LSAT PrepTest 43 Section 3 Question 16 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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Here's an Arguments question from the June 2004 test.

There's no need for a chain of phrases considering the argument's length. It's basically saying that commonplace/ordinary = no attention, so some miracles = no attention. Where's the jump in the logic here, the place where the reasoning breaks down and another assumption is required?

It makes sense that something commonplace may not get a person's attention, but the conclusion that some miracles of nature don't get our attention means we have to assume that some miracles of nature are commonplace/ordinary. That's the only way you can get this argument's conclusion (that we don't pay attention to some miracles) from it's premise (commonplace = no attention).

So our pre-phrase is something like "that some miracles of nature are commonplace/ordinary." B fits well, since it says that some commonplace things must be miracles (same thing the pre-phrase said, just reversed). Let's go through the other choices quickly:

A) Out of scope. There may be tons of things that aren't ordinary/commonplace, and it makes no difference to this argument. All that matters is whether some miracles of nature are commonplace.

B) Correct.

C) The opposite of what we want; we're looking for something that needs to be assumed and this definitely doesn't, because the argument says this to begin with! It says not only that some commonplace things don't get attention, but that all of them don't. So, we don't need this as an assumption.

D) Out of scope. This is the converse of the argument's main premise that some commonplace/ordinary things don't get attention. That converse is not necessarily true. It doesn't matter if only a few things that don't get attention are commonplace, if most are, or if all are. All that matters to this argument is if some miracles of nature are commonplace.

E) Out of scope again. This is another flip side to the argument's main premise that commonplace = no attention. It doesn't follow from the premise (maybe a lot of extraordinary things don't get our attention either) and, more importantly, it doesn't affect this argument. What matters isn't what does get our attention but what doesn't get it, since the argument's conclusion is about how some miracles don't get our attention.

Take-home points:

1) Look for the jump in the logic in assumption questions, and use a pre-phrase (not written down on the actual test or in practice, even though I do it for instruction's sake here).

2) Eliminate choices that are the opposite of what you want (in this case, something that is already in the argument and thus definitely need not be assumed) or are out of scope (if the choice doesn't address the argument directly, then surely it isn't a needed assumption for the argument to make sense).