In this lesson, we're covering everyone's (least) favorite question type: Parallel Reasoning. These long-winded questions take a bit to read and can be tougher for newer students. But with a little practice, we'll have you spotting the matching argument in no time.
These questions come down to understanding each present in the passage and whether those parts lead to a
You can usually spot a Parallel question from its larger-than-average answer choices. If not, they tend to look like this:
- The pattern of reasoning in the argument is most similar to that in which one of the following?
- Which one of the following is most closely parallel in its reasoning to the argument presented?
Beware, questions occasionally present themselves the same way. That is, the question may not explicitly call out that the passage contains flawed reasoning. Read carefully.
Let's check out some examples.
Examples
PrepTest 123, Section 2, Question 12
Suppose I have promised to keep a confidence and someone asks me a question that I cannot answer truthfully without thereby breaking the promise. Obviously, I cannot both keep and break the same promise. Therefore, one cannot be obliged both to answer all questions truthfully and to keep all promises.
Start with the conclusion: we can't be obliged to answer all questions truthfully (I'll call this B) and to keep every promise (I'll call this A).
What's the support for this conclusion? The author uses a hypothetical situation to illustrate that we're occasionally in circumstances where doing B means doing not A. The author then follows up with the obvious: that we can't obviously do B and not-B simultaneously. That does it for the argument's anatomy.
But there's also this undercurrent of obligation to address. To be correct, the answer choice will need to address obligation in some way. It might be necessity, or law, or some other idea parallel to obligation, but we need it in there.
I'm predicting the parallel argument will be something like, "We said we'd do A, but there may be a circumstance whereby doing B (something we're obligated to do) we may not be able to keep our word. Therefore, we can't do both A and B in every situation." Now, this won't match an answer choice verbatim, but it gives us a working template to go find the answer.
A does just that. It reads:
It is claimed that we have the unencumbered right to say whatever we want. It is also claimed that we have the obligation to be civil to others. But civility requires that we not always say what we want. So, it cannot be true both that we have the unencumbered right to say whatever we want and that we have the duty to be civil.
The "unencumbered right" bit is a nice stand-in for A, whereas "the obligation to be civil" replaces B. Then, we get a conflict between them: "...civility requires that we not always say what we want." In other words, B occasionally requires not-A. Then, we get a matching conclusion: "So, it cannot be true both that we have [A] and that we have the duty to be [B]." Spot-on.
PrepTest 135, Section 4, Question 24
Let's try
Paleomycologists, scientists who study ancient forms of fungi, are invariably acquainted with the scholarly publications of all other paleomycologists. Professor Mansour is acquainted with the scholarly publications of Professor DeAngelis, who is a paleomycologist. Therefore, Professor Mansour must also be a paleomycologist.
This argument says if you're a paleomycologist, then you definitely know the work of your peers & colleagues. But then it says Mansour knows DeAngelis's work who is a paleomycologist, and therefore Mansour must be one too. Nonsense.
This is a classic case of confusing sufficient and necessary. It's treating the necessary condition—knowing the work of paleomycologists—as sufficient for knowing someone is a paleomycologist. That's a no-no.
Which leads us right to answer choice A. If a Global flight is delayed, all connecting Global flights are delayed. Frida's connecting Global flight was delayed, so her earlier Global flight must have been delayed. Nope—same flaw.
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That does it for the Parallel boogeyman. Hopefully you find these questions a little less intimidating. If not, keep practicing! You'll get there. See you in our next lesson where we shift from Parallel Reasoning to Parallel Principles.