#12- Vague laws set vague limits on people’s freedom

[Administrator]

Complete Question Explanation

Justify the Conclusion—SN. The correct answer choice is (A)

The argument can be analyzed as follows:

Premise: Vague laws set vague limits on people’s freedom.

Premise: Vague limits on people’s freedom makes it impossible for them to know for
certain whether their actions are legal.

Conclusion: Under vague laws people cannot feel secure.

There is a new element in the conclusion—“cannot feel secure”—that must be justified. There is also
an unconnected element in the premise—“know for certain whether their actions are legal”—that
will likely appear in the answer choice. Unfortunately, four of the answer choices contain those two
elements. Only answer choice (D) does not contain both, and as (D) also contains the “vague law”
element that appears in both a premise and the conclusion, we can eliminate (D) for the moment.

Given the plethora of answers that remain in contention, first examine the conditional structure that
is extant in the stimulus:

Premises: Vague laws Vague limits Know actions are legal

Conclusion: Vague laws Secure

Abstractly, this relationship is similar to:

Premises: A B C

Conclusion: A D

The relationship that must be added to the premise to prove the conclusion is:

C D

Translating the diagram back to the terms used in our premise and conclusion, we need a statement
similar to the following:

Know actions are legal Secure

Of course, the contrapositive of this statement would also be acceptable. Answer choice (A) is the
contrapositive and thus (A) is correct.

Answer choice (B): This answer is incorrect because it has a different level of certainty than the
conclusion: this answer uses the phrase “might not” when the conclusion uses “cannot.” If this flaw
were corrected, the answer would be correct.

Answer choice (C): This answer is the Mistaken Negation of the correct answer.

Answer choice (D): This answer was eliminated previously. This answer is also a Mistaken Negation
of the conclusion.

Answer choice (E): This answer is also the Mistaken Negation of the correct answer.
If you found yourself in trouble on this question, understanding that answers such as (C) and (E) are
identical would allow you to eliminate them under the Uniqueness Rule of Answer Choices (which
states that the correct answer must have unique properties and that any two answers that are identical
must both be incorrect).

[SherryZ]

Dec 2001 LSAT, Sec 3, Q12:

My analysis is:
Premises:
Vague Law NOT known for certain
Vague Law NOT secure

So I found the assumption should be:
NOT known for certain NOT secure

I found that A and B both satisfy the assumption that I found above. Could you tell me why B is wrong?? If I make any error in analysis, please point it out.

Thank you so much for your help!

----Sherry

[BethRibet]

Hi Sherry,

Thanks for your question. You're on the right track, but the flaw in answer choice B is that the phrasing "might not" does not correspond to the phrasing "cannot" in the conclusion. The former still leaves possibility, the latter does not. Let us know if that doesn't help clear it up!

Beth

[Dazhiw]

Hi there,

Would you please explain to me how to get the following relationship

"Vague laws ----------> Vague limits ---------->/know actions are legal

Vague laws ---------> /Secure"

without any conditional indicator?

Thanks.

[Steve Stein]

Hi,

That's a good question; the test makers often look to avoid using indicators to make questions more challenging. In this case, the presence of a recurring element ("vague laws"), followed by a justify question, in addition to the conditional indicators present in the answer choices, might tell you to be on the lookout for conditional reasoning. As you noted, vague laws set vague limits which makes it impossible for people to know whether their actions are legal:

vague laws vague limits know whether actions are legal

The author concludes that people cannot feel secure under vague laws:

vague laws able to feel secure

The stimulus is followed by a justify question, so we can apply the Justify Formula: the premises from the stimulus, in addition to the correct answer choice, will justify the author's conclusion.

Correct answer choice (A) provides that people can feel secure only when the'y can know for sure whether their acts are legal:

able to feel secure know whether actions are legal

Since the negated version of the knowledge element appeared in the stimulus, that tells us we might consider the contrapositive of this choice (which would also include the negated version):

know whether actions are legal able to fell secure

When we add this choice to the chain discussed above, the author's conclusion is justified:

vague laws vague limits know whether actions are legal able to fell secure


I hope that's helpful--please let me know whether this is clear--thanks!

Steve

[Dazhiw]

Hi,

That's a good question; the test makers often look to avoid using indicators to make questions more challenging. In this case, the presence of a recurring element ("vague laws"), followed by a justify question, in addition to the conditional indicators present in the answer choices, might tell you to be on the lookout for conditional reasoning. As you noted, vague laws set vague limits which makes it impossible for people to know whether their actions are legal:

vague laws vague limits know whether actions are legal

The author concludes that people cannot feel secure under vague laws:

vague laws able to feel secure

The stimulus is followed by a justify question, so we can apply the Justify Formula: the premises from the stimulus, in addition to the correct answer choice, will justify the author's conclusion.

Correct answer choice (A) provides that people can feel secure only when the'y can know for sure whether their acts are legal:

able to feel secure know whether actions are legal

Since the negated version of the knowledge element appeared in the stimulus, that tells us we might consider the contrapositive of this choice (which would also include the negated version):

know whether actions are legal able to fell secure

When we add this choice to the chain discussed above, the author's conclusion is justified:

vague laws vague limits know whether actions are legal able to fell secure


I hope that's helpful--please let me know whether this is clear--thanks!

Steve

Hi Steve

Thank you very much for the very detailed explaination.

I'm sorry that I did not make my question clear at the begining. I totally understand your reasoning to the question. However, the most frustrating problem for me is that I can not see the conditional relationship from the stimulus.

Can you explain to me how do you get the conditional diagrams from the stimulus without any indicator? (i have read your explaination of another question http://forum.powerscore.com/lsat/viewto ... =13&t=1796 , and it make a lot sense to me too, but when it comes to this sentence, i still can not get it.) I know it will be a big stumbling block for me if i can not figure it out.

Thank you again.
Dazhi

[Steve Stein]

Hi Dazhi,

Thanks for your response. To review, for other students who might be reading this post, it is important to note that the condition "vague laws" is repeated within the stimulus. Given that, and the fact that the stimulus is followed by a justify question, and the presence of indicator words in the answer choices, we might be looking for conditional reasoning. If there are no indicator words present, you can change the phrasing so that it relays the same idea but does include indicator words, For example:

Vague laws set vague limits: if something is a vague law, then it sets vague limits

Vague limits make it impossible for people to know whether their actions are legal:

If there are vague limits, then people are unable to tell whether their actions are legal.

I hope that's helpful! Please let me know whether this is clear--thanks!

~Steve

[Nikki Siclunov]

The argument is structured as follows:

• Premise: Vague laws NOT certain
  
  Conclusion: Vague laws NOT secure

To justify the conclusion, we need to establish the following link:

• Justify: NOT certain NOT secure.

In other words, if someone isn't certain that their actions are legal, then they wouldn't feel secure. The contrapositive of that idea also works: if some does feel secure, then they must know for certain whether their actions are legal (Secure Certain).

Answer choice (A): Secure Certain This is the contrapositive of our prephrase, and is therefore correct.
Answer choice (B): The word "might" is sufficient to throw this out of consideration.
Answer choice (C): Certain Secure. Mistaken Reversal of the correct answer.
Answer choice (D): Laws NOT vague Secure. This leads nowhere.
Answer choice (E): Certain Secure. This is a Mistaken Reversal of answer choice (A). Since answer choice (A) is the contrapositive of our prephrase, we can also think of answer choice (E) as the Mistaken Negation of our prephrase.

Note that the Mistaken Negation and the Mistaken Reversal are contrapositives of each other! It's really the same error in reasoning said in two different ways. The MR confuses a necessary condition for a sufficient one. The MN confuses a sufficient condition for a necessary one. Whether you conceptualize the error in answer choice (E) as the MN or the MR of the missing link does not matter: both are correct, depending on whether you prephrased the positive or the contrapositive form of that link.

[adkirk88]

I have a question for further explanation on why "D" is wrong.

I narrowed this question down to A and D but thought D was more attractive because it linked the beginning of the chain to the new element in the conclusion. While typing this I realized D is simply a contrapositive of the stated conclusion that needs justifying. Is this why it's not able to justify the conclusion? Because it only addresses what has yet to be linked to the whole argument?

The workbook covers this question and states that D is a mistaken negation which was confusing to me. Is that possibly an error? If not could you explain why D is a mistaken negation?

Thank you very much!

[Adam Tyson]

Happy to help, adkirk88, and I'll pretty much be pointing you back to Nikki's explanation in this thread. The conclusion is "under vague laws people cannot feel secure." As a conditional statement, that's:

Vague Laws Secure

Answer D is "People can feel secure if they are governed by laws that are not vague." That "if" is a sufficient condition indicator, so this answer is diagrammed as:

Vague Laws Secure

It is, as we described, a Mistaken Negation, because it took the original terms and simply negated them while leaving them in their original order. A Mistaken Negation cannot justify a conditional claim - you need a contrapositive to do that, or to connect a missing link in a conditional chain.

Answer A provides the missing link between a premise about certainty to a conclusion about security. If security requires certainty, and we do not have certainty, then we cannot have security.

Did you perhaps misdiagram answer D as Secure Vague Laws? That would be the contrapositive of the conclusion, but it would not be a correct interpretation of that answer choice. Take another look and let us know if you still need a hand with it.