish. This would help fill the gap in the argument that...
blank! O wait, even if my twisted reasoning was accurate, I just strengthened the author's argument! Gosh!

This question was plenty ugly

However, after reading Matt's explanation, it makes sense. At least I think it does.

The author's argument is based on undermining another argument. We undermine his argument by neutralizing his undermining of the other argument. In effect, we weaken his argument, by strengthening (or defending) the argument he attempted to weaken.

Unreal! My head's still spinning lol!

[ManhattanPrepLSAT1]

Hey Chike, you've got it right!

It's a tough question. One that almost always makes someone's top 10 most challenging LR questions ever.

[jamiejames]

I wanted to choose C, but I ended up choosing D, because in the prompt, it says that the fish recovered "relatively quickly," and C says that the river current carried the dioxin downstream in a few hours, and the disparity in time between the two threw me off. However, after reconsidering the question, the use of "relative" and "few" implies that quickly could be 5 minutes, or 10 hours, and a "few" could mean two hours or 10.

Furthermore, if it did take a couple of hours for the dioxin to move downstream, but the fish began to recover after 30 minutes (relatively quickly,) this shows that even a slight decrease in dioxin improved fish health a great deal, showing that dioxin must be the cause talked about in the prompt.

[cdjmarmon]

I’m still not seeing how C is a weakener. If anything I see it as a strengthener.

The argument says D cannot be the cause because fish recover quickly when the mill is shut down and D decomposes very slowly.

To weaken I need to say D is the cause of the fish abnormalities.

So if I say the normal river current carries D far down stream in a few hours then the fish immediately downstream will be unaffected because D wont be present and the fact it decomposes slowly doesn’t even matter anymore.

I see that as strengthening the argument.

[shirando21]

I like Matt's explaination.

I have done type training on most questions types, but I haven't done it for weaken questions. and I also find among the questions I now miss, weaken appears a lot.

my question might be silly, but what is a good reason to eliminate A?

[chike_eze]

I like Matt's explaination.

I have done type training on most questions types, but I haven't done it for weaken questions. and I also find among the questions I now miss, weaken appears a lot.

my question might be silly, but what is a good reason to eliminate A?

A) can be quickly eliminated because in the current context it does not matter who paid for some of the studies. "... Fish recover normal hormone concentrations relatively quickly" is provided as fact in this question. Therefore, unless we get actual evidence disputing the result of the study, we are to accept it as given.

Most times, our job will be to attack the relationship between Premises given and conclusions drawn, not the premise directly. Of course there are exceptions

[chike_eze]

I’m still not seeing how C is a weakener. If anything I see it as a strengthener.

The argument says D cannot be the cause because fish recover quickly when the mill is shut down and D decomposes very slowly.

To weaken I need to say D is the cause of the fish abnormalities.

So if I say the normal river current carries D far down stream in a few hours then the fish immediately downstream will be unaffected because D wont be present and the fact it decomposes slowly doesn’t even matter anymore.

I see that as strengthening the argument.

The key here is the difference between immediately downstream and far downstream in the question stem and option C respectively. The fish are immediately downstream in the question stem, while the river currents pushes the dioxins far downstream in Option C.

I re-read this game after a few months, and it still took me a few minutes to remember the different qualifiers "near vs. far".

[texasrangersjb]

This one is really tough, and I missed it initially. Here's my revised train of thought.

Reproductive issues in fish have been noticed by biologists. One potential cause is that a mill directly upstream is releasing dioxin which can cause hormone alterations in fish. This in turn could be causing the reproductive issues.

However the argument says that dioxin can't be the cause, because even when mills shut down, dioxin stays in the environment for a while, yet fish's hormones quickly normalize. We would expect the hormones to NOT normalize even when the mill shuts down if dioxin was the cause. So he's basically implying that there could be something else coming from the mill that is affecting these fish, because even when the mill shuts down, dioxin should still be in the general area of the fish, and if it was causing these hormone fluctuations, it wouldn't matter if the mill shut down occasionally.

But (C) says that dioxin is carried far downstream relatively quickly. Ahh, so that's why the fish's hormones stabilize. Sure, dioxin doesn't decompose in the environment, but it's just far away from the fish. Once the mill stops, the dioxin flows right on past the fish, and the hormones return to normal.

[donghai819]

All posts are helpful. But I wondered if Noah or Patrick would provide some thoughts?

[maryadkins]

This question has been pretty thoroughly explained by Matt and elaborated on by others in the thread so we're going to leave it here unless there are specific questions left unanswered by the discussion above!