#3 - Commentator: If a political administration is both

[Administrator]

Complete Question Explanation

Must Be True—CR. The correct answer choice is (C)

ES = Economically Successful
PIL = Protect Individual Liberties
OS = Overall Success

This stimulus establishes the following relationship:

ES
+ OS
PIL

This is a compound conditional relationship, wherein satisfying both sufficient conditions indicates
overall success. The general relationship is followed by an additional general premise that a specific
failure to care for the environment does not automatically preclude overall success.

Of course, given that the first statement is true, any failure (or, for that matter, all failures) cannot
preclude overall success if the administration is both economically successful and successful at
protecting individual liberties. Finally, we are told that this specific administration does not care for
the environment but does protect individual liberty, which are the following conditions:

PIL
+ ?
ES

By themselves, those conditions yield no viable inference, so we can expect the correct answer to
provide additional information.

Answer choice (A): This is a conclusion and cannot be supported without additional premises.
Answer choice (B): This is also a conclusion that cannot be supported without additional premises.
Furthermore, the relationship we have will never allow us to conclude that an administration is not
an overall success; inferring that a necessary condition does not occur is logically impossible.

Answer choice (C): This is the correct answer choice. This answer gives us an additional premise
in the form of a sufficient condition (Economic Success). If we add ES to PIL from the stimulus, we
can correctly infer OS. Therefore, (C) is the correct answer.

Answer choice (D): While (D) also offers an additional premise before reaching an inference, its
premise is about economic success and the inference is about caring for the environment. These two
elements were never linked in the stimulus, so this relationship cannot be inferred on the basis of the
statements above.

Answer choice (E): Like (C) and (D), (E) contains an additional premises. However, this answer
suggests that environmental protection is sufficient for overall success, while the stimulus only
suggests that environmental protection is unnecessary. Thus, this answer cannot be correct.

[ellenb]

Dear Powerscore,

First, I just want to thank you for taking the time to answer my questions.
Second, I had a question in regards to how to diagram the second and the third premise in the stimulus.

(premise 2) PIL(protects indivdual liberties) + not CE (Care Environment)-->OS

(premise 3) PIL+ not CE--->OS

Please let me know if my diagrams are correct.

Also, I seem confused with the third statement. In the explanations it was diagramed as:
PIL
+ --->OS
not ES(economical sucessfull)

Why is it diagramed as "not ES" when it should be "not CE" ?

And also, it seems like we are providing a missing link for this must be true question.
Thus we have A + B---> C

In the third premise we have A, but missing B.
So, what kind of must be true question is this? The one that provides the missing link?. Usually I thought that if we have a conditional statement and a must be true question scenario combination than the answer will be asking us to take the contra positive.

Thanks in advance!
Ellen

[Steve Stein]

Hey Ellen,

Thanks for your question. In that one, the author provides that economic success and protection of liberty means overall success:

Econ success
and overall success
protection of liberty

The author then adds that lack of care for the environment doesn't preclude overall success, as long as there is protection of liberty. The present administration has protected individual liberty, so overall success is still possible despite the administration's environmental apathy.

The author has provided pretty limited information, and a Must Be True question follows. As always, the right answer choice will be the one that passes the Fact Test--the one that can be confirmed by the information in the stimulus.

Answer choice C doesn't really provide the missing link; rather, it presents a conditional statement that can be confirmed by the author's statements:

If the present administration is economically successful (and the author already provided that the current administration protects individual liberties), then we do indeed know that the present administration is an overall success:

Econ success
and overall success
protection of liberty

None of the other answer choices can be confirmed in this way. I hope that's helpful--let me know whether it's clear--thanks!

~Steve

[netherlands]

Hi there,

I got this question correct, but I had a question about a statement that you made in the explanation. You said that "inferring that a necessary condition does not occur is logically impossible". How is that so, if we can take the contrapositive which shows conditions that have to be met in order for the originally necessary condition to be negated, and therefore not occur?

Meaning, If "Economic Success and Protecting Individual Liberties" Overall Success - Can we not then take the contrapositive to say that "No Overall Success" lack of either Economic Success or lack of Protecting Individual Liberties?

I can definitely understand how their giving us the two conditions of failing to care for the environment and failing to protect individual liberties doesn't allow us to make an inference because we need information on both Individual Liberties Protection and Economic Success to make the contrapositive.

Thanks.
netherlands

[Dave Killoran]

Hi Netherlands,

Good question. There's a difference between concluding something, and being given that piece of information (as in a premise).

If we start with A B, is it possible to prove that B occurred by adding a separate premise? No, you can't do it. It would require adding something here (aside from B, of course, because that's what we're trying to prove):

• Premise: A B
  
  Premise: ?
  
  Conclusion: B

That impossibility is what the explanation is driving at. Note that in your example, you used two premises to draw a contrapositive conclusion:

• Premise: A B
  
  Premise: B
  
  Conclusion: A

(which everyone writes out as A B for ease and speed). But, in that example, you are adding in the fact that B occurs first, and that lack of a necessary condition then allows you to conclude A.

Keep in mind that when you have an original statement like A B, a contrapositive is still is premised on the idea that if B, then A. But that if has to occur first; that is different from proving it occurred.

Please let me know if that helps. Thanks!

[netherlands]

Ok, - so when I take the contrapositive, I shouldn't consider myself to be "concluding" something, rather I am revealing an additional premise to work with.

Further, I need to remember that the lack of B in the contrapositive, when a sufficient condition, can never really be surely concluded, because the necessary conclusions can occur without it.

So the only thing that really could allow me to infer lack of B would have been additional premises with lack of B as the necessary condition.

So in this case, even if the stimulus had stated that there was a Lack of Economic Success and Lack of Protection of Individual Liberties, I couldn't be a "Must be True" that there was no Overall Success because, lack of OS would be the sufficient at that point?

Ok - so note to self, when taking the contrapositive remember I cannot make a must be true inference about the original necessary condition because it is now sufficient.

[Dave Killoran]

If I'm reading that right, you are basically correct again

The contrapositive is always true, it's just based on knowing that the necessary didn't happen. That is technically a second premise that then allows you to conclude that the sufficient did not occur. You see this in LG all the time. Example:

• Rule: L3 G4
  
  Question stem: "If G is first..." which equals G not in 4
  
  Conclusion: L is not in 3.

In the above, the rule acts like a premise, the question stem then adds another premise, and then you can draw that conclusion.

You can't prove that a necessary condition failed to occur without being told so (to make that error usually involves a Mistaken Negation), and you can't prove that a sufficient condition had to have occurred without being told so (to make that error usually involves a Mistaken Reversal).

As a reference, what you can prove when working with conditional statements is that the necessary occurred, and that the sufficient did not occur.

Thanks!

[katnyc]

I had trouble diagramming this (number 2.) I have a question, Is it a red flag and possibly a trick not to write out the conditional statements for premise two because of the words "even" and "may" since conditional statements are about guarantees?

[Robert Carroll]

katnyc,

Think about it this way - what is the conditional nature of that statement? "If A then B" or "Any time A is true, B must be true" is the nature of a conditional. Is there anything in that sentence that's as certain as a conditional? If not, don't diagram it as such. If there is some other way to diagram it (as a "some" statement, a "most" statement, something else), then do so, but here I don't think any of those apply.

Robert Carroll