Weaken LSAT Questions
In the last article, we practiced finding the central assumption of an LSAT argument in order to strengthen it. Our next step is to take the process a bit further and weaken an LSAT argument. To weaken an argument, you must find the central assumption and attack it. It is as if you are finding additional evidence among the answer choices that refutes the central assumption.
This is the third and final article in a series of articles on Weakening and Strengthening questions on the LSAT Test. The series includes the following articles:
Weaken LSAT Questions
Here’s a new question to try. Take the time to answer the question using the TestSherpa method before you jump to the explanations:
- Read question stem
- Read and paraphrase the stimulus
- Prephrase your answer
- Eliminate wrong answers
During a chemistry lecture, Professor Smith combined an unidentified compound “A” with a compound “B,” creating a new compound and releasing hydrogen gas. Smith then asked his students to combine two other compounds to determine if they had similar properties to A and B. After combining the compounds, the students detected an amount of hydrogen in the surrounding air. They concluded that these two compounds were similar to A and B in the characteristic of releasing hydrogen while forming a new compound.
Which one of the following statements, if true, would most seriously weaken the students’ conclusion?
(A) Hydrogen was not the only gas found in the surrounding air.
(B) When compounds A and B were combined to form a new compound, hydrogen was released as were trace amounts of helium and oxygen.
(C) The amount of hydrogen in the surrounding air following the student’s experiment did not exceed the amount typically found.
(D) Prior to the second experiment, no hydrogen was detectable in the surrounding air.
(E) Hydrogen is flammable and such an experiment would be dangerous to allow in a classroom setting.
Using the first step of the TestSherpa four-step approach to arguments, you should have read the question first and identified it as a weakening question. If this were in a test booklet you should also circle the word “weaken.” This is important to remind you what type of question it is without having to read the entire question over. Often the LSAT will present you with an answer that strengthens the argument just to catch you if you forget the question is a weakening question. That is a wrong answer type that we categorized as a contradiction. Be on the look out for one or two of those in every weaken and strengthen question.
Second, paraphrase the argument. This argument is long-winded and contains chemistry-related information. Many pre-law students spent their undergraduate careers avoiding chemistry and science and the LSAT knows that. Don’t be intimidated. Just put the argument into your own words using simple, everyday language. You might have come up with a paraphrase like this:
The first experiment released hydrogen
+
The second experiment released hydrogen
+
(some assumption we’re supposed to figure out)
=
The second experiment was like the first
Remember to form a prephrase of what your own answer would sound like. Remember, you want to crush the central assumption. What red flags pop up to you? Does it seem strange that hydrogen in the air is the only measure? How much hydrogen? Is there hydrogen already in the air as a result of the first experiment?
Fourth, look through the answers. Scan for an answer that matches your red flag and you’ll find answer C.
(C) The amount of hydrogen in the surrounding air following the student’s experiment did not exceed the amount typically found.
If hydrogen is always present in the air and we didn’t talk about quantities, then how does hydrogen prove that the experiments are similar at all? This answer seriously weakens the argument and is the correct choice.
Next let’s consider the other answer choices.
If the answer doesn’t jump right out at you during a quick scan, read the other answers looking for familiar wrong answer choices. Remember, the test doesn’t care how you get the right answer, so eliminating the wrong answer is just as valid as picking the right answer. It just takes longer.
(A) Hydrogen was not the only gas found in the surrounding air.
Out of scope. We only care about the hydrogen, and besides, I hope there was oxygen in the air too or the students will soon die.
(B) When compounds A and B were combined to form a new compound, hydrogen was released as were trace amounts of helium and oxygen.
Also out of scope. As long as there was hydrogen that’s all we care about in this argument.
(D) Prior to the second experiment, no hydrogen was detectable in the surrounding air.
This directly affects the argument. Unfortunately is strengthens it. If there was no hydrogen before the second experiment and now there is hydrogen, you could well make the argument that the experiment released the hydrogen and is therefore similar to the first experiment. The LSAT likes to throw in wrong answers that sound like right answers. It’s the right answer to the wrong question.
(E) Hydrogen is flammable and such an experiment would be dangerous to allow in a classroom setting.
If you were tempted by this answer you’re doing too much work. Remember, only consider what is offered by the test. You might have thought that a good professor would never put his students in harm’s way, so if this were true it would indicate that the second experiment was not dangerous and thus had no hydrogen. But how do we know that this professor cares about the students? Relax and stop thinking so hard.
Summary Tips for Weakening and Strengthening on the LSAT
- You’re going to spend a lot of time in your career weakening and strengthening arguments. What you learn as a TestSherpa student will help you forever.
- Weaken and strengthen questions are very similar to assumption questions, so don’t be intimidated.
- Identify the central assumption and then support it or attack it depending on the question. Find that red flag.
- Wrong answers are often out of scope, and trap answers usually answer the wrong question. In other words, the trap answer for a weaken question actually strengthens the argument. So read carefully—the LSAT rewards attention to details.
- You know you’re going to get a lot of questions that deal with the central assumption so practice. That’s the key to confidence and a high score.
Now go back to our LSAT prep course page to read another lesson series.