#2 - Bevex, an artificial sweetener used only in soft drinks

[Administrator]

Complete Question Explanation

Assumption. The correct answer choice is (C)

The LSAT writers are really trying to catch us with the question stem's language here. We might see "properly drawn" and decide that we are dealing with a Justify the Conclusion question, but the key language is actually "which one of the following MUST be true." In other words, the correct answer choice is absolutely necessary if we are to have any hope of getting to the conclusion. It is an essential part of the foundation of the argument and it cannot be removed without destroying the possibility of reaching the conclusion. Thus, we have an Assumption question, and the correct answer can be tested using the Assumption Negation Technique. The critical first task will be to identify the conclusion.

The author is saying that Bevex is safe for people because Bevex does not start giving mice cancer until the mice have been given a certain amount, which would be the human equivalent of drinking 25 cans of Bevex-sweetened soft drinks per day. How terrible is this argument? Let us count the ways.

Firstly, Bevex does not have to be administered only in soft-drink form. Perhaps one-quarter of candy bar sweetened with Bevex would cause cancer. Secondly, Bevex is not necessarily "safe" just because it does not cause cancer. If Bevex is a fast-acting brain poison, cancer is significantly less important. Thirdly, it is within the realm of possibility that someone on Earth once averaged slightly more than a can of soda each hour for a twenty-four hour period. Finally, Bevex might react differently in a human body than in a mouse body. We should always carefully consider the conditions in an experiment before we accept the results.

Hopefully, we can see that this argument is so leaky that it cannot be a Justify the Conclusion question. In fact, we may finish reading the stimulus and expect a Weaken question stem. Instead we encounter an Assumption question stem. Despite the argument's significant flaws, Bevex could be safe for people. Our task is to find an answer choice that must be true in order for the argument to continue to hobble feebly toward the conclusion. We are dealing with a Defender Assumption question because the correct answer choice will ward off an attack that otherwise threatens to put this pathetic argument out of its misery.

Answer choice (A): This is not correct because we do not need this answer choice to be true for the conclusion to be possible. Hopefully, we can toss this aside quickly. The argument is trying to say that no human will get cancer because no human will consume enough Bevex, so the rate at which cancer develops could not matter less. IF Bevex ever causes cancer, THEN it's game over for claims of Bevex's safety.

Answer choice (B): This is not the correct answer. We could imagine that the claims in answer choice B are true, but they have no impact on the subject of the stimulus. Bevex is never mentioned here, so we should not be concerned about such nonspecific claims about SOME substances being carcinogenic for mice in a lab somewhere.

Answer choice (C): This is the correct answer choice because the author needs this to be true for the conclusion to survive. We noted that a person drinking 25 cans in a day is a problem for the stimulus. With this answer choice, we remove such a possibility. Using the Assumption Negation Technique, we can see that Bevex cannot be safe if even one person goes over the 25 can limit for a given day.

Answer choice (D): This is not correct. What does weight control through soft drinks have to do with the potential carcinogenic impact of Bevex? Nothing. Not only does this answer choice fail in its attempts to subtly switch from cancer to weight management, but it also fails even to mention Bevex. We should confidently toss this one aside and never look back.

Answer choice (E): The importance of relevant studies is in play here. We know that Bevex has run studies that are relevant to cancer in humans, and certainly whatever is relevant to cancer in humans is relevant to safety in humans. Therefore, we absolutely do not need to consider the existence of other studies, especially because we might already have presumed that someone did a study on the color of Bevex or on the taste of Bevex or on the solubility of Bevex. If we even bothered to use the Assumption Negation Technique, we could quickly see that any additional studies are neutral as long as we have one study relating to safety in people.

[Leela]

Why is this an assumption question, rather than a justify question? I know "the conclusion above is properly drawn from the premises given if which one of the following is true" introduces a justify question and this question stem reads the same to me.

[Dave Killoran]

Why is this an assumption question, rather than a justify question? I know "the conclusion above is properly drawn from the premises given if which one of the following is true" introduces a justify question and this question stem reads the same to me.

Hi Leela,

Good question! The stem here reads: "In order for the conclusion that Bevex is safe for people to be properly drawn, which one of the following must be true?" While the "properly drawn" portion often is tied to a Justify question, in this case it's the "in order for" part that drives this into being an Assumption question.

"In order for" is a conditional indicator, and typically works as follows:

• "In order for X, Y must occur."
  
  This is saying that for X, we have to have another thing, which is a way of indicating necessity. So, the diagram is:
  
  X Y

Applying that to our question stem here, we get:

• "In order for this conclusion to be true, one of these answers must be true."
  
  So, the diagram is:
  
  Conclusion true one of the answers
  
  That means the correct answer is necessary for the conclusion, and that's the very definition of what an Assumption is

By the way, aside from course materials, we just did a two-part podcast on Assumption questions, which you can access here if you'd like: The PowerScore LSAT PodCast. Those discussions are in Episodes 11 and 12.

Please let me know if that helps. Thanks!

[holy115]

Hi, I have a question about the laid-out assumptions that this poor argument contains.

I agree with the points except for the following: "Firstly, Bevex does not have to be administered only in soft-drink form. Perhaps one-quarter of candy bar sweetened with Bevex would cause cancer."

In my opinion, this is not a valid assumption that the passage is making because it is stated in the passage that Bevex is only used in soft drinks. In other words, we do not have to think about the possibility that Bevex could be used in other forms such as a candy bar just like you suggested.

Any advice would be greatly appreciated!

[Luke Haqq]

Hi holy115!

You raise a valid point, but there's also support for the administrator's hypothetical in the stimulus.

The relevant language seems to be given at the outset: "Bevex, an artificial sweetener used only in soft drinks..." On the one hand, it's understandable to think from this language that the sweetener can onlybe used in soft drinks. On the other, this language doesn't necessarily require that interpretation. Rather, it's possible based on this language that it has only been used in soft drinks thus far, but not that it's impossible to use in other forms as well.

Finally, correct answers on assumption questions can sometimes require one to think about possibilities other than what is explicitly mentioned in the stimulus. For example, an alternative correct answer choice on this question might have been "Bevex does not cause imminently lethal human diseases X, Y, and Z." Something like this assumption must be true (or some other example indicating it is not safe) even though those diseases aren't mentioned, or else the conclusion that it "is in fact safe for people" based on the reasons the author states would not follow. Using the Assumption Negation technique, this would be "Bevex does cause imminently lethal human diseases X, Y, and Z"; if this were true, the argument would fall apart that it is in fact safe for people based on the reasons the author states alone.

[holy115]

The author is saying that Bevex is safe for people because Bevex does not start giving mice cancer until the mice have been given a certain amount, which would be the human equivalent of drinking 25 cans of Bevex-sweetened soft drinks per day. How terrible is this argument? Let us count the ways.

Firstly, Bevex does not have to be administered only in soft-drink form. Perhaps one-quarter of candy bar sweetened with Bevex would cause cancer.

If this is a way to attack the argument, can't we also say something like "Bevex does not have to be carcinogenic for mice." as a way to attack the argument? But this is simply rejecting the premise, which we have to take as true. I'm confused. Please help.

[holy115]

Good question! The stem here reads: "In order for the conclusion that Bevex is safe for people to be properly drawn, which one of the following must be true?" While the "properly drawn" portion often is tied to a Justify question, in this case it's the "in order for" part that drives this into being an Assumption question.

I have several follow-up questions:

1. The "properly drawn" doesn't necessarily indicate a justify question, correct?
2. Is justify question the same as a sufficient assumption question?
3. "must be true" doesn't necessarily indicate an inference question, correct?
4. How does the wording "must be true" interplay with "justify" and "assumption" questions? Do they have any relationships?
5. Let's say there's a question stem: "Based on the above stimulus, which of the following must be true?" Would this question type differ based on whether or not the stimulus contains a conclusion? If the stimulus contains a conclusion, then it would be a necessary assumption question because of the "must" indicator, while if it doesn't, then it would be an inference question, correct? And the answer should either be a valid conclusion or another premise that could be inferred through the premises aforementioned, but not both, correct?

[Luke Haqq]

Hi Holy15!

1. The "properly drawn" doesn't necessarily indicate a justify question, correct?

Correct. There could be a question stem such as, "Which of the following conclusions can be properly drawn based on the above?" In that case, you'd be dealing with a must be true question.

2. Is justify question the same as a sufficient assumption question?

Yes. For a justify question, the correct answer choice is something that is sufficient for the conclusion to be drawn.

3. "must be true" doesn't necessarily indicate an inference question, correct?

Correct, though it's very common to see that language on an inference question. The question stem at issue in this thread is an example where those words can occur in a different question type.

4. How does the wording "must be true" interplay with "justify" and "assumption" questions? Do they have any relationships?

Again, this question stem exemplifies how an assumption question can use the words must be true. Offhand, I can't think of good examples of a justify question stem that would use those words.

5. Let's say there's a question stem: "Based on the above stimulus, which of the following must be true?" Would this question type differ based on whether or not the stimulus contains a conclusion? If the stimulus contains a conclusion, then it would be a necessary assumption question because of the "must" indicator, while if it doesn't, then it would be an inference question, correct? And the answer should either be a valid conclusion or another premise that could be inferred through the premises aforementioned, but not both, correct?

The language you suggest seems to fall pretty squarely into the inference/must be true question type. Whether or not there is a conclusion, it'd still be that question type. I can see how it could potentially be confused with a necessary assumption question, but it's slightly different from the question stem here, which refers to what must be true in order for the conclusion to be properly drawn.