LSAT Discussion Forum

Complete Question Explanation

Must Be True-SN. The correct answer choice is (B)

Since this is an ordinary fact-set stimulus and not an argument, the Must Be True question requires us to put the facts together in some meaningful way and come up with a valid conclusion. One simple way to do this would be to diagram the conditional relationships between the fact-set elements:

• Redistribute wealth → $ Injustice → $ Inequality → Violence

Since violence cannot be tolerated, the contrapositive chain easily leads to the conclusion that we must redistribute wealth:

• Violence → $ Inequality→ $ Injustice→ Redistribute wealth

Answer choice (B) is therefore correct.

Answer choice (A): At issue is not whether violence is justified or not, but rather what can be done to prevent violence. This answer choice misses the point and is incorrect.

Answer choice (B): This is the correct answer choice. See discussion above.

Answer choice (C): Given that the author herself adopts an abstract moral principle in the last sentence of her stimulus, it is unclear why politicians should act differently. This answer choice contradicts a central premise of this argument and is therefore incorrect.

Answer choice (D): The stimulus does not suggest that the likelihood of violence is the only situation in which we need to remedy economic injustice. This answer choice is incorrect.

Answer choice (E): While not redistributing wealth necessarily leads to conditions of economic injustice, there is no guarantee that redistributing wealth is sufficient to create justice. Since wealth redistribution is a necessary but insufficient condition for justice, this answer choice is a Mistaken Reversal of the conditional chain and is therefore incorrect.

On Lesson 3 hw (page 3-98) problem 18, I have a question in regards to the diagramming of the conditional statement with the term "unless" in it. If the term modified by "unless" becomes the necessary condition why do we begin the diagram with NOT redistribute weath? Shouldn't that be on the necessary side of the diagram?

Thanks for your question. It's really valuable to recognize that a conditional statement and its contrapositive are logically equivalent.

When we apply the Unless Formula, we get somethings along these lines:

able to reduce economic injustice --> redistribute wealth

We then have to draw the contrapositive of this statement in order to link it with the rest of the stimulus:

NOT redistribute wealth --> NOT able to reduce injustice..., etc.


It can also be valuable to recognize that every conditional statement can be worded in different ways.

For example, consider the statement "Unless you pay, you cannot get in."
Logically, this is exactly equivalent to "If you don't pay, you cannot get in."

In the same way, the first sentence of the stimulus could be worded something like this:

"If our nation doesn't redistribute wealth, we will be unable...

This would begin the diagram as follows:
NOT redistribute wealth --> NOT able to reduce injustice....

Thanks for the question! It's a good one. Let me know if this clears things up.

~Steve

Dear Powerscore,

I looked at the explanation however I am still confused on how the stimulus was diagramed.

I thought that the first sentence is diagramed as:

Able to Aleviate Economic Injustice OR Economic System will not lead to intolerable econic inequaties--->Nation Redistributes Wealth

It was diagramed as one statement in the answers.
Redistribute wealth → $ Injustice → $ Inequality

I know that unless, introduces the necessary and negates the sufficient.
So, if I have: A or B, unless C
it will be diagramed as: (bc if I negate or it becomes and) please let me know if it looks correct.
not A and not B--->C correct?

So, please let me know how to negate or/and statements when i have unless negating it. Also, how to diagram the first statment in this stimulus because I had and statment and they seem to have an or statement.

Thanks

Ellen

Hi Ellenb-

We will get this question answered for you today! Is there anyway you can re-post your original question for HW Lesson 3? It was accidentally deleted~ I apologize for the inconvenience! If you could post it in the Homework section, that would be great!

Thanks so much!

Morgan

Ellen,

You are absolutely correct in your diagram of the first sentence. "Unless" introduces a necessary condition; however, the remainder needs to be negated to become sufficient. This negation turns "and" into "or" (and vice versa). So, when simplified, the first sentence can be diagrammed as follows:

Able to alleviate injustice OR Tolerable inequality Redistribute $

Further, we have:

Intolerable inequality violence

The author argues that violence must be avoided at all costs. By the contrapositive chain, we have:

NO violence Tolerable inequality Redistribute $

This immediately proves (B) to be correct.

Hi , Even though I got the answer correctly without the diagraming it. The online explanation for the digram was unclear for me. I mean I thought the first sentence should be digram the following because Unless is an indictor for the necessary condition:

Not (Eco Injustice) → Redistribute wealth .
I think I am missing something here , or I am confused by the word unable and injustice in the 2nd sentence .

Can you explain ? Thank you

Thanks for the question. This one is a bit tricky, and I doubt I'd actually diagram it were I to come across it on test day (but that's mostly due to personal preference), but here's how I would diagram it if I chose to:

First sentence: NO Redistribute Wealth --> NO Alleviate Econ Injustice + Intolerable Econ Inequities [contra: Alleviate Econ Injustice or NO Intolerable Econ Inequities --> Redistribute Wealth]

Second Sentence: Intolerable Econ Inequities --> Violence [contra: NO Violence --> NO Intolerable Econ Inequities]. Note that this can be connected to the first sentence.

Third Sentence: Alleviate Econ Injustice/NO Violence, which of course tells you Redistribute Wealth from the contrapositive of the first sentence. And that is why B is correct.

Make sense?

Good afternoon,

I had a question regarding the use of the unless equation for #18 in MBT. The unless that is identifying the "our nation redistributes wealth" isn't typically negated is it? From what I recall the remaining terms is negated and becomes the sufficient condition.

Thank you,

Basia

Hi Basia!

You are correct, "unless" is a necessary indicator. The term modified by "unless," then, becomes our necessary condition. The remaining term is negated before it it put on the sufficient side of our diagram. The diagram in the online explanation is simply the contrapositive of that relationship.

So, using the Unless Equation, the first part of the first sentence would look like this:

NOT $ Injustice Redistribute wealth

Contrapositive:

NOT Redistribute wealth $ Injustice

Remember that a contrapositive and the "original" diagram it comes from are logical equivalents. It doesn't really matter which way you write it because it means the same thing. The Unless Equation is just a simple way for us to remember how to diagram those statements. But it is perfectly correct to diagram the contrapositive of what you would get with the Unless Equation first.

From the second part of the first sentence, we know that $ Injustice inevitably leads to $ Inequality. They then combine the first and second sentences to get the chain:

NOT Redistribute wealth $ Injustice $ Inequality violence

Does that help clear things up?

Best,
Kelsey