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Logical Reasoning: A Guide for the Perplexed

Over the years, there have been thousands of Logical Reasoning questions on the LSAT. This might seem daunting as you begin to learn the techniques to approach these types of questions, but much like shopping for the perfect summer shoe, it becomes clear that individuals can be grouped into categories. Once you begin to differentiate wedges from flats from strappy sandals, you can develop strategies for approaching whole groups rather than individuals. (Hopefully this analogy is still understandable for those of the male, non-shoe-shopping persuasion).

The same principle can be applied to the LSAT, where questions can be grouped into larger categories. Once you learn to recognize a particular question type, you can learn the best way to approach it, as well as any future questions of the same ilk.

Below is what we at Blueprint LSAT Prep call a flaw question, one of the most common question types in logical reasoning. Read and answer the following question, and when you’re done we’ll talk about it.


    School Board Director: Mr. Roberts, a high school English teacher, has put forward a proposal that would increase the number of books that students are required to read each year in English classes. He has argued that having students to read more would increase both their enjoyment and comprehension of the subject. But we should not take Mr. Roberts’ proposal seriously, as he himself failed his own high school English classes when he was an adolescent.

    The school board director’s reasoning is most vulnerable to criticism on the grounds that

    (A) it fails to specify which books high school students should be required to read.
    (B) it assumes without justification that reading books is not a worthwhile activity for students to engage in.

    (C) its discussion of Mr. Roberts’ own high school performance is irrelevant to the merits of his proposal.
    (D) it fails to mention how the director performed in his own high school English classes.
    (E) it presupposes what it sets out to establish.


In this question, we’ve got a teacher who has a plan to get students to read more. Seems like a decent idea, right? Well, the school board director doesn’t think so. And perhaps there could be good reasons to go against the plan. Perhaps forcing students to read more means they won’t read as thoroughly or as in-depth. Or maybe all this extra reading will use up time that the students could allocate to other, more important subjects. So there definitely could be good reasons to go against the proposal. But the director’s grounds are much less compelling. The director simply points out that Mr. Roberts failed his own classes when he was in high school. However, that isn’t germane to the current proposal. Many people had rocky youths and later shape up. Focusing on Mr. Roberts’s past is utterly irrelevant to whether or not it is a good idea to have students read more books, which is why (C) is the correct answer choice. Whenever you go after the source of a proposal without evaluating the merits of the proposal itself, you’re going to be faced with a flawed argument like this one.


Lets take a look at the other answer choices. (A) doesn’t work, because while it is true that the actual books weren’t specified, that’s not a problem – you wouldn’t need to know which books are being read to make an argument about how many books should be read. The director isn’t against reading in general, just against reading more, which is why (B) is wrong. (D) is true – the director doesn’t say how he himself did as an English student – but that’s fine. We shouldn’t care about his past in evaluating his argument (just as he shouldn’t care about Mr. Roberts’s past). (E) refers to a circular argument, where a conclusion is already assumed to be true without any evidence. However, that’s not happening here. The director does use different evidence to support the conclusion; the problem is that the evidence doesn’t support the conclusion.

While there are many types of flaws, practicing ones like these will get you to the point where they’re no longer confounding mysteries, but familiar friends, and you’ll be a step closer to acing the LSAT.