Q18 - It was once thought

[stephen.dewart]

Completely lost on this one as well. Clarification would be great!

[giladedelman]

Thanks for the question! This is an interesting one. We're being asked to "justify the argumentation," so we know we're looking for an assumption.

The author argues that because Envirochem and Zanar are worse for the environment than TSX-400, either those two should be banned as well or TSX-400 should be legalized.

What is the gap in the logic? In this case it's hard to spot, because the assumption is a pretty natural one to make: if a pesticide is more harmful than an illegal one, then it, too, should be illegal, or the illegal one should be legalized.

(D) is correct. It doesn't look exactly like our assumption, but let's break it down:
"One pesticide should be legal and another illegal only if the former is less harmful to the environment than is the latter." In this case the legal pesticides are more harmful, so according to this principle, they shouldn't be legal while TSX-400 is illegal. This justifies the conclusion!

(A) is out of scope. We aren't told anything about the two legal pesticides' relative levels of harmfulness.

(B) is out of scope. We don't have a situation where "neither is harmful to the environment"; at best, maybe TSX-400 is harmless, but we don't even know that.

(C) is tempting, but does environmental harm need to be the only reason to ban a pesticide? Also, this doesn't address the "or TSX-400 should be legalized" part of the conclusion.

(E) is kind of like a distorted version of (D): instead of "only if" we have "if," which reverses the conditional relationship; and instead of relative levels of harmfulness, it talks about harmless vs. harmful, which the argument never gets into.

Does that clear things up for you?

[dan]

18. (D)
Question type: Application
In this problem, the premises are primarily about the environmental problems caused by three different pesticides, and the changing understanding of those environmental problems. The conclusion is about which pesticides should be banned. The assumption here is that environmental impact is relevant to whether a pesticide is banned. Answer choice (D) addresses that assumption, and is therefore correct.

Note that the conclusion does not require an assumption about what should specifically be banned or not banned.
(A) is incorrect because the conclusion is about consistency, not whether something should be illegal.
(B) is incorrect because the conclusion is about consistency, not whether something should be legal.
(C) is incorrect because the conclusion is about consistency, not whether something should be illegal.
(E) is incorrect because the conclusion is about consistency, not whether something should be legal.

[mrudula_2005]

(C) is tempting, but does environmental harm need to be the only reason to ban a pesticide? Also, this doesn't address the "or TSX-400 should be legalized" part of the conclusion.

well couldn't we ask the same question for D? Does being harmful at all to the environment need to be the only reason to legalize or illegalize a pesticide? What im saying is, D translates to "If one pesticide should be legal and another illegal, the former is less harmful to the environment than the latter." - but in fact, as you say, we don't know that there are not a slew of factors other than environmental harm that can make a pesticide illegal. this argument only mentions one reason but does not preclude the possiblity of a bunch of other reasons. SO, when evaluating the truth of D we have to realize that both pesticides could actually be completely 100% harmless and there is no NEED that the former be less harmful to the environment than the latter...maybe they are both harmless and the second illegal one just happened to commit some other offense?

do you get what im saying? and doesn't that invalidate D (in a similar way to how your 1st point about C invalidated it?)

thanks!

[farhadshekib]

Will some from MLSAT please take a look at my explanation. I had a really tough time with this one:

P1: Once thought TSX = extremely harmful to environment;
E and Z = harmless to environment.

P2: TSX banned; E and Z not banned.

P3: Recent studies: E and Z = greater environmental harm than TSX.

Conclusion -- three options:

1) E and Z banned (along with T);
2) T legalized (while E + Z remain legalized); and
3) E and Z banned while T is legalized.

I am assuming either/or can include both in this context. If not, please correct me.

The answer choices:

A: Two pesticides (E/Z + T) should not both be legal if one (E/Z) is measurably more harmful to the environment than the other (T).

This leaves open the possibility that the more harmful pesticide (E/Z) remains legal, while the less harmful pesticide (T) remains illegal. Thus, this answer choice could actually weaken the argument.

Why? Because it does not specify which pesticide should not be legal and which one should be legal. It just says that both cannot be legal at the same time.

Moreover, the conclusion provides other options; for example, we can legalize all three or ban all three. This answer choice does not address the other options, so it cannot possibly justify the conclusion (i.e. validate it 100%).

B: contradicts the stimulus; the conclusion leaves open the possibility that all three pesticides can be simultaneously legalized (regardless of how harmful they are to the environment).

C: It doesn't address why one should be legal and another illegal, which is the crux of the argument. Over all, this is out of scope.

D: One pesticide should be legal (E or Z) and another illegal (T) only if the former (E or Z) is less harmful to the environment than is the latter (T).

In other words, we can diagram it like this:

E or Z legal + T illegal (as is the current case) --> then E or Z must be less environmentally harmful than T.

The stimulus, however, leads us towards the contrapositive: that is, it suggests that "E + Z each cause greater environmental harm than does [T]".

We can diagram it like this:

~ E or Z = less environmentally harmful than T --> ~ E or Z legal + T illegal.

In other words: If E or Z is not less harmful to the environment than T (we know it’s not), then E or Z cannot remain legal while T remains illegal.

Thus, either E, Z + T should become illegal, or E, Z and T should become legal, or E and Z could become illegal while T becomes legal.

Thoughts?

[timmydoeslsat]

I chose D by process of elimination. However, I am not sure how one can say that this justifies the conclusion of "EZ being illegal or T being legal."

First, could it not be the case that the author would be OK with EZ being illegal AND T being legal? Is the author implying that only one of the two choices must be selected?

Second, the logic of choice D is:

A should be legal and B should be illegal ---> A is less harmful than B

Contrapositive is:

A is more harmful or the same harm as B ---> ~[A should be legal and B should be illegal]

In other words, at least one of those two items must be negated, perhaps both.

I am having a difficult time how this justifies both claims in the conclusion.

The necessary condition of this contrapositive HAS VAST MEANINGS. You are essentially saying NOT BOTH A being legal and B being illegal. This has a multitude of ways of being expressed, correct?

Analogous situation:

[A and B]

~ [A and B]

1)~A and B
2)~A and ~B
3)A and ~B

[ManhattanPrepLSAT1]

This is great work farhadshekib and timmydoeslsat!

Let me start by confirming farhadshekib's solution, it's tremendous and accurate. It's more like a proof!

I am having a difficult time how this justifies both claims in the conclusion.

The necessary condition of this contrapositive HAS VAST MEANINGS. You are essentially saying NOT BOTH A being legal and B being illegal. This has a multitude of ways of being expressed, correct?

Analogous situation:

[A and B]

~ [A and B]

1)~A and B
2)~A and ~B
3)A and ~B

Timmy, your understanding of the contrapositive is right on. Think of the possibilities here and the vagueness of the conclusion.

Current situation
EZ (legal) TSX (illegal)

Every other possibility
EZ (legal) TSX (legal)
EZ (illegal TSX (legal)
EZ (illegal) TSX (illegal)

Notice that each of the other possibilities would satisfy the conclusion that either TSX should be made legal or EZ should be made illegal, or both!

Answer choice (D) does utilize the contrapositive. The sufficient condition (of the contrapositive) would be met since the EZ is not less harmful than TSX, and the conclusion would be satisfied, since the conclusion doesn't really specify what should happen, but rather simply claims that the current state of affairs should no longer exist.

Hope that helps, but great work you two!

[goriano]

I am having a difficult time how this justifies both claims in the conclusion.

The necessary condition of this contrapositive HAS VAST MEANINGS. You are essentially saying NOT BOTH A being legal and B being illegal. This has a multitude of ways of being expressed, correct?

Analogous situation:

[A and B]

~ [A and B]

1)~A and B
2)~A and ~B
3)A and ~B

I don't understand timmydoeslsat's issue with the contrapositive of (D) and want to know if I am missing something.

(D) says "One pesticide should be legal and another illegal --> former is less harmful to the environment than the latter"

Essentially, the format is A and B --> C

So wouldn't the contrapositive just be ~C --> ~A OR ~B?
That is, "if the former is MORE harmful to the environment than the latter --> one pesticide should be illegal OR another legal."

Doesn't that match up exactly with the conclusion?

[ManhattanPrepLSAT1]

Happy to explain...

Timmy, you're correct, but there's an easy way of expressing all of those options simultaneously. Notice what they all have in common.

~ [A and B]

1)~A and B
2)~A and ~B
3)A and ~B

Either that A is not selected or that B is not selected. So the contrapositive of

A and B ---> C , would be

~C ---> ~A or ~B

Essentially, the format is A and B --> C

So wouldn't the contrapositive just be ~C --> ~A OR ~B?

Exactly right goriano!

[cdjmarmon]

Im very thrown off by the answer choices, especially D, becuase they one mention one pesticide vs. another but the argument establishs E and Z as 2 separate pesticides.

So to me an answer like D doesnt really make sense becuase of the options we have and the fact it only brings up one pesticide being illgal and another being legal.

What about the 3rd pesticide E or Z? Say T becomes legal and E becomes illegal what happens to Z? Its not covered by the rule in D.

[ManhattanPrepLSAT1]

What about the 3rd pesticide E or Z?

I get the confusion here, which I think is coming from two sources. First the language of answer choice (D) doesn't make it clear that there are actually 3 pesticides in the argument. The reason, answer choice (D) still works is that whatever applies to Envirochem would also apply to Zanar, and vice-versa. So to compare Enivorchem and TSX-800 based on the principle would suggest that the out come of the principle would als apply to Zanar.

The other issue is the use of abstract language. Answer choice (D) refers to a pesticide being legal vs illegal, but doesn't refer directly to any specific pesticide. That's actually a good thing, because the argument's conclusion is flexible and doesn't proscribe a specific course of action, but allows the decision to go either way. Either TSX-800 should be made legal, or those other two should be made illegal.

Hope that helps!

[kylelitfin]

What about the 3rd pesticide E or Z?

I get the confusion here, which I think is coming from two sources. First the language of answer choice (D) doesn't make it clear that there are actually 3 pesticides in the argument. The reason, answer choice (D) still works is that whatever applies to Envirochem would also apply to Zanar, and vice-versa. So to compare Enivorchem and TSX-800 based on the principle would suggest that the out come of the principle would als apply to Zanar.

The other issue is the use of abstract language. Answer choice (D) refers to a pesticide being legal vs illegal, but doesn't refer directly to any specific pesticide. That's actually a good thing, because the argument's conclusion is flexible and doesn't proscribe a specific course of action, but allows the decision to go either way. Either TSX-800 should be made legal, or those other two should be made illegal.

Hope that helps!

This was SUPER helpful. This question destroyed me as I had an issue juggling the three different pesticides in relation to answer choices.

While the above discussion about contrapositives was helpful, with a minute or so to answer the question I was becoming stressed about how to tackle this issue simply.

When you pointed out that E/Z were essentially the same (they are legal and illegal together) I plugged it in to the answer choices.

D. TSX should be legal and E/Z illegal if TSX is less harmless to the environment than E/Z.

Bingo. Simple.

Noticing these variables are essentially the same really simplifies this stimulus. Thank you!!

[alana.canfield]

(E) is kind of like a distorted version of (D): instead of "only if" we have "if," which reverses the conditional relationship; and instead of relative levels of harmfulness, it talks about harmless vs. harmful, which the argument never gets into.

If (E) had said the exact same thing as (D) with the only difference being "if" instead of "only if", would (E) be the better answer? I believe that both the necessary (D) and sufficient (E) forms would justify this question, but the sufficient form seems to be more in line with the argument.

[timmydoeslsat]

The problem with many of these answer choices is that they are not considering that we have pesticides in which we know harm as is relative to one another. We have evidence to suggest that all three of these pesticides are harmful to some extent to the environment. Now it may be true, according to the studies, that some are more so than the other. However, this does not mean that the pesticide that is less harmful than another is, infact, harmless to the environment.

So I would say that if E were reworded with only if, you would be correct. It would give us the ability to negate the necessary side and end up with the same result as D.

[alana.canfield]

The problem with many of these answer choices is that they are not considering that we have pesticides in which we know harm as is relative to one another. We have evidence to suggest that all three of these pesticides are harmful to some extent to the environment. Now it may be true, according to the studies, that some are more so than the other. However, this does not mean that the pesticide that is less harmful than another is, infact, harmless to the environment.

So I would say that if E were reworded with only if, you would be correct. It would give us the ability to negate the necessary side and end up with the same result as D.

That's an interesting take - thank you. I think I phrased my question poorly though - I was asking about the case where these are the two choices:

(D) One pesticide should be legal and another illegal ONLY IF the former is LESS HARMFUL to the environment than the latter.
(E) One pesticide should be legal and another illegal IF the former is LESS HARMFUL to the environment than the latter.

So in this case (D) and (E) are exactly the same (the comparative nature of harmfulness is retained in E) and the only difference between the two choices is just one single word - "only". So the choice is between something being more/less harmful as a sufficient condition or as a necessary condition. I feel the sufficient condition would be "stronger" of a principle and match the passage better, but I'm not sure. I was a little surprised they said "only if" in (D) and I was anticipating that being a sufficient condition, not a necessary one.

[timmydoeslsat]

Neither of those constructed answer choices would be correct.

The difference between "only if" and "if" is huge, of course, and I have no doubt that you know that.

We have an argument that is concluding that the treatment of these 3 pesticides should be the same amongst each other. The arguer wants the legal status to be the same for these three. We need a principle to validate this in the argument.

Answer choice D is using the denial of the necessary condition to arrive at, if you will allow me to paraphrase, "dont give different legal statuses between two pesticides."

How we arrived at the idea is due to us knowing full that the necessary condition can be denied. We know that the legal one is more harmful.

I am going to take your two answer choices and say why they will not work.

(D) One pesticide should be legal and another illegal ONLY IF the former is LESS HARMFUL to the environment than the latter.

We cannot deny the necessary side. The former is more harmful. We cannot use this.

(E) One pesticide should be legal and another illegal IF the former is LESS HARMFUL to the environment than the latter.

Not only do we not have the sufficient condition to trigger this, as the former is more harmful than the latter, but its construction will never help validate our argument.

This answer choice is doing this:

XXXXX ---> One pesticide should be legal and another illegal

We cannot use this construction to arrive at: ~One pesticide should be legal and another illegal.

This will not work.

[alana.canfield]

Quote:
(D) One pesticide should be legal and another illegal ONLY IF the former is LESS HARMFUL to the environment than the latter.


We cannot deny the necessary side. The former is more harmful. We cannot use this.

Hmm. I think you misread this - the answer I wrote that you quoted above actually is the real correct answer choice, word for word. I think I mislead you by capping the "less harmful" part as if it were different; I just capped it because I thought it was important. Sorry for the confusion.

This answer choice is doing this:

XXXXX ---> One pesticide should be legal and another illegal

We cannot use this construction to arrive at: ~One pesticide should be legal and another illegal.

This will not work.

Now I see my misunderstanding. Thank you!

[aznriceboi17]

I was unsure about one thing: I follow farhadshekib's argument that

(D) allows for T = legal, E/Z = illegal

But I wanted to double check, the scenario above is in fact covered by the conclusion, which says either E/Z become illegal or T becomes legal. To get to T=legal and E/Z=illegal, we need BOTH measures in proposed in the stimulus to occur.

[christine.defenbaugh]

I was unsure about one thing: I follow farhadshekib's argument that

(D) allows for T = legal, E/Z = illegal

But I wanted to double check, the scenario above is in fact covered by the conclusion, which says either E/Z become illegal or T becomes legal. To get to T=legal and E/Z=illegal, we need BOTH measures in proposed in the stimulus to occur.

Absolutely! But remember, "or" on the LSAT always allows for the possibility of both unless it is explicitly stated otherwise. So, the conclusion might as well read something like this:

If E/Z does more env damage than TSX, then either E/Z should be banned, or TSX should be allowed, OR BOTH

And this makes sense - if one turns out to the be worse, then having the worse one illegal and the better one legal seems potentially reasonable. Ban 'em both, legalize 'em both, or have the worse one banned and the better one legal, but whatever you do, don't let the worse one be legal while the better one is banned!

Does that help a bit?