Q16 - It is repeatedly claimed

[ebrickm2]

Just curious as to what exactly the conclusion is here. The construction of this seemed a bit funky. Kinda got tripped up in that conditional statement, but not sure how relevant it is. I intuited the right answer, but still would like to discuss the structure a bit.

tytytytytyty

[goriano]

The premise seems to be a conditional:
If dumping nuclear waste poses no threat to people living nearby --> locate sites in areas of dense population.

Conclusion: Dumping nuclear waste only in sparsely populated regions indicates some misgiving about the safety of such practice.

My question for the LSAT geeks is that the conclusion seems to be arrived at through taking the contrapositive of the premise, which seems (inherently) hard to weaken. So while the correct answer choice (C) discuss an alternate cause for seeking out more sparsely populated areas and makes sense intuitively, if we are looking at the stimulus from a strictly formal logic point of view, wouldn't that directly conflict with the conditional premise stated?

[timmydoeslsat]

The conclusion of this argument is the last sentence. "But the policy of dumping nuclear waste only in the more sparsely populated regions indicates...misgiving about safety..."

The only supporting evidence for this claim is 2 premises.

1. It is repeatedly claimed that people are not being threatened by being near a nuclear waste dump.

2. If the claim could be made with certainty (in other words, if the first premise could be made with certainty), there would not be a reason to NOT put sites there.

There is no contrapositive being reached here from the conclusion.

This conclusion simply jumps to one explanation for the occurrence of sites not being built near larger groups of people.

We can weaken this by pointing out alternate reasons for this like B does.

[ohthatpatrick]

I saw this question a little differently from the previous poster.

I think the conclusion here is an implicit one: "dumping nuclear waste may pose some threat to people living nearby".

Whenever an argument begins with an ascription such as "it is repeatedly claimed", "it is often assumed", "many people believe", etc. ... 98% of the time the author's purpose/conclusion is to disagree with that initial claims.

So when I see the claim of "dumping nuclear waste poses no threat to people living nearby", I see the author's conclusion as: "we should doubt this claim".

why should we doubt this claim?

If ppl REALLY believed that dumping waste was harmless, then waste sites would be located in areas of dense population.

But since these sites seem to only be cropping up in sparse areas, I guess there really IS suspicion of danger.

I agree with the 2nd poster, that the correct answer (C) effectively undermines the truth of the conditional in the 2nd sentence. (C) suggests that "even if nuclear waste sites were certain to pose no threat, there would STILL be good reasons for putting them in sparse rather than dense areas".

You should realize that this is a very rare but still possible occurrence on LSAT. You will sometimes Weaken an argument (or even point out the Flaw) by undermining the truth of one of the premises. It sometimes feels like cheating when it happens, because we're so mentally trained to accept the truth of the premises but debate the logic of deriving the conclusion. However, there are a few examples in which the logic is seemingly sound, but the premises are unsupported claims (not statistical facts) that could potentially be undermined.

===other answers

(A), (B), and (D) are all strengthening the argument by agreeing with the author that the reasons for favoring sparse over dense areas for nuclear waste sites include the possibly of an accident (i.e., these answers suggest that waste sites DO pose some threat to people living nearby)

(D) is technically out of scope, but the gist of it is still in line with how (A) and (B) work.

(E) also seems to strengthen the argument, if anything. It means something slightly different from the 2nd sentence of the stimulus, but it's very close in agreeing with the author's overall sentiment.

Let me know if there are any lingering questions.

[nmop_apisdn2]

The conclusion of this argument is the last sentence. "But the policy of dumping nuclear waste only in the more sparsely populated regions indicates...misgiving about safety..."

The only supporting evidence for this claim is 2 premises.

1. It is repeatedly claimed that people are not being threatened by being near a nuclear waste dump.

2. If the claim could be made with certainty (in other words, if the first premise could be made with certainty), there would not be a reason to NOT put sites there.

There is no contrapositive being reached here from the conclusion.

This conclusion simply jumps to one explanation for the occurrence of sites not being built near larger groups of people.

We can weaken this by pointing out alternate reasons for this like B does.

LOL, I think you meant C, Timmy.

[WaltGrace1983]

Just so I'm clear...

(Dumping of nuclear waste poses no threat → no reason not to locate to densely populated sites)
+
Nuclear waste is dumped only in sparsely populated sites
→
Dumping of nuclear waste does pose a threat

So the argument just gives us a conditional, shows the contrapositive, and then says that - because the sufficient condition of the contrapositive has been satisfied - the necessary condition of the contrapositive must be satisfied. In other words, because nuclear waste is dumped only in sparsely populated areas, we must conclude that it does pose a threat. The argument is weakened by simply showing that the conditional statement initially posed is not correct: there CAN be no threat while still producing a reason not to locate the nuclear waste dump in the densely populated areas."

Couldn't we also weaken this claim by showing that the placement of nuclear dumping sites was random and actually without reason? In other words, we could totally accept the argument's conditional but just say that the contrapositive's sufficient condition actually has not been satisfied? Maybe the dumping sites were put there just "because." It is weak, I know, but I it seems like there definitely is a very small gap between the necessary condition of "having no reason" and the sufficient condition being satisfied by the fact that "dumping nuclear waste happens only in the more sparsely populated regions."

[ohthatpatrick]

I agree with almost everything you said.

I wouldn't say that this author literally triggers the contrapositive, but that's the gist of his argument and that's how we could interpret it.

The contrapositive isn't actually triggered because, as you were saying:
"the fact that we dump only in sparse regions"
does not equal
"there IS some reason for not dumping in dense regions"

so it would be fair to point that out and say that "we might dump exclusively in sparse regions for no particular reason" or, equivalently, "we might avoid dumping in dense regions for no particular reason".

[BackoftheEnvelope]

This was my process for solving the question:

Conclusion: At least some threat to dumping nuclear waste
Support: It’s only dumped in more sparsely populated regions
Flaw: Takes for granted that safety is the only determinant of where nuclear waste is located OR Fails to consider other reasons why we locate nuclear waste in less densely populated areas.
Prephrase: Perhaps local political and regulatory conditions weigh more heavily in determining where nuclear waste is located. There several possible reasons why nuclear waste could be located in less densely populated areas – none of which have to do with the supposed lack of safety.
Elimination: Both (A) and (B) support the author’s notion that nuclear waste poses at least some threat to the surrounding population. (D) is an irrelevant comparison which neither strengthens nor weakens the argument since it has no bearing on the conclusion-support relationship. (E) Confirms the author’s suspicions that there’s at least some misgiving about safety.
Confirmation: (C) Provides another explanation for why nuclear waste is located in less DPA.

There's also another way of approaching the argument in the stimulus (which I found was more common among the posters here):

Conclusion: Dumping nuclear waste in more sparsely populated regions indicates at least some misgiving about safety
Support: If it posed no threat to people living nearby, there’d be no reason for not locating it in densely populated areas + We only locate sparsely populated areas

It's a bit more tricky to approach the argument in this manner for two reasons. First, it’s valid in form (denies the consequent: If A then B. Not B. Therefore not A). Second, the quantifier in the conclusion is the correct negation of the quantifier in the support:

If no threat, then would be located in densely populated areas
Not located in densely populated areas
Therefore, at least some threat

You could still weaken the argument by thinking of how to satisfy the sufficient while showing that the necessary does not have to follow:

If no threat, no reason to not locate in more densely populated areas. No threat, BUT still reason to not locate in more densely populated areas (i.e., legal, political, etc.). Sufficient occurs, necessary does not.

IMO, however, this is an example of the type of question where you really have to parse the argument to its most important parts. Again, IMO, thinking of the argument simply as "There's at least some threat to dumping nuclear waste because it’s only dumped in more sparsely populated regions" is sufficient since it allows you to easily spot the relevant flaws in the reasoning.

[JeremyK460]

dumping toxic waste (in suburbs) poses a threat to those living near it because there are reasons why we don't dump toxic waste in cities

the conclusion regarding the dangers constituted by the dumping of toxic waste in suburban areas is based on the claim that there are reasons for not dumping toxic waste in urban areas

positing your position on the basis of the existence of some probative force leaves you vulnerable to the existence of some confuting force (potential counterbalancing)

answer c for me was that confuting force - an alternative reason for the behavior apart from the asserted reason given

my analogy to the stimulus...
being able to own a firearm poses a threat to those who are near it because there are reasons why firearms are dangerous

my analogy to the answer...
there are also reasons why owning a firearm could be lifesaving

[JimW371]

The argument is wrong because "no reason not dumping in dense areas" is not equal to "must dump in dense area." Thus contrapositive does not apply here. And "no reason not dumping in dense areas" has another implied sufficient condition that requires there is actually no other reason.

(C) basically just lists other reasons than safety not to dump in dense area, then we know the original conditional statement does not work.

(E). "cannot do A until B" means "if A, then B (B is necessary to do A)." But I believe the best way to understand "until" is to forget the format and to look at the context. (E) here means "if doubt on safety, then not dense area," which is close to the illegal negation of the original, and does not weaken.

(D) states "even there is some danger or safety concern, still dense area," which strengthens the argument.