#10 - Although the charter of Westside School states that

[ilenerf]

I have several questions regarding the logical reasoning section of this exam. For question 10 I chose B "the school currently has no students with learning disabilities" instead of the correct answer D "the only students with special educational needs are students with learning disabilities." This question just has me very confused, cause many of the answers were tempting, I even had trouble eliminating answer choices on this one.

[Steve Stein]

Thanks for your question. In question 10, the author’s argument breaks down as follows:

Westside high is supposed to have some students with special educational needs.
But they don’t have any students with learning disabilities, so they’re in violation.
What’s implied in this last statement is this: But they don’t have any students with learning disabilities (so they must not have any students with special educational needs), so they’re in violation.
Premise: NO special education students violation
Conclusion: NO learning disability students violation

The stimulus is followed by a Justify question, so the correct answer choice should fill in the gaps and allow for the author’s conclusion to be properly drawn. Here, the correct answer choice will link special education students with learning disability students, as follows:

Premise: No special ed. students violation
+
Needed Link: NO L.D. students NO special ed. students
Conclusion: No L.D. students NO special ed. students violation

The correct answer choice provides this conditional statement:
Special education students learning disability students
And the contrapositive provides the needed link from the diagram above:
No L.D. students NO special ed. students

Please let me know whether that clears that one up—thanks! On another note, how have you been preparing for the test thus far? Books, courses, etc?

[voodoochild]

Tutors,

I have a question about D. Here, the correct answer says "Only SED are SLD."

You have diagrammed it as "SED -> SLD"

However, the powerscore book says that "only" introduces NEC conditions. Essentially, if I say "only girls with blue eyes are beautiful",

Beautiful => Blue eyes. Correct? However, in D) SED is used as a sufficient condition. Am I missing anything?

Please help me.

[Adam Tyson]

That's a tricky one, voodoo, and the authors have placed the word "only" where they did to fool you. "Only" does indeed introduce a necessary condition, but that doesn't mean that the condition closest to "only" in the sentence is the necessary condition. You have to ask yourself which of the conditions in the sentence the "only" refers to. It might help to re-word the sentence, perhaps like this:

"Students with special education needs are only students with learning disabilities."

Another way to think of it is "there are no students with special education needs other than those with learning disabilities." This also has the same logical relationship between the two groups or conditions.

The relationship the author has set up is one that is diagrammed as SED -> LD. It's easy to be fooled by the word "only" appearing just before the condition "SED" into thinking that SED is the necessary condition. If the "only" was referring to SED, it would instead have to read something like this:

"Only those with special education needs have learning disabilities" That sentence is diagrammed LD -> SED. See the difference?

[voodoochild]

Adam,
Thanks for your response. I tried to think about the difference, but couldn't grasp it. I spent about half an hour trying to understand the difference, and gave up.

I am not sure what's the difference between these two statements:

Only girls with blue eyes are beautiful

vs.

the only students with special EDs are students with LD.

I am really lost. Can you please explain it to me? I am glad that I found this distinction, but I am not able to grasp the difference. Please help

[Steve Stein]

Thanks for your response. It's difficult to respond to a comparison between two different conditional statements, each involving two different conditions, but try this:

The only people allowed in the theater are the ones with tickets.

This could be rephrased as follows:

People are allowed in the theater only if they have a ticket.

That would be diagrammed as:

Theater Ticket

Please let me know whether that is helpful.

On another note, how have you been preparing for the test? books, courses, etc?

[Dave Killoran]

Let me try to add something quickly, as well.

You have to be very careful in trying to turn everything into a purely rule-based environment. The English language is a messy thing at times, and words can be used in many different ways, often to different effects. A word like "only," for example, can't be used as a pure indicator, mainly because the words around it have a major impact on how "only" works (or seems to work to the typical reader) and even what it is modifying (this is largely true for any word, of course).

For example, many people see the word "only" and immediately look to the physically closest condition as the necessary condition. As Adam and Steve ably pointed out, you have to be very careful with that because sometimes it works that way, other times it doesn't. It doesn't seem to work when "only" modifies a term that refers to a condition presented earlier or later in the argument. For example:

The only way home is to take the train.

Note that "only" is closest to "home," and so a lot of people diagram this sentence as:

Train Home

But, "only" actually modifies "way," and "way" refers to "train." Thus, the diagram for this sentence is:

Home Train

In Steve's excellent example, "only" modified "people," which referred to "the ones with tickets."

"Only" isn't the only word that works this way (pun intended!), other words work like this too (for example, consider how "if" typically introduces a sufficient condition, that is until "only" precedes it and it then introduces a necessary condition).

The point is that knowing the basic rules of how these terms works is helpful up to a point, but you have to remember that your interpretive abilities are being tested here.

In addition to what Steve noted, I'd also like to know when your LSAT test date is.

Thanks!

[josuecarolina]

I was doing Lesson 2 Homework for the live online course, and this REALLY helped. I was actually coming on to the forum to post about sufficient and necessary diagramming drills #18, 21, 23, and 27. By focusing so intently (mechanically?) on the indicator words I lost the forest for the trees by connecting 'geographically'. Additionally, I became completely lost due to lack of indicator words in some drills. After reading this post, I went back and just re-worded (as recommended) into logical sounding statements and got each one right.
Examples:
"Buying scalped tickets is the only way for jim to get into the concert" this is almost identical to the example in the post, right? Way is being modified, and the way to get in is buying scalped tickets. I reversed it simply because jim getting in came after "only"

next, "none but the proud are arrogant" uh-oh, no indicator words...I'm like the kid who just realized that dad let go of the back of the bike and I am riding by myself After reading the responses to the post (I added "none but" to my indicators for necessary) I kind of just pulled my head out of it and looked at what it was actually saying. By just saying If you aren't proud, you aren't arrogant got me the contrapostivie
Arrogant Proud

Anyway, thanks for the post, THANKS for the replies!

[Dave Killoran]

Hey Josue,

Thanks for the message--I'm really glad the prior posts were able to help you!

Let me take a moment to address the whole indicator words issue, but first let me say that you are headed in the right direction, and I'm really glad that when you started thinking about the meaning of the sentences that the conditions became a lot clearer

I love indicator words, because they provide an instant ability to see what the author actually said, without having to think through the "logic" of the sentence. In this sense, they are like instant knowledge and can get you to about 90% accuracy really quickly. So, early on in the lessons, we really focus on knowing those indicators. However, as you already discovered, as you go on you start to discover all sorts of variations, and that's when understanding the logic behind the sentences should become your focus (and, you're already there, so you are ahead of the game ).

The thing to remember is to not apply real world views to what you are reading. It's hard not to do that, but your job is to actually figure out what the author said. One of my favorite examples of this is #8 in that Lesson 2 drill:

8. The children go to the park when the sun is shining.

If you think about that in a "real world" context, it makes no sense (the kids have to be in the park for the sun to shine? No way!), but by using the "when" indicator it is easy to see what the author actually said. However, there won't always be an way indicator word in the sentence, and as you found, that's when you you'll really need to understand the nature of the sufficient and necessary relationship. It sounds like you are on your way there.

And you are right: that scalped ticket example is exactly like the example I used earlier in this thread. Good eye on seeing that!

Please do not hesitate to let us know if you run into any problems--we're happy to help. Thanks!

[voodoochild]

Dave,
Thanks for replying to my message. I am planning to take the LSAT early next year.

For other posters - I believe the key difference between the two sentences I posted is the word "the only" and "only." (I found this on another lawschool thread) Former makes the condition Suff, and later Necessary, something that makes logical sense.

The only way to home is to take the train. =>

Way home => The train. CorrecT?

Only way home is to take the train =>

Train => Home.

Am I correct?

Please let me know..