Strengthen/Weaken Questions

Yup – you guessed it. These questions present you with an argument, and ask you for something that would either strengthen or weaken the argument.

Much like flaw questions and assumption questions, you should be looking for holes or “soft spots” in the argument as you read it, to try to predict what could be strengthened or weakened.

Except here, it’s usually not as gaping of a hole as it is in assumption/flaw questions. In other words, the argument is usually a pretty decent argument, with just the potential to be made better or worse, rather than an argument that is inherently flawed or missing something.

Let’s dive right in with an example from June 2007:

This is an EXCEPT question, which means that we are looking for the wrong answer. In other words, the right answer will be the one that doesn’t strengthen the argument – maybe it will weaken it or maybe it won’t have an effect either way. The four other answers will all strengthen the argument.

In summary, the argument is that the reason the Land Party won in 1935 was the fact that it addressed serious economic problems. Now, all we have to do is read the answer choices one at a time and think, “if this were true, would it make that argument stronger?” If not, then it’s the answer.

Let’s go backwards through the answer choices, because why not:

(E) says that great economic problems make a person more motivated to vote. This certainly strengthens the argument, since it shows that it was the problems that caused people to go out and vote for the Land Party!

(D) says that the Land Party was the only major party that addressed these economic issues. This also strengthens the argument, since it makes it more likely that that was the reason the party won! (If the opposite were true and all the major parties had addressed the issues, then that would destroy the argument, since how could it be the reason the Land Party won if all the losing parties did the same thing? This strategy can be useful – if the opposite of an answer choice weakens an argument, then the answer choice itself would have to strengthen it – and vice versa.)

(C) says that the Land Party was most successful during the time of the economic troubles. Of course this strengthens the argument, since it makes it more plausible that the problems were the cause of the success!

(B) says that voters tend to choose a political party that focuses on their problems. This is exactly what the argument is assuming, so of course it strengthens it!

(A) is tricky. It says that in previous elections, which we know the Land Party lost, it didn’t address economic problems – at face value, this would seem to suggest that since it only won when it started addressing economic issues, that that must have been the reason it won!

However, read it more carefully, and look for the difference between the argument and answer choice (A).

(A) says that in previous elections, the party didn’t address urban groups’ issues. The paragraph is arguing that the reason it won was because it addressed the problems of rural areas, where most of the population lives.

Thus, in past years, whether or not it addressed the issues of urban groups wouldn’t mean anything since even if it did, we might still except it to have lost, based on the reasoning of this argument. 

This was more of an exercise in careful reading. (A) is the correct answer since it does not strengthen the argument.

Now, one thing to note here is that out of the four answer choices that did strengthen the argument, they all made novel points that were not made in the paragraph. This is to be expected when looking for something to strengthen or weaken the argument. Many of my students get scared of answers that give new information that was not mentioned in the paragraph. However, that’s exactly what these questions are asking for – a new piece of information that, if true, would make the argument stronger or weaker.

Let’s look at a weaken question from the same test:

Many, many people got this question wrong! Let’s look at it carefully.

The argument is saying that, since milk heated to 50 degrees in a microwave loses half of its lysozyme, whereas milk heated to the same temperature by a conventional heat source doesn’t, it must be the microwaving method that kills the lysozyme. It can’t be the heat killing the lysozyme, since the same temperature of heat from a non-microwave source did not kill the lysozyme! This seems like a pretty solid argument.

We have to try to weaken the argument, and show that no, it somehow is the heat in the microwave that’s killing the lysozyme, even though it’s being heated to exactly the same temperature.

Let’s look through the answer choices, several of which are tricky:

(A) says that if we microwave-heated it to 100 degrees, it would kill nearly all of the lysozyme. We already know that 50 degrees kills half of the lysozyme, so this isn’t too surprising. The argument is about specifically what it is that’s killing the lysozyme – is it the microwave technology or is it simply the heat? (A) does nothing to make either one more likely than the other, so it can’t be the answer.

(B) has nothing to do with how the enzymes were killed. It just says that, after the fact, you can replace them from other sources. Irrelevant.

(C) has nothing to do with microwaves! It isn’t comparing microwaves with conventional heat sources – rather, it’s comparing conventionally heating to exactly 50 degrees with conventionally heating to hotter than 50 degrees. A liquid exposed to a hotter source will heat up faster – makes perfect sense, but so what? It doesn’t tell us anything about what’s responsible for killing lysozyme in a microwave, so it can’t be the answer.

(D) – who cares about taste? There’s no reason to suppose that this has anything to do with lysozyme killing, so bye-bye.

(E) – this is a very tricky answer, but think about it carefully. According to (E), if you heat milk to 50 degrees in a microwave, small zones within the milk will reach much higher temperatures than 50 degrees. Therefore, maybe it really is the sheer heat that is responsible for killing the lysozyme, not the microwave technology! The argument was assuming that milk in a microwave and milk heated by a conventional source are both hitting the same temperatures, so if the microwave is killing off the lysozyme and the conventional source is not, it can’t be the heat, so it must be the microwave itself. BUT, if (E) is true, zones within the microwaved milk are reaching much higher temperatures, even though it’s only being heated to 50 degrees. Therefore, maybe it really is the heat that is killing the lysozyme, and it has nothing to do with the microwave technology! Therefore, (E) weakens the argument, and is the answer.

This is a very tricky question, but if you understand precisely what the argument is arguing, you’ll see that (E) weakens it if true.

Again, the correct answer had new information (the paragraph said nothing about pockets of heat), but this didn’t make it wrong – novel information that, if true, would weaken the argument, will always be the correct answer to a weaken question.

In summary:

  • As you read the argument, look for soft spots and try to predict something that would either strengthen/weaken the argument
  • Novelty is not a reason to cross an answer choice out – rather, think “if this were true, would it strengthen/weaken the argument?”

For full clarity on very tough logical reasoning questions, check out my LSAT course.

Oh, and if you haven’t already, download your Free MasterLSAT Study Guide, which will tell you exactly what you need to do to reach a 99th-percentile score on the LSAT.

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