LSAT PrepTest 43 Section 2 Question 24 Explanation | Logical Reasoning

I didn't write the following blog post. It was already on the blog when I took over the URL. The following blog post may contain mistakes. -Steve

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This Logical Reasoning question is from the June 2004 LSAT.

This is a "parallel reasoning flaw" question, so we're looking to find an answer choice with the same logical flaw as the original argument.

As usual, let's make a concise chain of phrases (this can be done by underlining key words, once you get more experienced) to show how the argument progresses:

No seatbelt law --> not worn in motorcycles --> motorcycles more dangerous even with seatbelts

Let's make a rough pre-phrase of what this argument's flaw is. It's saying that seatbelts shouldn't be required on cars because they're not worn on motorcycles. The thing is, just because there is danger in one activity, riding a motorcycle, doesn't mean the government shouldn't try to limit danger in some other activity. So the flaw is something like "the argument presumes that if danger is allowed in one activity, it should be in another." Let's find an answer choice with the same flaw.

A) The opposite of what we want since this answer choice doesn't have the same kind of flaw as the argument does. This choice is just providing a better alternative to what the parents are already doing. It's not saying that because on bad/dangerous thing is allowed, another should be, as the argument is doing.

B) Again, the opposite of what we want because it doesn't address the flaw the argument has. This answer choice justifies allowing stress leave because sick leave is allowed. This isn't the same pattern of justifying something bad/dangerous by saying something else bad/dangerous is allowed, and that's what we're looking for.

C) Correct. Same flaw, which we've mentioned above, as the argument. The dangerous thing, standing on a ride, is justified by something else dangerous that's allowed, standing by the edge of a cliff.

D) Again, the opposite of what we want because it doesn't have the same kind of flaw. This choice is talking about what should illegal, but the argument is justifying what should be legal by what other dangerous things are legal.

E) Once again, the opposite of what we want because it doesn't have the same flaw as the original argument. It justifies doing something dangerous by the fact that it's permissible to do something which we have no reason to perceive as dangerous. Letting the dog run around in the yard isn't dangerous (or at least the answer choice gives us no reason to think it is), but the original argument uses riding a motorcycle with no seatbelt as the justification for not requiring seatbelts in cars. That isn't the same kind of flaw.

Remember:

1) Use a chain of phrases to show how the argument progresses. Pre-phrase an answer when you can. Here, we couldn't pre-phrase the actual, final answer (since there are many situations that could have the same flaw as the argument), but we pre-phrased the argument's flaw, which really helped in quickly identifying the right answer.

2) Find answer choices that are the opposite of what we're looking for and eliminate them; in this case, that means getting rid of answer choices without the flaw the argument had. I know this sounds like obvious, unhelpful advice, but it's surprising how often people can be tripped up by answers that are exactly the opposite of what they need if they aren't paying close attention.